Article

Empirical Response Spectral Attenuation Relations for Shallow Crustal Earthquakes

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Abstract

Using a database of 655 recordings from 58 earthquakes, empirical response spectral attenuation relations are derived for the average horizontal and vertical component for shallow earthquakes in active tectonic regions. A new feature in this model is the inclusion of a factor to distinguish between ground motions on the hanging wall and footwall of dipping faults. The site response is explicitly allowed to be non-linear with a dependence on the rock peak acceleration level.

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... The first attenuation relationship used in this study is the García et al. (2005) relation which was used to model the ground motion in seismic sources located inside Kuwait. The second is the Abrahamson and Silva (1997) which was applied to model the ground motion in the sources surrounding Kuwait for the three seismotectonic source models. This model estimates the ground motion of shallow crustal earthquakes and takes into account some geotectonic consideration such as the type of faulting and the type of soil which had been identified for each seismic source. ...
... Figure 17 shows the effect of the variations of the GMPE for the seismic sources of the first seismotectonic model on the seismic hazard. The hazards calculated using the Abrahamson and Silva (1997) and García et al. (2005) relations show higher values than those calculated by using the attenuation relations of Youngs et al. (1997) and García et al. (2005). The acceleration values are close for both attenuation relations at the PGA and the 0.1-s spectral period and increases noticeably from the spectral periods 0.2 to 4 s. ...
... The acceleration values are close for both attenuation relations at the PGA and the 0.1-s spectral period and increases noticeably from the spectral periods 0.2 to 4 s. This is due to the contribution to the hazard from the shallow crustal earthquakes described by Abrahamson and Silva (1997) relation at these cities is largest. Fig. 16 The sensitivity to the maximum magnitude for the 475-year return period UHS on bedrock ...
Article
The outcomes of this study are necessary to assess seismic hazard in Kuwait. The noticeable increase in urban development and construction of tall structures and skyscrapers highlights the importance of seismic risk analysis and the creation of a unified seismic code for Kuwait. This paper can be considered as an initial step through the assessment and deaggregation of seismic hazards in Kuwait. To achieve this purpose, a complete seismic catalog for Kuwait and the active Zagros Seismic Belt has been created containing all the available historical and instrumental earthquakes, unified in magnitude and foreshocks and aftershocks removed. Alternative seismotectonic models were built basing on structural geological situation, seismicity and focal mechanisms. The recurrence parameters along with the maximum expected earthquake from all seismic sources were basically estimated. Appropriate ground motion prediction relation within a logic tree formulation was fundamentally used in creating seismic hazard maps. A state-of-the-art probabilistic approach is used in this study to produce hazard maps at 75, 475, 975, and 2475 years return periods (equivalent to 50%, 10%, 5%, and 2%, respectively, probability of exceedance in 50 years) at the PGA, 0.1, 1 and 4 s spectral periods. The hazard maps were computed using a spacing grid of 0.1° × 0.1° across the Kuwait area. Uniform hazard spectra and deaggregation of seismic hazard have been established for the governorates of Kuwait. Additionally, a sensitivity analysis was performed for theses governorates to reduce uncertainties in the seismotectonic source models, predictive ground motion equation and maximum expected earthquake magnitude. These results with vulnerability index are essential components for seismic risk analysis in Kuwait.
... With the increasing number of strong motion recordings of large earthquakes, more aspects including the type of faulting effect, hanging wall effect, and nonlinear site effect have been introduced in GMPEs ( Abrahamson and Silva 1997;Campbell and Bozorgnia 2003;Ambraseys et al. 2005;Cauzzi and Faccioli 2008;Bindi et al. 2007;Jiang et al. 2017). Compbell and Bozorgnia (2003) established a GMPE for vertical SA that accounted for the effect of the type of faulting and hanging wall effect. ...
... Compbell and Bozorgnia (2003) established a GMPE for vertical SA that accounted for the effect of the type of faulting and hanging wall effect. Abrahamson and Silva (1997) and Compbell and Bozorgnia (2003) introduced a term for the hanging wall effect term, but there were a limited number of strong motion recordings showing obvious characteristics of the hanging wall effect. As a result, these works can be considered initial attempts to examine hanging wall effect. ...
... For the selected recordings, we calculated the Fourier amplitude spectrum and displacement time history. Next, the effects of the high-pass cutoff frequency on the Fourier spectrum and displacement time history were investigated visually, according to Abrahamson and Silva (1997). The results suggested that the highpass cutoff frequency of 0.05 Hz was accompanied by a slight impact of low-frequency noise on the displacement time history. ...
Article
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A ground motion prediction equation (GMPE) that can predict the vertical 5%-damped spectral acceleration (SA) in western China was formulated. To this end, a dataset that included the strong motion recordings of this region was constructed. Explanatory variables for the GMPE were identified, and a full set of final model coefficients was obtained using the random-effects method. We compared the results of this study with those of previously published work and the data of the 2019 Changning Ms 6.0 earthquake. The results indicate that the vertical SA depends on not only magnitude and distance but also the type of the faulting and linear site response. The nonlinear site response and depth to the top of rupture (Ztor) have slight effect on the vertical SA. The residual distribution, which exhibited no obvious relationship with the explanatory variables or the agreement between the predicted and observed vertical SA of the 2019 Changning Ms 6.0 earthquake, suggested good ability for vertical SA prediction in western China. Finally, the vertical-to-horizontal (V/H) ratio is affected by the magnitude, distance, and type of faulting, and near-source V/H ratio curves with respect to period at soil sites and rock sites for large earthquakes exhibit single-peak and double-peak characteristics, respectively.
... The strong ground motion acceleration records for the Eastern Anatolia are very limited. The Abrahamson-Silva (1997) [94] and Campbell (2003) NGA G Motion Relations [95], which is valid for shallow earthquakes around the world, t izer-Kalkan (2009) [96], which is valid in active tectonic zones around the world an (2008) [97] attenuation relations, which is developed for strike-slip shallow earth were used in the study. The software program obtained peak ground acceleration as a function of the return periods. ...
... The strong ground motion acceleration records for the Eastern Anatolia region are very limited. The Abrahamson-Silva (1997) [94] and Campbell (2003) NGA Ground-Motion Relations [95], which is valid for shallow earthquakes around the world, the Graizer-Kalkan (2009) [96], which is valid in active tectonic zones around the world and Idriss (2008) [97] attenuation relations, which is developed for strike-slip shallow earthquakes, were used in the study. The software program obtained peak ground acceleration values as a function of the return periods. ...
... The strong ground motion acceleration records for the Eastern Anatolia region are very limited. The Abrahamson-Silva (1997) [94] and Campbell (2003) NGA Ground-Motion Relations [95], which is valid for shallow earthquakes around the world, the Graizer-Kalkan (2009) [96], which is valid in active tectonic zones around the world and Idriss (2008) [97] attenuation relations, which is developed for strike-slip shallow earthquakes, were used in the study. The software program obtained peak ground acceleration values as a function of the return periods. ...
Article
Full-text available
Determining the earthquake hazard of any settlement is one of the primary studies for reducing earthquake damage. Therefore, earthquake hazard maps used for this purpose must be renewed over time. Turkey Earthquake Hazard Map has been used instead of Turkey Earthquake Zones Map since 2019. A probabilistic seismic hazard was performed by using these last two maps and different attenuation relationships for Bitlis Province (Eastern Turkey) were located in the Lake Van Basin, which has a high seismic risk. The earthquake parameters were determined by considering all districts and neighborhoods in the province. Probabilistic seismic hazard analyses were carried out for these settlements using seismic sources and four different attenuation relationships. The obtained values are compared with the design spectrum stated in the last two earthquake maps. Significant differences exist between the design spectrum obtained according to the different exceedance probabilities. In this study, adaptive pushover analyses of sample-reinforced concrete buildings were performed using the design ground motion level. Structural analyses were carried out using three different design spectra, as given in the last two seismic design codes and the mean spectrum obtained from attenuation relationships. Different design spectra significantly change the target displacements predicted for the performance levels of the buildings.
... Kowsari et al. [4,5] recalibrated the ground motion models (GMMs) to the dataset using Bayesian regression and Markov Chain Monte Carlo simulations which allow limited strong motion data to be combined with the prior information, and can well overcome sparse data in the research region. With the improvement of regression methods [6,7] and the accumulation of strong motion recordings, GMPEs gradually considered the influence of style-of-faulting, hanging-wall effect, or linear and nonlinear site response [8][9][10][11]. In 2008 and 2014, PEER NGA-West1 and NGA-West2 established a database containing strong motion data and related metadata in shallow crustal active tectonic regions worldwide. On this basis, five teams considered the earthquake source characteristic (magnitude, style-of-faulting, hanging-wall effect), path effect (distance), site effect (linear/nonlinear response of soil, basin response), and regional differentiation. ...
... We consider the influencing factors such as magnitude and distance saturation effects, geometric attenuation, style-of-faulting, hanging-wall effect, linear/nonlinear site response, and anelastic attenuation in our GMPE. According to the above research purpose and the type of data required by our GMPE, this paper selects earthquakes and strong motion recordings according to the following ten criteria: (1) shallow crust earthquakes within 30 km of hypocentral depth; (2) finite fault model or focal mechanism solution of earthquakes are known; (3) remove recordings of aftershocks which occurred within or near the surface projection of the mainshock rupture plane and within the Gardner-Knopoff [33] time window [32]; (4) remove the recordings of the earthquakes that occurred in the stable tectonic regions (e.g., Sichuan Basin); (5) remove earthquakes with too few recordings (related to magnitude), such as (a) M W < 5.0 and N < 5, (b) 5.0 ≤ M W < 6.0 and N < 3, (c) 6.0 ≤ M W < 7.0 and N < 2, where N is the number of recordings; (6) remove recordings of low quality, such as missing pre-event memory, having abnormal interference, and appearing multiple jumps; (7) remove recordings on non-free-field sites; (8) two horizontal component recordings of each station should not be missing; (9) each station needs to have observed or estimated site V S30 described below; and (10) recordings within 300 km of R rup . ...
... W − 6); 6 < M W < 6.5 1; M W ≥ 6.5(8) f hng,Z = { 0; Z TOR ≥ 20 (20 − Z TOR )/20; 0 ≤ Z TOR < 20 (9) f hng,δ = { 1; δ ≤ 70 (90 − δ)/20; δ > 70(10) Distribution of intra-event residuals (ε) with respect to (a) M W , (b) R rup , (c) V S30 , (d) A 1100 for PGA. Black circles and error bars represent the mean and 95 thpercentile confidence limits of mean binned residuals, respectively. ...
Article
In this paper, we collect and process free-field strong motion recordings from 70 earthquakes for 4.2 ≤ MW ≤ 7.9 at 0 < Rrup < 300 km between 2008 and 2018 in the active tectonic regions of southwest China, and then establish a dataset containing 1324 average horizontal ground motion (ROTD50) and corresponding metadata such as parameters of the earthquake source, distance, and site. A new ground motion prediction equation (GMPE) for the average horizontal component of peak ground acceleration (PGA), peak ground velocity (PGV), and 5% damped acceleration response spectra at periods ranging from 0.033 to 8.0 s (SA (T = 0.033–8.0 s)) is introduced. This GMPE considers multiple influencing factors such as magnitude and distance saturation effect, geometric attenuation, style-of-faulting, hanging-wall effect, linear/nonlinear site response, and anelastic attenuation. The residual evaluation and median ground motion are presented. The predicted ground motions using the new GMPE are compared with predictions from the GMPE in western China and five NGA-West2 GMPEs, and the observed ground motions of strong earthquakes which occurred in southwest China. The results show that the proposed GMPE can better reflect the influence of the earthquake source characteristic, propagation media, site effect on the ground motion attenuation characteristic in southwest China, and works well versus independent strong motion data of earthquakes in southwest China, and well reflects the general feature of ground motions for the Wenchuan and Lushan earthquakes that is rich at short-period and weak at long-period. The new GMPE shows outstanding performance estimating the horizontal ground motion of the earthquakes in southwest China for MW 4.2–7.9 (related to style-of-faulting) and Rrup = 10–200 km, at sites with VS30 = 140–1130 m/s.
... Two alternative attenuation relations were used in the current study to predict the ground motion on bedrock in terms of M w scale. The attenuation relations of García et al. (2005) and Abrahamson and Silva (1997) were used to model the ground motion in the seismic sources located inside and outside Kuwait, respectively. ...
... Figure 10 illustrates the effect of the change of the ground motion attenuation relations for the seismic sources in the first model on the seismic hazard. The hazard calculated using the attenuation relations of the first model shows higher values than those calculated by changing the attenuation relation of Abrahamson and Silva (1997) to Youngs et al. (1997). This variation in the hazard is slight at short periods and increases with the spectral periods. ...
... This variation in the hazard is slight at short periods and increases with the spectral periods. This is because the contribution to the hazard from shallow crustal earthquakes described by Abrahamson and Silva (1997) relation at these cities is greater than that of large earthquakes ...
Article
Urban development and construction of high-rise buildings in Kuwait have recently increased precipitately. For this reason, creating a seismic code for residential areas in Kuwait has become essential. This exertion to acquire precious results is the first step toward creating a unified earthquake code for the residential areas in the State of Kuwait. In this study, more details of local seismic activity were considered, as well as regional seismic activity, as a result of Kuwait’s proximity to the famous Zagros belt in Iran. Unified historical and instrumental catalogs on earthquake were compiled for Kuwait and neighboring regions. Influential seismic sources have been identified. Alternative seismotectonic models have been principally created. Recurrence coefficients and maximum earthquake expected from each seismic source were fundamentally considered, taking into account the epistemic uncertainty. The uniform hazard spectra for six Kuwaiti governorates were calculated using deterministic hazard technique. To reduce uncertainty, a sensitivity analysis was conducted for all six Kuwaiti governorates using seismotectonic pattern, earthquake attenuation models, and maximum expected earthquake. The priceless outcome of this study can be used by the Kuwaiti Public Authority for Housing Welfare to create a seismic code for buildings in Kuwait.
... In contrast, the maximum vertical peak velocities remain on the hanging-wall side of the faults, and the amplitude and spatial shape of the peak velocities is nearly independent of dip ( Fig. 1d and e). These results are profoundly different from that predicted by ground-motion relations, particularly the recommendations of Abrahamson and Silva (1997) and Somerville et al. (1997), who ascribe the dominant amplification of horizontal ground motions associated with directivity to the hanging wall. Abrahamson and Silva (1997) and Somerville et al. (1997) did not have a statistically significant sample of near-fault normal-faulting ground motions. ...
... These results are profoundly different from that predicted by ground-motion relations, particularly the recommendations of Abrahamson and Silva (1997) and Somerville et al. (1997), who ascribe the dominant amplification of horizontal ground motions associated with directivity to the hanging wall. Abrahamson and Silva (1997) and Somerville et al. (1997) did not have a statistically significant sample of near-fault normal-faulting ground motions. Consequently, there is no empirical basis to use the directivity corrections Table 1 Homogeneous Half-Space Dynamic Rupture Grid Parameters of Abrahamson and Silva (1997) and Somerville et al. (1997) for normal faulting. ...
... Abrahamson and Silva (1997) and Somerville et al. (1997) did not have a statistically significant sample of near-fault normal-faulting ground motions. Consequently, there is no empirical basis to use the directivity corrections Table 1 Homogeneous Half-Space Dynamic Rupture Grid Parameters of Abrahamson and Silva (1997) and Somerville et al. (1997) for normal faulting. Further, their predictions for reverse faulting are dominated by ground motions recorded from reverse faults with dips < 50°. ...
Article
Full-text available
We investigate the influence of fault dip (35°-60°) and crustal velocity heterogeneity on rupture dynamics and near-fault ground motions from normal-and reverse-faulting. The same initial conditions were used, except for the direction of initial shear stress, in each dynamic rupture calculation. We used two 3D elastic finite-element approaches that employ split nodes for the computations. In homogeneous and weakly heterogeneous half-spaces with faults dipping ≲50°, maximum fault-normal peak velocities occurred on the hanging wall. However, for fault dips ≳50°, maximum fault-normal peak velocities occurred on the footwall. Bilateral and unilateral rupture simulations in weakly heterogeneous media found that reverse-faulting slip velocities (frequency band 1-3.5 Hz) were on average 39% larger than those during normal faulting. However, on average reverse-faulting slip velocities were only 16% larger than normal-faulting slip velocities for frequencies < 1 Hz. This suggests that normal-faulting ground motions may have peak spectral accelerations at distinctly lower frequencies than reverse-faulting ground motions. Normal faults often juxtapose a low-velocity hanging-wall sedimentary basin against relatively stiff footwall rocks. A 3D velocity model was constructed with a thick (several kilometers) low-velocity basin with a strong shear-wave velocity contrast (factor of 3) across a fault dipping 55°. While the strong lateral velocity contrast reduced normal-faulting fault-normal peak velocities on the footwall, substantial (0:5-1 m=sec) fault-normal peak velocities remained on the footwall. Meanwhile even larger fault-normal peak velocities occurred on the more compliant hanging wall. These results indicate that simple amplitude parameterizations based on the hanging wall and/or footwall and the fault normal and/or fault parallel currently used in ground motion prediction relations may not be appropriate for some faults with dips > 50°.
... Ground Motion Models (GMMs) predict different ground motion intensity metrics (e.g., peak ground acceleration, peak ground velocity, Fourier amplitude spectra, duration, ground shaking time history, etc.) by constructing a model to transform a finite number of parameters to the observed ground motion data (Anderson and Brune, 1999;Abrahamson and Silva, 1997). The GMMs are parameterized based on a simplified representation of the source, path, and site effects, as explained below: ...
... The selected accelerograms are assumed to be representative of ground shaking for future events. The GMPEs estimate the intensity level of ground motion by using regression analysis over a set of parameters that are explained above (Anderson and Brune, 1999;Abrahamson and Silva, 1997). In recent years, different GMPEs have been proposed for different applications (region-specific, site-specific, and region-and site-specific models). ...
Thesis
Seismology, like many scientific fields, e.g., music information retrieval and speech signal pro- cessing, is experiencing exponential growth in the amount of data acquired by modern seismo- logical networks. In this thesis, I take advantage of the opportunities offered by "big data" and by the methods developed in the areas of music information retrieval and machine learning to predict better the ground motion generated by earthquakes and to study the properties of the surface layers of the Earth. In order to better predict seismic ground motions, I propose two approaches based on unsupervised deep learning methods, an autoencoder network and Generative Adversarial Networks. The autoencoder technique explores a massive amount of ground motion data, evaluates the required parameters, and generates synthetic ground motion data in the Fourier amplitude spectra (FAS) domain. This method is tested on two synthetic datasets and one real dataset. The application on the real dataset shows that the substantial information contained within the FAS data can be encoded to a four to the five-dimensional manifold. Consequently, only a few independent parameters are required for efficient ground motion prediction. I also propose a method based on Conditional Generative Adversarial Networks (CGAN) for simulating ground motion records in the time-frequency and time domains. CGAN generates the time-frequency domains based on the parameters: magnitude, distance, and shear wave velocities to 30 m depth (VS30). After generating the amplitude of the time-frequency domains using the CGAN model, instead of classical conventional methods that assume the amplitude spectra with a random phase spectrum, the phase of the time-frequency domains is recovered by minimizing the observed and reconstructed spectrograms. In the second part of this dissertation, I propose two methods for the monitoring and characterization of near-surface materials and site effect analyses. I implement an autocorrelation function and an interferometry method to monitor the velocity changes of near-surface materials resulting from the Kumamoto earthquake sequence (Japan, 2016). The observed seismic velocity changes during the strong shaking are due to the non-linear response of the near-surface materials. The results show that the velocity changes lasted for about two months after the Kumamoto mainshock. Furthermore, I used the velocity changes to evaluate the in-situ strain-stress relationship. I also propose a method for assessing the site proxy "VS30" using non-invasive analysis. In the proposed method, a dispersion curve of surface waves is inverted to estimate the shear wave velocity of the subsurface. This method is based on the Dix-like linear operators, which relate the shear wave velocity to the phase velocity. The proposed method is fast, efficient, and stable. All of the methods presented in this work can be used for processing "big data" in seismology and for the analysis of weak and strong ground motion data, to predict ground shaking, and to analyze site responses by considering potential time dependencies and nonlinearities.show less
... In this Section, for a reader's convenience, we have only summarized the main basis of RVT theoretical approach in obtaining response spectrum. Details can be found in extensive RVT literature: Cartwright and Longuet-Higgins (1956); Hanks and McGuire (1981); Boore (1983Boore ( , 2003; Silva and Lee (1987), Silva et al. (1997); Rathje (2009, 2013); Bora et al. (2016). Boore (1983Boore ( , 2003 described in detail the RVT methodology approach to predict the response spectral ordinates of an SDOF system using FAS of the ground and ground analysis is the prediction of the peak value of the ground motion from the FAS and its duration through Parseval's theorem and extreme value statistics (e.g., Vanmarcke and Lai, 1980;Hanks and McGuire, 1981;Boore, 1983Boore, , 2003. ...
... Empirical equations for predicting the duration of ground motion are based upon seismological parameters as proposed by Abrahamson and Silva (1997). Kempton and Stewart (2006) proposed an empirical equation for D gm that is scaled with respect to magnitude and distance. ...
Article
In the wake of recent 2020 ML ≥ 5.5 earthquakes in Croatia, Zagreb ML5.5 and Petrinja ML6.2, the insufficient instrumental network as well as the lack of regional ground motion prediction equation (GMPE) were identified as the drawbacks of our engineering community. The former is related to the quality definition of active seismicity (most of the instruments are installed in the southern part of Croatia with fewer installed around Zagreb in the northwestern part of Croatia), and the latter is related to the proper number of strong motion recordings. In Croatia, there is a sparse database of ground motion recordings for moderate earthquakes which makes a well-designed ground motion selecting procedure hardly achievable. Following this, strong motion BSHAP database for empirical estimation of the response spectrum based on Fourier amplitude spectrum and the ground motion duration using Random Vibration Theory approach adjusted to source, propagation, and local site conditions was used. Regionally adjusted ground motion model estimations for the ML6.2 Petrinja 2020 earthquake scenario are comparable with the previously published GMPEs models for this part of Europe and for the Western part of North America. However, model-to-model variability and uncertainties in local GMPE exceeded those of global GMPEs and are influenced by statistically less stable and more limited datasets. Model is applicable for magnitudes up to Mw6.5 and Joyner-Boore distances up to 200 km with usable frequency range between 0.4 and 33 Hz. The presented model is a step forward toward performing hybrid-empirical seismic hazard studies in areas with sparse ground motions such as the region of Croatia.
... CHEEP did not include Chiou and Youngs (2014) as one of its in-built GMPEs so stochastic models for this GMPE are also not available in the form required by this software. Because the software to repeat Scherbaum et al. (2006)'s inversion process is not available, the stochastic models provided in CHEEP for the WNA GMPEs of Abrahamson and Silva (1997) and Boore et al. (1997) were both used as proxies for the unavailable stochastic models for Chiou and Youngs (2014). By examining the match between the predictions from these stochastic models and the Chiou and Youngs (2014) GMPE over a wide range of magnitudes and distances it was confirmed that these stochastic models are suitable for the HEM. ...
... By examining the match between the predictions from these stochastic models and the Chiou and Youngs (2014) GMPE over a wide range of magnitudes and distances it was confirmed that these stochastic models are suitable for the HEM. In addition, similar backbone GMMs were obtained by using both the stochastic models for Abrahamson and Silva (1997) and that for Boore et al. (1997). As the backbone GMM was only being used for comparisons and not for the actual PSHA, and because small misfits between empirical and stochastic host models have previously been shown to be relatively unimportant (Campbell 2003;Douglas et al. 2006), it was decided that the use of these approximate stochastic models was sufficient for our purposes. ...
Article
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A key task when developing a ground-motion model (GMM) is to demonstrate that it captures an appropriate level of epistemic uncertainty. This is true whether multiple ground motion prediction equations (GMPEs) are used or a backbone approach is followed. The GMM developed for a seismic hazard assessment for the site of a UK new-build nuclear power plant is used as an example to discuss complementary approaches to assess epistemic uncertainty. Firstly, trellis plots showing the various percentiles of the GMM are examined for relevant magnitudes, distances and structural periods to search for evidence of “pinching”, where the percentiles narrow excessively. Secondly, Sammon’s maps, including GMPEs that were excluded from the logic tree, are examined to check the spread of the GMPEs for relevant magnitudes and distances in a single plot. Thirdly, contour plots of the standard deviation of the logarithms of predicted ground motions from each branch of the logic tree (σµ) are compared with plots drawn for other relevant hazard studies. Fourthly, uncertainties implied by a backbone GMM derived using Campbell (2003)’s hybrid stochastic empirical method are compared to those of the proposed multi-GMPE GMM. Finally, the spread of the percentile of hazard curves resulting from implementing the GMM are examined for different return periods to check whether any bands of lower uncertainty in ground-motion space result in bands of lower uncertainty in hazard space. These five approaches enabled a systematic assessment of the level of uncertainty captured by the proposed GMM.
... In this Section, for a reader's convenience, we have only summarized the main basis of RVT theoretical approach in obtaining response spectrum. Details can be found in extensive RVT literature: Cartwright and Longuet-Higgins (1956); Hanks and McGuire (1981); Boore (1983Boore ( , 2003; Silva and Lee (1987), Silva et al. (1997); Rathje (2009, 2013); Bora et al. (2016). Boore (1983Boore ( , 2003 described in detail the RVT methodology approach to predict the response spectral ordinates of an SDOF system using FAS of the ground and ground analysis is the prediction of the peak value of the ground motion from the FAS and its duration through Parseval's theorem and extreme value statistics (e.g., Vanmarcke and Lai, 1980;Hanks and McGuire, 1981;Boore, 1983Boore, , 2003. ...
... Empirical equations for predicting the duration of ground motion are based upon seismological parameters as proposed by Abrahamson and Silva (1997). Kempton and Stewart (2006) proposed an empirical equation for D gm that is scaled with respect to magnitude and distance. ...
Poster
The most seismically active regions in Croatia are the coastal region and the north-western part of Croatia, regions that have numerous cultural heritage sites. Therefore, it is important to estimate seismic risk for cultural heritage sites and to develop procedures for seismic risk assessment. These are the goals of the research project Seismic Risk Assessment of Cultural Heritage Buildings in Croatia (SeisRICHerCRO) funded by the Croatian Science Foundation. The targeted locations of the project are Trakošćan Castle, the Cathedral of St. Jacob in Šibenik and the old city centre of Dubrovnik. The project has many objectives: investigation of seismicity according to the compiled earthquake catalogue, determination of local site characteristics, numerical analysis of local seismic site response, determination of dynamic characteristics of selected buildings, seismic hazard assessment, seismic vulnerability and risk assessment and finally coordination and administration. Microtremor measurements were carried out at all three targeted locations: Trakošćan Castle (approx. 0.1 km2, 36 measurements), in the proximity of the Cathedral of St. Jacob in Šibenik (approx. 0.15 km2, 108 measurements) and in the old city centre of Dubrovnik (approx. 0.2 km2, 115 measurements). Based on individual microtremor measurements, maps of fundamental site frequencies were derived. Following the empirical relationship between resonance site frequency, bedrock depth and Vs30 for Croatia, maps of average shear wave velocity in the upper 30 m (Vs30) and bedrock depth (H800- depth of the bedrock formation identified by shear wave velocity VS ≥ 800 m/s) were also derived. Presented maps can help to distinguish potentially dangerous seismic zones in the all three targeted locations: a) soil-structure (building) resonance at fundamental site frequencies, b) Vs30 is important for Eurocode 8 classification, and c) bedrock depths are important for numerical site response analysis for the estimation of site amplification. Comprehensive seismic microzonation maps incorporating seismic site amplification data provide input data for earthquake-resistant designs as well as the construction and reconstruction of important buildings and are also useful for urban planning that utilises spatial master plans.
... The first set of seismic sources comprised four area-type sources of spatially uniform seismicity, whereas the second set considered the total seismicity in each area source to be associated with a selected single fault in the source zone. The three GMPEs used are from Abrahamson and Silva, 30 Sadigh et al., 31 and Boore and Atkinson. 32 The bedrock-level uniform hazard response spectra at 449 sites throughout the NCT area at which detailed geotechnical investigations had been carried out to define the soil columns were used to generate compatible acceleration time-histories, which were then propagated to the surface using 1D shear wave propagation with an equivalent linear method of solution. ...
... The common weaknesses of most existing studies are that (i) they use empirical scaling equations not based on strong motion recordings in India, and hence are inconsistent with local geological effects on attenuation and ignore regional biases in earthquake magnitude determination; (ii) work only with the PGA, which, when combined with spectral shapes in design codes, give biased design amplitudes at intermediate and long periods of vibration; (iii) completely ignore the effects of geological site conditions and use soil site condition parameter V S, 30 , which has been demonstrated to be a statistically insignificant proxy for a site parameter meant to characterize local site amplification. 33 The present study has developed improved high-resolution microzoning maps of the Delhi NCT and adjacent areas using refined input seismicity by updating the earthquake catalog and improving the smoothing process to normalize for the uncertainty in defining the seismic source-zone boundaries as described in Part-I of the paper. ...
Article
We present seismic microzonation maps of New Delhi, India, using the probabilistic seismic hazard analysis (PSHA) method with input seismic activity parameters estimated in Part‐I of this two‐part paper. Our calculations required three different attenuation equations for amplitude scaling of strong ground motion from three principal contributing sources: the National Capital Region (NCR), Northwestern Himalaya (NWH), and the Hindu Kush subduction (HKS). We show that uniform hazard spectral (UHS) amplitudes are dominated only by the local seismicity in the NCR at high frequencies beyond about 2 Hz. For intermediate and long periods, UHS amplitudes are dominated by contributions from the NWH and HKS earthquakes. Our results show that specifying strong motion amplitudes for use in engineering design by means of peak ground acceleration can lead to serious errors for buildings higher than four to five stories and hence should not be used. Our results also show that the shape of design spectra must depend on the nature of contributing earthquake sources, their relative activity, potential to create large magnitudes, and geographical placement relative to the site of interest, and thus a standard design‐spectrum shape cannot satisfy all these requirements. We use local geological site condition parameters directly in all calculations and present hazard maps for three different soil site conditions (“rock,” stiff soil sites, and deep soil sites). Thus, the user can extract the UHS amplitudes of pseudo relative velocity spectra at any site in the National Capital Territory by experimentally determining the local soil site conditions and then applying the corresponding maps shown in this paper. Seismic microzonation map showing the Uniform Hazard Spectra of Pseudo Relative Velocity (PSV) at 13 periods in the New Delhi metropolitan area, in India, at “rock” soil sites, = 0, for 10% probability of being exceeded during exposure of 50 years.
... A logic tree approach was used to combine their effects with an equal weight given to each of the GMPEs as shown in Fig. 8. In the present work, six GMPEs were chosen as proposed by (1) Abrahamson and Silva (1997), (2) Sadigh et al. (1997), (3) Campbell (2003), (4) Atkinson and Boore (2006), (5) Raghukanth and Iyengar (2007), and (6) Iyengar et al. (2010). ...
... The six GMPEs used in the present study were derived for various parts of the world for intra-plate and active shallow crustal earthquakes. For example, the GMPE given by Abrahamson and Silva (1997) is for worldwide shallow crustal earthquakes. Atkinson and Boore (2006) developed a GMPE for crustal intra-plate earthquakes for eastern North America. ...
Article
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The Indian peninsular region has witnessed moderate to large earthquakes in the recent past. The present work demonstrates probabilistic seismic hazard assessment at the bedrock level using six ground-motion prediction equations with a logic tree approach considering Odisha state as a case study. Regional rupture characteristics are established for the tectonic features of the study region. Uniform hazard response spectra are computed for district places. Seismic hazard results are disaggregated for Bhubaneswar, the capital city of Odisha. The results have shown the distribution of seismicity in the state is not in sync with the seismic zone map provided by the Indian code.
... However, it has possible to determine uncertain acceleration absorbing capacity of the ground by applying various statistical logics although this process does not contain any functional issues such as material, geometric, chemical and mechanical properties of soil medium. Seismic acceleration was evaluated from the attenuation relationships whereas predicting excitation was the function of epicentral distance and focal depth [2]. ...
Article
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Earthquake is an uncertain phenomena, which occurs suddenly in any location in the world that's why, prediction of its hazardous effect has difficult without statistical study whereas probability of spectral deformation of ground is evaluated by the hypothesis analysis and this distortion disturbs engineering structures, lifelines etc. Therefore, in this study, probable occurrence of seismic acceleration induced spectral ground movement is evaluated by the statistical study for various locations of Bangladesh while five second seismic shock is considered for time series plot of excitations. So, proposed logic is that spectral ground movement has not hampered lifeline structures until peak seismic acceleration has reached around one percent of its coordinate value that's why, two sided hypothesis test is performed to confirm this brief. Rejection of null hypothesis is the strong evidence for the small settlement of ground and also, it indicates less hazard of structures although some amount of damages might be occur during earthquake.
... frontiersin.org and f hc of the illustrated recording in Figure 3A are 1.02 and 25 Hz, and the spectra are usable (gray shaded areas) at a frequency range from 1.25f hc to f lc /1.25 (Abrahamson et al., 1997). The number of usable spectra at each frequency point are shown in Figure 3B. ...
Article
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In an effort to investigate the attenuation characteristics and site effects in eastern Guangdong, 659 strong-motion recordings received by 27 stations were selected for spectral analysis to separate path attenuation, site effects and source spectra. The path attenuation curves are generally close to the simplest form of distance decay described by R −0.5 , and decays the slowest at a frequency of 4 Hz. We decomposed the path attenuation into a combination of geometric spreading and inelastic attenuation. The geometric spreading R −0.15 exhibits a slower distance decay at local distances, indicating that the seismic energy close to the epicenter is not easily dissipated. The quality factors were regressed as Q s ( f ) = 114.81 f .922 in the frequency range .9–20 Hz, lower than those reported for the whole Guangdong region, indicating stronger anelastic attenuation in eastern Guangdong. The site responses in eastern Guangdong show a strong correlation with geological and geotechnical characterization. The stations located in the central mountains have higher predominant frequencies (>10 Hz) accompanied by smaller site amplifications. Larger site amplification is in the southeast coastal area (i.e., Shantou area), where the surface is covered with a thicker layer of soft soil and the predominant frequency of site is relatively low (∼2 Hz). The far-field earthquake will cause greater vibration and damage to this area.
... This information pertains to earthquake events (Mw, R and ) that are most likely to produce a specific target spectral value over a particular period. The value defines how much larger a target spectral value at a given period is compared to the predictions of a GMM (GMM of Abrahamson and Silva [77] is used in the original study [48]). A fundamental principle of CMS is that the spectral value obtained from deaggregation of a given period does not necessarily apply to other periods. ...
Article
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The structural response of buildings to earthquake shaking is of critical importance for seismic design purposes. Research on the relationship between earthquake ground motion intensity, building response, and seismic risk is ongoing, but not yet fully conclusive. Often, probability demand models rely on one ground motion intensity measure (IM) to predict the engineering demand parameter (EDP). The engineering community has suggested several IMs to account for different ground motion characteristics, but there is no single optimal IM. For this study, we compile a comprehensive list of IMs and their characteristics to assist engineers in making an informed decision. We discuss the ground motion selection process used for dynamic analysis of structural systems. For illustration, we compute building responses of 2D frames with different natural period subjected to more than 3500 recorded earthquake ground motions. Using our analysis, we examine the effects of different structural characteristics and seismological parameters on EDP-IM relationships by applying multi-regression models and statistical inter-model comparisons. As such, our results support and augment previous studies and suggest further improvements on the relationship between EDP and IM in terms of efficiency and sufficiency. Finally, we provide guidance on future approaches to the selection of both optimal intensity measures and ground motions using newer techniques.
... The shallow crust earthquakes correspond to shallow earthquakes occurring within the North American plate. Model attenuations used were as follows: Abrahamson and Silva (1997) (Ordaz et al., 2012), which allows the inclusion of the site effects in the calculation of seismic hazard through amplification factors (ratios spectra response), which depend on the location of the site, the structural period and the level of soil movement. ...
... An example of ϵ-based spectral modification is illustrated in Figure 5a using Abrahamson and Silva [57]'s attenuation model to compute ϵ and a sample record from FEMA P695. As seen in this figure, ϵ is computed such that the earthquake's spectrum crosses the dashed lines (scaled mean attenuation) at T 1 = 0.94 s for the four-story frame or T 2 = 1.8 s for the eight-story frame. ...
Article
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Uncertainty quantification is a challenging task in the risk-based assessment of buildings. This paper aims to compare reliability-based approaches to simulating epistemic and aleatory randomness in reinforced concrete (RC) frames. Ground motion record-to-record variability is combined with modeling uncertainty which is propagated by either an approximate first-order second-moment or Latin Hypercube sampling methods. The sources of uncertainties include post-yield hardening stiffness, cyclic energy dissipation capacity, and the plastic and post-cap rotation capacities of beam-column elements. All nonlinear simulations are performed with two methods: detailed incremental dynamic analysis, and the simplified SPO2IDA. The combination of all parametric methods is used to analyze two RC frames (four-story and eight-story), and the results are further post-processed to drive fragility functions. Several assumptions were investigated in curve fitting, functional form, uncertainty, and confidence intervals. The results indicate the importance of modeling uncertainty in higher seismic intensity levels. While there is a negligible difference in fragility curve fitting, its variability due to optimal intensity measure parameters is dominant.
... The latter are considered to be independent, normal distributed variables with their own variances. The inter-and intra-event components of the total uncertainty represent the earthquake-to-earthquake variability and the variability among observations within a single event, respectively (see Abrahamson & Silva 1997;Atik et al. 2010;Baltay et al. 2017). The mixed model allows us to understand the respective contribution of aleatory and epistemic uncertainties, which can be accounted individually to improve the ground-motion models. ...
Article
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Ground shaking, whether it is due to natural or induced earthquakes, has always been a matter of concern since it correlates with structural/non-structural damage and can culminate in human anxiety. Industrial activities such as water injection, gas sequestration and waste fluid disposals, promote induced seismicity and consequent ground shaking that can hinder ongoing activities. Therefore, keeping in mind the importance of timely evaluation of a seismic hazard and its mitigation for societal benefits, the present study proposes specifically designed ground-motion prediction equations (GMPEs) from induced earthquakes in the St. Gallen geothermal area, Switzerland. The data analysed in this study consist of 343 earthquakes with magnitude −1.17 ≤ ML, corr ≤ 3.5 and hypocentral distance between 4 and 15 km. The proposed study is one of the first to incorporate ground motions from negative magnitude earthquakes for the development of GMPEs. The GMPEs are inferred with a two-phase approach. In the first phase, a reference model is obtained by considering the effect of source and medium properties on the ground motion. In the second phase the final model is obtained by including a site/station effect. The comparison between the GMPEs obtained in the present study with GMPEs developed for the other induced seismicity environments highlights a mismatch that is ascribed to differences in regional seismic environment and local site conditions of the respective regions. This suggests that, when dealing with induced earthquakes, GMPEs specific for the study should be inferred and used for both monitoring purposes and seismic hazard analyses.
... Through these equations, the ground motion at any location can be estimated if magnitude, distance, and other parameters are known. GMPEs pertinent to the current tectonic region with shallow earthquakes such as Abrahamson and Silva (1997), Iyengar and Raghukanth (2004), Amiri et al. (2007), and Tabassum and Ansary (2020) were used in this study to determine PGA at the bedrock. Finally, for the assessment of liquefaction at the study site, the PGA value needs to be determined at the surface. ...
Article
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This study carries out a site response and liquefaction analysis of a new international airport site in Sylhet, in the northeastern part of Bangladesh. The site is situated in an area near the Himalayan thrust which is home to numerous large earthquakes, including the 1869 Cachar, the 1897 Great Indian, 1918 Srimangal, and 1923 Durgapur, and many other relatively smaller earthquakes. Hence, in view of the past seismicity and significance of the power plant site, a seismic investigation was performed in the seismic control region within a radius of 300 km from the center of the plant site. The peak ground acceleration (PGA) value at the bedrock level for a return period of 475 years for the site was estimated to be 0.30 g. For the last few decades, the coefficients of a site have generally been estimated from the mean shear-wave velocity for the top 30 m of a location. The surface PGA of a location is equal to the product of the bedrock PGA and the estimated site coefficient. If the bedrock is located more than 30 m below the ground, the site effect estimated from Vs30 cannot appropriately represent the site coefficient. For the study site, the bedrock is approximately 150 m below the ground. For loose sedimentary deposits of this site, the site coefficient based on Vs30 used to assess the PGA on the surface is not suitable. In this research, a site amplification factor based on Vs30, equivalent-linear, and nonlinear methods was used to estimate the PGA at the surface of the site. In this site, the susceptibility to liquefaction was estimated utilizing 61 boreholes having SPT-N values at intervals of 1.5 m from the surface to a depth of 20 m. Here, liquefaction susceptibility was assessed by applying Seed and Idriss’ simplified method, Japanese method, and Chinese method. The estimated liquefaction potential index (LPI) contours show that 80–90% of the total area is highly susceptible to liquefaction and the rest of the area has low susceptibility.
... This agreement may suggest that either the spectra 530 produced by large events are dominated by frequencies ≤1.5 Hz (as in our model setup), or that 531 the higher frequencies are rapidly attenuated. Our model results are within a similar range to those 532 of the previous models of Harbindu et al. [2014], who calculate ground motion model PGAs on the 533 order of 1 ms −2 to 10 ms −2 for the neighbouring Garhwal Himalaya, following the empirical rules 534 of Abrahamson and Litehiser [1989], Singh et al. [1996], Abrahamson and Silva [1997], Boore and 535 Atkinson [2008], and Sharma et al. [2009]. ...
Article
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Large thrust faults accommodate the convergence between India and Tibet along the southern margin of the Himalaya and have a history of producing great earthquakes that cause widespread damage. Along most parts of the Himalaya, there is geomorphological evidence that these thrusts can rupture to the surface in M w >8 earthquakes. However, in the Himalayan state of Jammu & Kashmir (NW India), the thrust faults are blind and large-scale folding is the only expression of active deformation at the surface, making it difficult to assess the seismic hazard in this region. In this paper, we use field, satellite, and seismological observations to determine the fault geometry in Jammu & Kashmir. We then estimate the ground motions from potential earthquakes in the region using models of the seismic wavefield that would be generated if the thrust fault beneath Jammu & Kashmir were to rupture. We find that earthquakes that rupture the buried, shallow part of the locked Main Himalayan Thrust could generate peak ground velocities that are >3 times larger than earthquakes of the same magnitude on its deeper portions. We also model the ground motions that would result from the thrust fault geometries representative of different parts of the Himalayan arc. These simulations show that even seemingly minor variations in the shallow fault geometry can lead to large differences in the expected ground motions, highlighting the importance of accurately determining the shallow geometry of thrust faults along the margins of mountain ranges for estimating seismic hazard.
... After band-pass filter, the numbers of usable spectra at frequencies from 0.25 to 20 Hz were plotted, as shown in Fig. 3c. The FAS is usable at a frequency range from 1.25f lc to f hc /1.25 (Abrahamson & Silva, 1997). We further used the following criteria to select the processed recordings for spectral decomposition: (1) M C 3.0, (2), hypocentral distance B 100 km in order to reduce the contamination from the coda wave to the extracted S wave, (3) maximum horizontal PGA \ 100 cm/s 2 in order to avoid the potential nonlinear soil behavior as much as possible, and (4) each selected event should be recorded by at least four stations, each of which should collect at least four records meeting the given criteria (1), (2), and (3). ...
Article
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On 21 May 2021, an M 6.4 earthquake occurred in Yangbi county, west of Yunnan Province, China. The Yangbi seismic sequence was initiated on 18 May and reached its climax as the occurrence of the M 6.4 mainshock. It was a typical foreshock-mainshock-aftershock sequence. A total of 1043 strong-motion recordings during 44 events from this sequence were selected and utilized for the spectral decomposition to separate the path attenuation and source spectra. The path attenuation curves are overall close to the simplest distance decay form described by R−1. The path attenuations were further represented by the combination of the geometric spreading and anelastic attenuation. Geometric spreading of R−0.37 was retrieved, indicating slower distance decay at local distances. The larger area close to the epicenter tends to undergo strong ground shaking. The quality factors obtained were regressed as Qs(f) = 64.27f 0.76 in the frequency range of 0.25–20 Hz, lower than those reported for the whole Yunnan region, indicating faster attenuation at large distances in the study region. The seismic moments, corner frequencies, and stress drops were estimated from the inverted source spectra. The stress drops for the Yangbi seismic sequence were mainly in the range of 0.5–3.0 MPa. The mainshock had the largest stress release (~ 2.7 MPa). The strong foreshocks and aftershocks with Mw ≥ 5.0 had higher stress drops (~ 1.5–2.5 MPa) than those of small events with Mw < 5.0 (~ 0.1–1.5 MPa). We inferred that the strong foreshocks and aftershocks with high stress releases may not rupture the same fault activated by the mainshock, while they may occur in various fault branches.
... Adicionalmente para nuestro estudio, se utilizaron dos leyes de atenuación, la ley para sismos corticales propuesta por Abrahamson & Silva (1997) y la ley de Atkinson & Boore (2006). El uso de dichas leyes se realizó de acuerdo con lo indicado en la tabla 3. ...
Conference Paper
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En México es posible identificar dos grandes regiones por su importante sismicidad: la región que se localiza a lo largo de la costa del Pacífico (dirección este-oeste) cubriendo los estados de Jalisco, Colima, Michoacán, Guerrero, Oaxaca y Chiapas, y la región del Golfo de California que incluye a la península de Baja California. En esta última región los mecanismos de fallas sísmicas son en su mayoría de tipo lateral derecho, mientras que en la región de la costa del Pacífico los mecanismos de falla son dominantemente de subducción. Por otra parte, los registros de la sismicidad son muy relevantes en los estudios de peligro sísmico, los cuales a su vez son de gran importancia en el ámbito de la ingeniería sísmica. En la presente investigación se estudió el peligro sísmico regional del estado de Sinaloa con énfasis en la región de Los Mochis, ubicada en el municipio de Ahome, Sinaloa. Además, se determinó la aceleración en roca para distintos periodos de retorno (Tr = 475, 975 y 2475 años). Adicionalmente, se compararon los resultados de aceleración espectral obtenidos con las aceleraciones espectrales que se proponen en los espectros de peligro uniforme en el Manual de Obras Civiles de la CFE de 2015 (manual de común aplicación en Los Mochis por la ausencia de normativa local). Se observó que el peligro sísmico de Los Mochis fue muy sensible a un ajuste en la geometría de la más importante fuente sísmica, para el peligro de dicha ciudad. Particularmente, se compararon valores de PGA para 475 años, y se observó que el incremento en el valor de PGA debido a dicho ajuste fue de aproximadamente 35%. ABSTRACT. In Mexico, it is possible to identify two large regions due to their significant seismicity: the region that is located along the Pacific coast (east-west direction), covering the states of Jalisco, Colima, Michoacán, Guerrero, Oaxaca, and Chiapas, and the Gulf of California region that includes the Baja California peninsula. In the latter region, the seismic failure mechanisms are mostly of the right lateral type, while in the Pacific coast region, the failure mechanisms are predominantly subduction. On the other hand, seismicity records are very relevant in seismic hazard studies, which are of great importance in the field of seismic engineering. In this research, the regional seismic hazard of the state of Sinaloa was studied with emphasis on the Los Mochis region, located in the municipality of Ahome, Sinaloa. Also, the acceleration in rock was determined for different return periods.
... CHEEP did not include Chiou and Youngs (2014) as one of its in-built GMPEs so stochastic models for this GMPE are also not available in the form required by this software. Because the software to repeat Scherbaum et al. (2006)'s inversion process is not available, the stochastic models provided in CHEEP for the WNA GMPEs of Abrahamson and Silva (1997) and Boore et al. (1997) were both used as proxies for the unavailable stochastic models for Chiou and Youngs (2014) and similar backbone GMMs obtained. By examining the match between the predictions from these stochastic models and the Chiou and Youngs (2014) GMPE over a wide range of magnitudes and distances it was con rmed that these stochastic models are suitable for the HEM. ...
Preprint
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A key task when developing a ground-motion model (GMM) is to demonstrate that it captures an appropriate level of epistemic uncertainty. This is true whether multiple ground motion prediction equations (GMPEs) are used or a backbone approach is followed. The GMM developed for a seismic hazard assessment for the site of a UK new-build nuclear power plant is used as an example to discuss complementary approaches to assess epistemic uncertainty. Firstly, trellis plots showing the various percentiles of the GMM are examined for relevant magnitudes, distances and structural periods to search for evidence of “pinching”, where the percentiles narrow excessively. Secondly, Sammon’s maps, including GMPEs that were excluded from the logic tree, are examined to check the spread of the GMPEs for relevant magnitudes and distances in a single plot. Thirdly, contour plots of the standard deviation of the logarithms of predicted ground motions from each branch of the logic tree (σ µ ) are compared with plots drawn for other relevant hazard studies. Fourthly, uncertainties implied by a backbone GMM derived using the Campbell (2003)’s hybrid stochastic empirical method are compared to those of the proposed multi-GMPE GMM. Finally, the spread of the percentile of hazard curves resulting from implementing the GMM are examined for different return periods to check whether any bands of lower uncertainty in ground-motion space resulted in bands of lower uncertainty in hazard space. These five approaches enabled a systematic assessment of the level of uncertainty captured by the proposed GMM.
... The percentage of the stations with an error > 1 is written in the panel definitions for the fault distance to consider the fault finiteness, as shown in Fig. 2. Joyner and Boore (1981) defined the shortest distance between a site and surface projection of the fault plane as the Joyner-Boore distance (R JB ). The rupture distance (R RUP ) is the closest distance between a site and the three-dimensional rupture plane (Abrahamson and Silva 1997). A high-frequency ground motion is sensitive to R JB but less sensitive to the dip of the fault plane (Yamada et al. 2007). ...
Article
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We present a methodology for estimating fault geometry and utilizing the distance to the fault for the shaking estimation to improve the accuracy of real-time shaking estimates for large earthquakes. Most of the earthquake early warning system currently estimates the seismic intensity with the ground-motion prediction equations (GMPE) as a function of the hypocenter distance. However, using the fault distance computed from a finite source model can improve the accuracy of the shaking intensity estimation for large earthquakes. This study proposes a novel methodology, XYtracker, to estimate the surface projection of the fault extent and real-time seismic intensity. For large earthquakes, high-frequency ground motions tend to saturate over the magnitude range and strongly correlate with fault distance. As a result, this work can achieve the fault extent using seismic intensity and GMPE. We considered three types of fault models: point-source, line-source, and rectangle-source model. We found the most probable model parameters for each model by minimizing the residual sum of squares between the observed and estimated seismic intensities. The Akaike Information Criterion selected the most probable model among them. The strong motion data set of the 2008 Wenchuan, 2011 Tohoku, and 2016 Kumamoto earthquakes was used to test our methodology. The new method for estimating the fault geometry can obtain the ongoing rupture length and direction using the strong motion data. The model selection scheme with the Akaike Information Criterion selected the finite-source model to explain the shaking distribution. Results revealed that this new approach performed well in estimating the fault dimension. The method can promote the accuracy of the seismic intensity estimation for future large earthquakes, including the subduction earthquakes. Graphical Abstract
... Because there was insufficient data on the ground motion for the earthquake in Kuwait, it was necessary to use previously known attenuation relations to estimate the ground motion of the earthquake starting at its epicenter and reaching the particular location. [42] and [43] attenuation models were employed in this research. The former was used to model the ground motion of seismic sources in Kuwait, while the latter was used to simulate the ground motion of outlying areas of Kuwait for a model of the seismotectonic source. ...
Article
Full-text available
This study addresses the first and most important step in measuring the level of seismic hazard in Kuwait. As a result of development, there has been a rise in urban growth leading to the establishment of massive structures and skyscrapers in Kuwait. Therefore, there is demand for seismic risk assessment and the creation of a single seismic code for the country. Consequently, the historical and instrumental data were compiled into seismic catalogs of Kuwait and the active Zagros Seismic Belt. The magnitudes have been unified, extraneous earthquakes removed, and the catalogs' entirety has been taken into account. A seismotectonic model for the Kuwait region has been built to minimize the epistemic uncertainties. The model functions by combining seismicity patterns and structural geological conditions. The probability of experiencing the largest predicted earthquake emerging from every seismic source was calculated together with the parameters set for recurrence. Furthermore, the creation of hazard maps required a suitable ground motion attenuation relation within a logic tree design. Considering recurrence intervals of 100, 475, 975, and 2475 years (corresponding to 39.3 percent, 10%, 5%, and 2%, accordingly, the likelihood of exceedance in 50 years), a probability-based technique is utilized in the study to construct hazard maps at the following 0, 0.1, 0.2, 0.5, 1, 2, 3 and 4 seconds. The maps of scaling hazard areas were created using a 0.2 ° x 0.2 ° spacing grid throughout Kuwait. The five regions of Kuwait (Kuwait City, Salmiya Area, Sabriya Area, Managish Area, and Um Gudair Area) have all implemented a consistent spectrum of hazards. The findings of this study plus the vulnerability index serve the essential features required to calculate Kuwait's seismic risk.
... For Mexico, three types of models are used, depending on the fault type and the hypocenter's depth. The model of Abrahamson and Silva [14] is applied to shallow earthquakes, while the model of Zhao et al. [15] is applied to earthquakes of intermediate depth, and the model of Arroyo et al. [16] is related to interplate earthquakes according to the subduction fault. These models can be modified according to data on recent earthquakes. ...
Article
Full-text available
The design of earthquake-resistant structures by applying traditional or performance-based seismic analysis methods involves two large variables: the seismic risk of the area and the physical characteristics of the structure. Before analyzing any building, it is required to determine the seismicity in the location to evaluate the accelerations that the structure must withstand by deterministic or probabilistic methods. The typical results of a seismic study are the uniform hazard spectra in the rock layer related to a specific return period and structural damping. The building codes use different methods to obtain the elastic response spectra, seeking to offer simple procedures by using parametric factors to consider the soil type; however, the procedure tends to return conservative estimates. On the other hand, site-specific spectra offer accurate and less conservative acceleration values, with the disadvantage of an extensive and costly mathematical process, justifying their application mostly to important structures. This review article gives the state of the art of seismic elastic response spectra using probabilistic seismic hazard maps as inputs, taking into account the importance of the structure and the soil type, according to Mexican, U.S., and international building codes.
... The functional form was selected to be consistent with that used by Abrahamson and Silva [16] for the horizontal component in NGA model. [15] differ from the previous studies [12,17,18] in the fact that it accounts for the differences in the nonlinear site-response effects on horizontal and vertical components. Bommer et al. [19] reported the GMPM for V/H spectral ratio using a database including 1267 strong motion accelerograms from 392 events triggered in Europe and the Middle East with Mw ≥ 4.5 and R JB ≤ 100 km. ...
Article
Construction of vertical spectra (V) for scenario- and intensity-based seismic performance assessment is proposed based on scaling of the associated horizontal spectral ordinates (H) through respective V/H spectral ratios. Geometric mean of the spectra along and normal to the principal plane components is considered as the intensity measure of the horizontal component. V/H spectral shape is constructed using a large database (PEER-NGA-WEST2) of strong motion records contingent on the magnitude of the event, epicentral distance and average shear wave velocity. The procedure is based on the ratio of median vertical-to median horizontal-spectral ordinates which are shown to be well representative of the median of V/H spectral ratio. The construction is based on median response of the scenario and also applies to the design level (of a particular facility located in a specific site, which is also governed by a scenario) under certain assumptions and involves two steps: construction of normalized V/H spectra with unity at zero period scaled by the ratio of median vertical-to median horizontal- PGA (beta). The normalized V/H spectrum is shown to be characterized by three control points. An empirical estimate is proposed for beta as a function of epicentral distance. Normalized V/H spectra are further idealized for use with the intensity-based assessment per seismic codes. Vertical spectra using the proposed framework are compared with the various recommendations reported in the prior art including seismic codes and recorded events. PESMOS and COSMOS databases of strong motion events recorded in the Indian subcontinent are also used during the assessment.
... The minimum SNR applied at any FAS used in the inversion of this study is 5, to make the signal as free from background noise as far as possible. The f hc and f lc of the illustrated records in Figure 3a are 0.5 Hz and 25 Hz, and the spectra are usable at a frequency range from 1.25f hc to f lc /1.25 [48], as shown in the shaded area. It should be noted that if the number of frequency points of a record whose SNR ≥ 5 is less than 90% of the total number of frequency points (i.e., the SNR passing rate of the record is less than 90%), the whole record will be considered to be of poor quality and will not be used in the inversion. ...
Article
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In order to study the seismic wave attenuation characteristics of complex plate tectonics in and around the Kanto Basin, based on the focal mechanism and Slab1.0 model, the research area is divided into four regions. The one-step non-parametric generalized inversion technique was used to analyze the seismic wave attenuation characteristics of each region separately. The results show that the seismic path attenuation of earthquakes occurring in the shallow crust (Reg.1) is weak, and the seismic wave refraction at the crust–mantle boundary leads to almost no attenuation over a long hypocentral distance (>60 km), the frequency–dependent inelastic attenuation is also weak with the 0.5–20 Hz quality factor Q = 92.33f1.87. The seismic path attenuation of the upper mantle earthquakes occurring in the Kanto Basin (Reg.2) is strong, and the attenuation curve decreases with the increase of hypocentral distance, which is approximately parallel to the geometric diffusion R−2.0, the frequency–dependent inelastic attenuation is stronger with the quality factor Q = 27.75f1.08. The seismic path attenuation of subduction zone earthquakes (Reg.3 and Reg.4) is more obvious in the high–frequency band and has a frequency correlation, indicating that the attenuation of subduction zone earthquakes includes more inelastic attenuation. The frequency–dependent inelastic attenuation Q of Reg.3 and Reg.4 are 52.58f0.95 and 58.07f0.89, respectively.
... Because there was insufficient data on the ground motion for the earthquake in Kuwait, it was necessary to use previously known attenuation relations to estimate the ground motion of the earthquake starting at its epicenter and reaching the particular location. [42] and [43] attenuation models were employed in this research. The former was used to model the ground motion of seismic sources in Kuwait, while the latter was used to simulate the ground motion of outlying areas of Kuwait for a model of the seismotectonic source. ...
Article
Full-text available
This study addresses the first and most important step in measuring the level of seismic hazard in Kuwait. As a result of development, there has been a rise in urban growth leading to the establishment of massive structures and skyscrapers in Kuwait. Therefore, there is demand for seismic risk assessment and the creation of a single seismic code for the country. Consequently, the historical and instrumental data were compiled into seismic catalogs of Kuwait and the active Zagros Seismic Belt. The magnitudes have been unified, extraneous earthquakes removed, and the catalogs' entirety has been taken into account. A seismotectonic model for the Kuwait region has been built to minimize the epistemic uncertainties. The model functions by combining seismicity patterns and structural geological conditions. The probability of experiencing the largest predicted earthquake emerging from every seismic source was calculated together with the parameters set for recurrence. Furthermore, the creation of hazard maps required a suitable ground motion attenuation relation within a logic tree design. Considering recurrence intervals of 100, 475, 975, and 2475 years (corresponding to 39.3 percent, 10%, 5%, and 2%, accordingly, the likelihood of exceedance in 50 years), a probability-based technique is utilized in the study to construct hazard maps at the following 0, 0.1, 0.2, 0.5, 1, 2, 3 and 4 seconds. The maps of scaling hazard areas were created using a 0.2 ° x 0.2 ° spacing grid throughout Kuwait. The five regions of Kuwait (Kuwait City, Salmiya Area, Sabriya Area, Managish Area, and Um Gudair Area) have all implemented a consistent spectrum of hazards. The findings of this study plus the vulnerability index serve the essential features required to calculate Kuwait's seismic risk.
... The effect of these updated relationships on the V/H ratios was examined by computing the median response for earthquakes of approximately magnitude 6, at distances of 10, 20, and 30 km, appropriate to the dominant hazard identified in the 1996 probabilistic model. The average of the V/H ratios computed using the Silva (1995, 1997) and Campbell (1994) relationships were then compared to the average values that result from use of Abrahamson and Silva (1997) and Campbell and Bozorgnia (2003). ...
Technical Report
Full-text available
Site-Specific Seismic Site Response Model for the Waste Treatment Plant, Hanford, Washington
... A large number of worldwide GMPEs have been developed in the past two decades that can be paired with compatible horizontal GMPEs to estimate the V/H ratio. Examples of vertical GMPEs are studies by Abrahamson and Silva (1997), Campbell (1997), Sadigh et al. (1997), Bozorgnia and Campbell (2004), Ambraseys et al. (2005), Chiou and Youngs (2013), Bozorgnia and Campbell (2016a), Stewart et al. (2016), and Gu¨lerce et al. (2017). The second approach is to develop a GMPE directly for the V/H ratios obtained from the empirical data. ...
Article
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We develop a ground motion prediction equation (GMPE) for estimating the vertical ground motion amplitudes for crustal earthquakes in Taiwan. The data set used for the development includes strong-motion recordings mainly from Taiwan earthquakes (M3.5–7.6) and supplemented with large-magnitude earthquakes (M6.5–7.9) from other regions in the Pacific Earthquake Engineering Research Center (PEER) next generation attenuation (NGA)-West2 database. The functional form of the GMPE is similar to that of Phung et al. developed for the horizontal component (P20). The GMPE provides median and standard deviations of peak ground acceleration (PGA) and 5% damped pseudo spectral acceleration response ordinates of the orientation-independent average horizontal component of ground motion (RotD50) for the spectral period of 0.01–10 s. The vertical ground motion developed in this study can be paired with the P20 horizontal component model to estimate a vertical-to-horizontal (V/H) ratio that is unbiased. In the vertical component, we observe significant nonlinear site effects in the period of about 0.2–0.5 s, moderate nonlinear site effects in the period of about 0.01–0.04 s, and small nonlinear site effects in the period of about 0.05–0.075 s. Compared to our horizontal GMPE, anelastic attenuation is faster, V S30 -scaling is reduced, and nonlinear site response is weaker for the vertical component.
... Prior to the NGA west-1 project (Power et al., 2008) the ground motion prediction equations were based on the geometric mean spectral values of the two as recorded ground motions across all oscillator periods. Five GMPEs by Abrahamson and Silva 1997, Boore et al. 1997, Campbell 1997, Campbell and Bozorgnia 2003, Sadigh et al. 1993, 1997and Idriss 1991 were widely in use prior to 2008. ...
Thesis
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The definition of hazard-consistent ground motions for seismic design has been an active area of research in the past few decades. With the advancements in computing power we have taken giant steps in performance based seismic design (PBSD). At the heart of PBSD is performing non-linear response history analysis to verify the performance of a structural design. Among the challenges faced by engineers conducting response history analysis is the selection/generation of a set of ground motions that are compatible with a target spectrum that is representative of the seismic demand of the structure of interest. There are several ways to obtain spectrum compatible records. One can do scaling of the ground motions to closely match the response spectrum of an individual record to the design target spectrum. Another method is based on time or frequency domain modifications of the recorded acceleration time series to make them spectrum compatible. The focus of this study is to use spectral matching techniques to represent bi-directional demands accurately. The code spectrum represents bi-directional demand, which is quantified by either geo-mean spectrum (ASCE 7-05) or the maximum direction spectrum (ASCE 7-10). For 3-D analysis, the structure must be subjected to a pair of ground motions accounting for the bi-directional demand of the code spectrum. Although the present code provisions indicate that the RotD100 (Maximum direction) spectra of the individually matched motions be at least 110% of the design spectra, the values are well over 110% according to the analysis presented herein. The primary objective of this study is to propose a spectral matching method that captures the bi-directional demand of the structure and is compatible with design code requirements, named the “Match and Scale” approach. 398 pairs of ground motion records are considered to compute the mean and standard deviation of the scaling factors across oscillator periods. The proposed scaling factors represent the mean of the ratio of RotD100 spectral value of the individually matched motions to the spectral ordinates of the design target spectrum across all periods. Furthermore, another method to simultaneously match pairs of ground motions RSPmatchBi by Grant (2011), is explored for comparison purposes. The accuracy of the proposed method is assessed by performing non-linear time history analysis for bi-directional input and evaluating the variation in structural response as a result of considering different orientations of the input ground motion. The median structural response results from the proposed method is compared with the median response obtained with RSPmatchBi. The median responses fall in the same range, thus validating the proposed method.
... After that, the lowest frequency is selected where a flat response is observed (or the frequency specified by the user taking into account the research tasks). To avoid data loss, we divide this frequency by 1.25 [5]. The resulting frequency is the corner frequency of the high-pass pre-filtering. ...
Article
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This study is devoted to the development of algorithms and software for earthquake record processing. The algorithms are based on the methodology used by the Pacific Earthquake Engineering Research Center for the implementation of the scientific project NGA-West2. The purpose of processing is to determine reliable values of ground acceleration and other parameters of earthquakes from the available records of velocity time series. To analyze the operation of the algorithms, earthquake records (simultaneously recorded time series of acceleration and velocity) taken from the European Rapid Raw Strong-Motion database were used. The developed algorithms and the implemented software will allow in the future to form a database of strong motions for building regional attenuation models on the territory of the Russian Federation.
... A highfrequency 5-pole Butterworth acausal filter is used to remove the instrument response [4]. The corner frequency is determined from the frequency response of the instrument (the lowest frequency of the flat response boundary), which is reduced by a factor of 1.25 [5]. The need to reduce the corner frequency is due to the possible loss of data. ...
Conference Paper
The work is devoted to the adaptation of the earthquake record processing algorithm of the Pacific Earthquake Engineering Research Center to the peculiarities of seismic monitoring of the Baikal region. A tool for forming a database for building a regional seismic attenuation model is presented.
... Probabilistic seismic hazard analyses are usually performed with quasi-experimental ground motion models from global databases, where the average source, path, and site effects are valid for a particular area of interest. The site-specific site response differs from the global average based on the seismic velocity and basin depth field parameters used in ground motion models [77]. The comparison of the horizontal and vertical elastic design spectra obtained are shown in Figures 5 and 6, respectively. ...
Article
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Seismic hazard analysis of the earthquake-prone Eastern Anatolian Region (Turkey) has become more important due to its growing strategic importance as a global energy corridor. Most of the cities in that region have experienced the loss of life and property due to significant earthquakes. Thus, in this study, we attempted to estimate the seismic hazard in that region. Seismic moment variations were obtained using different types of earthquake magnitudes such as Mw, Ms, and Mb. The earthquake parameters were also determined for all provincial centers using the earthquake ground motion levels with some probabilities of exceedance. The spectral acceleration coefficients were compared based on the current and previous seismic design codes of the country. Additionally , structural analyses were performed using different earthquake ground motion levels for the Bingöl province, which has the highest peak ground acceleration values for a sample reinforced concrete building. The highest seismic moment variations were found between the Van and Hakkari provinces. The findings also showed that the peak ground acceleration values varied between 0.2-0.7 g for earthquakes, with a repetition period of 475 years. A comparison of the probabilistic seismic hazard curves of the Bingöl province with the well-known attenuation relationships showed that the current seismic design code indicates a higher earthquake risk than most of the others.
Article
A seismic sequence has struck the Yangbi county, west part of Yunnan Province in southwest China since May 18, 2021 . This region experienced the strongest ground shakings on the night of 21 May with the successive occurrence of four earthquakes with MS ≥5.0 in a short time and more small earthquakes. Large numbers of strong-motion recordings obtained in the four earthquakes with MS ≥5.0 (i.e. the MS 5.6 foreshock, the MS 6.4 mainshock, the MS 5.0 and MS 5.2 aftershocks) were analyzed in detail to characterize the source effects, distance decay, etc. The velocity pulse-like waveform at near-source station 53YBX and the significant asymmetry of distance decay along the SSE-NNW direction (i.e. much slower toward the SSE) in the MS 6.4 mainshock seem to hint the occurrence of the asymmetrical source rupture. The source rupture directivity for the four events were investigated by fitting the azimuth-dependent residuals of the PGAs. The MS 6.4 mainshock is characterized by the significantly asymmetrical bilateral rupture propagation, predominantly in the SSE direction with a rupture velocity of about 2.24 km/s. The PGA and PSAs from the four earthquakes were further compared with the predicted medians of the ASK14 and CY14 prediction models for global shallow crustal earthquakes. The negative inter-events residuals reflect the weaker source contributions of the Yangbi events to ground motions. The source contributions to short-period ground motions approximately show the dependence on earthquake type, that is, MS 5.6 foreshock > MS 6.4 mainshock > MS 5.2 aftershock, consistent with the dependence of stress drop on earthquake type. We further noted that the inter-events values for the MS 5.0 aftershock are far below those for the MS 5.2 aftershock. This may be attributed to the differences in the spatial and temporal distance to the mainshock, that is, weak source contributions from the close aftershocks to the mainshock. The values of adjustment coefficient Δc3 are almost positive, indicating the weaker anelastic attenuations in the study region. Finally, we also found that the distance scaling of significant duration can be well described by both empirical models (AS16 model for predicting significant duration and the BT14 model for empirically illustrating the ground-motion path duration).
Conference Paper
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В рамках реализации национальной программы развития науки и технологии, выдвинутой правительством Монголии, важнейшее значение имеет устойчивое осуществление национальных программ по изменению климата, по сокращению опустынивания и сохранению растений. В связи с этим мы проводим многосторонние исследования для достижения приоритетной цели «Повышение разнообразия и ресурсов растительного покрова Монголии» и выделению основных тенденций и состояния растительного разнообразия Монголии и его сохранения. Сегодня в стране известно 7617 видовых разнообразий растений и грибов. Около 60 % из них или 4576 видов, относятся к низшим криптогамным растениям, сюда входят 580 видов мха, 2287 видов водорослей, 630 видов грибов и 1079 видов лишайников (Conservation status of algae, fungi, lichens and mosses in Mongolia, 2022). А число видов высших сосудистых растений составляет 3041из 653 родов, 111 семейств [2]. В соответствии с категориями и критериями Красного списка (IUCN 2001; 2003) всемирного союза охраны природы (WWF) были установлены категории охранного статуса 876 видов (28.8 %) флоры Монголии. Из табл. 1 видно, что в результате исследования установлено 313 (35,7 %) видов «очень редких», 322 вида (36,8 %) «редких» растений. Это означает, что 72,5 % из видов флоры Монголии нуждаются в защитных мерах по сохранению
Article
Considering 869 ground-motion recordings from moderate-to-strong earthquakes that occurred in 2007–2019, this work investigates the variation of site amplification factors and develops an empirical site amplification model of the north–south seismic belt of China. The work first regresses a simple empirical ground-motion model (GMM) for the averaged reference site (the average shear-wave velocity for the top 30 m of the Earth (VS30) is about 760 m/s) by 322 recordings of the dataset. The regressed reference site model indicates that the slow distance attenuation still exists in earthquakes of the north–south seismic belt. Then, using the derived reference site model and 869 recordings, empirical site factors are computed and an empirical site amplification model is regressed. For the earthquakes in the north–south seismic belt, the proposed site amplification model predicts the site amplification for the 50th percentile rotated pseudospectral acceleration (RotD50 SA) with a damping ratio of 5% and periods 0.01–10 s. Moreover, the difference in site amplification factors between the north–south seismic belt of China and those of the Next Generation Attenuation (NGA) database is investigated. In general, variations of site amplification factors of the north–south seismic belt of China with VS30 are less significant than those from the NGA database. Therefore, the regional differences of ground motions caused by site effects are significant for the north–south seismic belt of China. For short periods (<1.0 s) and large values of VS30 (>300 m/s), the median site amplification of the north–south seismic belt is fitted well with most model predictions and the NGA data. The residual regional differences in the north–south seismic belt of China after site corrections can be applied to develop the more efficient global GMMs.
Conference Paper
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Article
A set of region-specific ground-motion models (GMMs) for subduction zone earthquakes are developed based on the database compiled by the Pacific Earthquake Engineering Research Center (PEER) Next Generation Attenuation: Subduction project (NGA-SUB). The subset used to develop the GMMs includes 3914 recordings from 113 subduction interface earthquakes with magnitudes between 5 and 9.2 and 4850 recordings from 89 intraslab events with magnitudes between 5 and 7.8. The functional form of the global GMM accommodates the differences in the magnitude, distance, and depth scaling for interface and intraslab earthquakes. In addition to the global model, region-specific GMMs are developed for seven regions: Alaska, Cascadia, Central America, Japan, New Zealand, South America, and Taiwan. The magnitude scaling and the geometrical spreading parameters of the global model are used in all region-specific models, with the exception of the Taiwan region, which has a region-specific geometrical-spreading term. Four region-specific terms are included in the median GMM: the large distance (linear R) scaling, linear site amplification scaling (ln(V S30 )), basin depth scaling (for Cascadia and Japan), and the constant term. The aleatory variability is also regionalized with larger aleatory variability at short periods for the Central America, Japan, and South America regions. Estimates of the epistemic uncertainty for the median and aleatory terms for each region are provided. The proposed global and region-specific GMMs are considered to be applicable to sites in the forearc region at distances up to 500 km, magnitudes of 5.0–9.5, and spectral periods from 0 to 10 s. The Cascadia-specific model is applicable to distances of 800 km including the backarc region.
Preprint
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This study presents an updated attenuation model to predict the peak ground acceleration ( PGA ), peak ground velocity ( PGV ), 5% damped pseudo-spectral acceleration ( SA ), and the average spectral acceleration ( AvgSA ) at the hill zone of Mexico City for interface earthquakes. The strong-motion dataset comprises 33 earthquakes recorded at CU station, covering a moment magnitude ( M w ) range from 6.0 to 8.1 and a source-to-site distance ( R rup ) range from 240 to 490 km. Given the small number of available observations, a Bayesian regression scheme is used to obtain the coefficients of the ground-motion prediction model (GMPM). In addition, the epistemic uncertainty in the estimation of the regression coefficients is evaluated, showing its impact on the framework of a probabilistic seismic hazard analysis (PSHA). The results are compared with models previously developed for the CU station, discussing the differences observed between the median predictions and their standard deviations. Likewise, seismic hazard curves are computed and compared with empirical curves obtained by counting the number of times per year that a given value of ground-motion intensity is exceeded. The results show that the dispersion of the GMPM proposed is lower than the previous models for PGA and SA , which means better predictability and more reliable estimates of the seismic hazard at the site.
Chapter
This chapter introduces seismic monitoring of structural systems for buildings and begins with a historical background of this topic in the United States. After providing the historical context, the chapter reviews common seismic instrumentation issues such as utilization of data, code versus extensive instrumentation, free-field instrumentation, record synchronization requirements and more. Recent developments in damage detection is examined including damage detection based on changes in natural frequencies, permanent deformations, and interstory drift. Finally, applications in Europe, the Middle East, and Japan of seismic monitoring of structural systems for buildings are discussed.
Article
Stiffness retrofit is a very effective technique to increase the seismic capacity of low-rise buildings. However, the shift of the fundamental period might lead to potential adverse effects when considering the spectral content of the ground motions. To address this issue, this paper proposed a fundamental-period-preserving (FPP) retrofit methodology. By augmenting traditional stiffness retrofit techniques with inerters, the fundamental period can be preserved. In addition, the normalized seismic input force and higher mode effects can be reduced. Different retrofit examples were evaluated through a series of nonlinear static and nonlinear dynamic analyses. Different performance objectives, including roof drift, story drift, story acceleration, base shear, and the force generated by inerters were used to demonstrate the effectiveness and the applicability of FPP approach in structure retrofit. The results showed that the FPP approach is an attractive alternative to the seismic retrofit of low-rise buildings.
Article
Earthquakes have occurred frequently in western China (Sichuan, Tibet, etc.) while the complex site conditions in western regions bring great uncertainty to the seismic performance of isolated high-speed railroad bridges (HSRBs). By studying the relationship between structure-dependent and structure-independent seismic intensity measures, soil site conditions are taken into account in the probabilistic seismic demand model (PSDM), which is applied to analyze the failure probability of the isolated HSRB under different site conditions. Based on the design parameters and test results of a typical isolated HSRB in western region, the analysis of the finite element model of the structure was performed. Probabilistic seismic demand models of the isolated HSRB were developed. The seismic fragility curves of the isolated HSRBs were obtained and the failure probabilities under different site conditions were compared and analyzed. The evaluation of the failure probability that the failure probability of the isolated HSRBs in the site area with seismic intensity of 9 is 35.84% and 78.19% under the soil site categories D and E, respectively. Therefore, the seismic spectrum characteristics of the soil site are an important factor affecting the seismic response of isolated HSRB structures. This study provides a more effective modified PSDM for seismic performance assessment of isolated HSRBs under the different site conditions.
Article
Structural systems have deteriorated seismic performance as they are exposed to thermal effect due to dependency of material properties to temperature. Following an earthquake, once structure has already some residual displacement, fire ignition is very likely to occur. This makes it necessary to evaluate structural response of a building considering the fire event which follows an earthquake to have robust evaluation of structural response. Thus, it is required to model structural systems with consideration of both earthquake and thermal loads to capture multi-hazard behavior. In this study, performance of two-dimensional steel frames in case of fire following an earthquake is evaluated and collapse parameters of frames are calculated. Fragility curves related to collapse and residual story drift demands are given, and comparison of results between earthquake and fire-following-earthquake is illustrated. In addition, collapse probability of frames in fifty years is also given. Results of collapse performance evaluation are adjusted with the consideration of expected seismic hazard on site. Median collapse capacity decreases more than 30% and there is an apparent increase in collapse probability of fire-exposed frames in fifty years, which is more than three times for some frames.
Article
We develop empirical estimates of site response at seismic stations in the Los Angeles area using recorded ground motions from 414 M 3–7.3 earthquakes in southern California. The data are from a combination of the Next Generation Attenuation-West2 project, the 2019 Ridgecrest earthquakes, and about 10,000 newly processed records. We estimate site response using an iterative mixed-effects residuals partitioning approach, accounting for azimuthal variations in anelastic attenuation and potential bias due to spatial clusters of colocated earthquakes. This process yields site response for peak ground acceleration, peak ground velocity, and pseudospectral acceleration relative to a 760 m/s shear-wave velocity (VS) reference condition. We employ regression kriging to generate a spatially continuous site response model, using the linear site and basin terms from Boore et al. (2014) as the background model, which depend on VS30 and depth to the 1 km/s VS isosurface. This is different from past approaches to nonergodic models, in which spatially varying coefficients are regressed. We validate the model using stations in the Community Seismic Network (CSN) that are in the middle of our model spatial domain but were not considered in model development, finding strong agreement between the interpolated model and CSN data for long periods. Our model could be implemented in regional seismic hazard analyses, which would lead to improvements especially at long return periods. Our site response model also has potential to improve both ground-motion accuracy and warning times for the U.S. Geological Survey ShakeAlert earthquake early warning (EEW) system. For a point-source EEW simulation of the 1994 M 6.7 Northridge earthquake, our model produces ground motions more consistent with the ground-truth ShakeMap and would alert areas with high population density such as downtown Los Angeles at lower estimated magnitudes (i.e., sooner) than an ergodic model for a modified Mercalli intensity 4.5 alerting threshold.
Article
This study aims to quantify seismic hazard assessments in the Jazan region. For this purpose, we determined earthquake recurrence parameters for potential seismic zones that may export risk to the region. A total number of ten seismic zones were identified based on the morphotectonic nature, seismic energy pattern, and previous studies. Estimates of the b-value varied from 0.74-1.42, reflecting different processes of tectonic activities. The maximum possible magnitudes (Mmax) of 5.9±0.3 to 8.3±1.1 are anticipated to be occurred in the region between 48 and 2090 years with annual probabilities of 13%, 23%, and 36% in 25, 50, and 100 years of life, respectively. Finally, the maximum expected magnitudes obtained from this study were used in cooperation with five alternative attenuation relationships to predict peak ground accelerations. The seismic hazard map of 84% was produced at hard rock using logic tree uncertainties, showing a high seismic hazard alongside the coastline shores while a low seismic hazard extended inside the Arabian Shield that is assumed to have a stable continental crust. The response spectra at hard rock in Jizan city showed maximum PGA values corresponding to spectral frequencies of 2 to 5 Hz, implying that high-frequency vibrations may have an impact on building structures.
Article
In the performance-based earthquake engineering framework, the ground motion intensity measure (IM) plays both the role of predicting structural seismic response and calculating seismic hazard curves. This study investigates the optimal ground motion IM for high-speed railway girder bridges (HRGBs). To that end, three representative HRGBs are selected for performing modal analysis first and results show that the vibration modes of HRGBs are scattered, and the contribution of high-order modes cannot be ignored. Then, a new intensity measure, S*, calculated by taking the spectral acceleration as the base and the mass participation coefficient as the index, is proposed. Through probabilistic seismic demand analysis (PSDA), compared with other 17 IMs, S* is more feasible, efficient and sufficient. Moreover, the attenuation relationship in terms of S* is proposed by simply modifying the existing attenuation models. Thus, S* is considered as the optimal IM for HRGBs.
Article
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This study has made the site response and liquefaction analysis of a solar power plant site in the northern part of Bangladesh. The site is situated in an area that is near to Himalayan thrust and home to numerous large earthquakes including the 1885 Bengal, the 1897 Great Indian, the 1930 Dhubri, the 1934 Bihar–Nepal, the 2011 Sikkim, and many other relatively smaller earthquakes. Because of the past seismicity and significance of the power plant site, seismic investigation has been performed in the seismic control region within a radius of 300 km from the center of the plant site. The peak ground acceleration (PGA) value at the bedrock level for a return period of 475 years for the site has been estimated to be 0.23 g. For the last few decades, the site coefficients are generally estimated from the mean shear wave velocity for the top 30 m of a location. The surface PGA of a location is equal to the product of the bedrock PGA and the estimated site coefficient. If the bedrock is located at a depth greater than 30 m below the ground, the site effect estimated from Vs30 cannot appropriately represent the site coefficient. For the study site, the bedrock is approximately 150 m below the ground. For loose sedimentary deposits of this site, the site coefficient based on Vs30 to assess the PGA on the surface is not suitable. In this research, site amplification factor based on Vs30, equivalent-linear, and nonlinear methods has been carried out to estimate the PGA at the surface of the site. In this site, the susceptibility of liquefaction has been estimated by utilizing 66 boreholes having SPT-N values at every 1.5 m distance from the surface to a depth of 20 m. Here liquefaction susceptibility has been assessed by applying Seed and Idriss’ simplified method, the Japanese method, and the Chinese method. The estimated LPI contours show that the soil up to a depth of 20 m for almost all the boreholes is highly susceptible to liquefaction.
Article
In this paper we summarize our recently-published work on estimating horizontal response spectra and peak acceleration for shallow earthquakes in western North America. Although none of the sets of coefficients given here for the equations are new, for the convenience of the reader and in keeping with the style of this special issue, we provide tables for estimating random horizontal-component peak acceleration and 5 percent damped pseudo-acceleration response spectra in terms of the natural, rather than common, logarithm of the ground-motion parameter. The equations give ground motion in terms of moment magnitude, distance, and site conditions for strike-slip, reverse-slip, or unspecified faulting mechanisms. Site conditions are represented by the shear velocity averaged over the upper 30 m, and recommended values of average shear velocity are given for typical rock and soil sites and for site categories used in the National Earthquake Hazards Reduction Program's recommended seismic code provisions. In addition, we stipulate more restrictive ranges of magnitude and distance for the use of our equations than in our previous publications. Finally, we provide tables of input parameters that include a few corrections to site classifications and earthquake magnitude (the corrections made a small enough difference in the ground-motion predictions that we chose not to change the coefficients of the prediction equations).
Empirical prediction of near-source ground motion from large earthquakes
  • K W Campbell
Campbell, K. W. (1993). Empirical prediction of near-source ground motion from large earthquakes, Proc. International Workshop on Earthquake Hazard and Large Dams in the Himalaya, January 15-16, 1993, New Delhi, India.
Soil amplification and vertical to horizontal ratios for analysis of strong motion data from active tectonic regions, Appendix 2C in Guidelines for Determing Design Basis Ground Motions, Vol2: appendices for ground motion estimation
  • R Youngs
  • Il
Youngs, R. IL (1993). Soil amplification and vertical to horizontal ratios for analysis of strong motion data from active tectonic regions, Appendix 2C in Guidelines for Determing Design Basis Ground Motions, Vol2: appendices for ground motion estimation, TR-102293.