Majid Mahood

International Institute of Earthquake Engineering and Seismology | iiees · Seismology

The main purpose of this study is to investigate the temporal changes in the attenuation of coda waves before and after the 7.3 magnitude Kumamoto earthquake in the Kumamoto region of Japan. In this study, the single back scattering method has been used to estimate the attenuation of coda waves. The attenuation was estimated using 474 local earthqu...

This paper aims to evaluate the general code spectrum of the Iranian code of practice for seismic-resistant design of buildings. The general code spectrum at nine sites with different site classes within the mega city of Tehran is compared with those of ASCE 7–16 and a site-specific design spectrum. It is shown that though the general code spectrum...

One of the largest earthquakes in the Zagros region occurred on November 12, 2017, in Sarpol-e Zahab whit Mw=7.3. We considered the aftershocks of this event and collected the S-wave amplitude spectra from 87 strong-motion recordings to determine the source, path and site effects using a non-parametric generalized inversion technique. The grid-sear...

A nonparametric generalized inversion technique has been used to derive source parameters, attenuation characteristics, and site amplification effects from S-wave spectra of the Mw 7.3 Sarpol-e Zahab, November 12, 2017 aftershocks recorded at 13 stations in the hypocentral distance of 9–70 km. We used a total number of 87 Fourier amplitude spectra...

The observed statistical seismic quantity is critical to understanding the nature of earthquakes and potential hazards in earthquake-prone areas. We have studied the nowcasting concept, which examines the current uncertain situation of earthquake risk assessment in Sarpol-e Zahab and the surrounding areas. In order to evaluate the statistical distr...

Estimation of Seismic Wave Attenuation in Fariman Region Document Type : Research Article Abstract: Attenuation of seismic waves is considered a very important characteristic of the wave propagation path because this physical parameter affects how the seismic waves propagate, and consequently knowing the amount of it is essential in accurate calcu...

Utilizing the aftershocks of the 21th, Aban, 1396 Ezgeleh-Sarpolzahab earthquake at 21:48 of local time (12th, November 2017 at 18:18 of global time), the single-back scattering method for coda waves are employed. In order to achieve this, 170 accelerograms of local earthquakes having magnitudes between 3.8 and 6 Mw recorded by the accelerogram net...

Bayesian probability theory is an appropriate and useful method to estimate parameters in seismic hazard analysis. The analysis in Bayesian approaches is based on a posterior belief, also their special ability is to take into account the uncertainty of parameters in probabilistic relations and a priori knowledge. In this study, we used the program...

In this study, the attenuation of coda waves has been estimated in the western part of Iran plateau using single backscattering method. Coda wave attenuation was estimated at seven central frequencies (fc = 1.5, 3, 4.5, 6, 9, 12, 18 Hz) and eight lapse times (tl= 10, 20, 30, 40, 50, 60, 70, 80s). More than 9100 local earthquakes with magnitude rang...

In this study, we used the program for seismic hazard Bayesian estimate elaborated by Alexey Lyubushin. However, earthquake hazard parameters of maximum magnitude (Mmax), β value, and seismic activity rate or intensity (λ) and their uncertainties for the 30 different source regions in Zagros seismotectonic province have been evaluated with the help...

High frequency quality factors Qc, Qp & Qs have significant roll to study the simulation of the strong ground motion, seismic hazard analysis and seismic zoning. The 2017 April 5 Mw 6 Do Qaleh Fariman earthquake occurred southeast of the megacity of Mashhad, the center of Khorasan –e Razavi province, at the southern boundary of Kopeh-Dagh. Immediat...

Two destructive earthquakes occurred on 11th of August 2012 (Mw 6.5 and 6.4) in the Ahar and Varzeghan regions, NW Iran. High-frequency strong-motion data of these earthquakes have been analyzed to determine the Qb(f) and source parameters by inversion of the recorded data. The data from a local network of 21 and 19 acceleration records for the fir...

Earthquake Early Warning System (EEWS) is issued by detection of P-wave, estimation of seismic parameters and decision to alarm. The EEWS provides advance warning of estimated seismic intensities and expected arrival time of S-waves. These estimates are based on prompt analysis of hypocenter location and earthquake magnitude using data observed by...

High-frequency strong-motion data of two recent major earthquakes in the Ahar-Varzaghan region, Northwestern Iran, have been analyzed to determine shear-wave quality factor (Q β (f)) and seismic source parameters. Data from a local array of 12 stations, two main shocks (Ahar-Varzaghan doublet earthquakes (M w 6.4 and 6.3) on August 11, 2012 and 38...

Earthquake magnitude and P wave amplitude (Pmax) are important parameters for Earthquake Early Warning Systems (EEWS), yet their dependence on source mechanism, focal depth and epicentral distance (∆) has not been fully studied. We examined a method to estimate an earthquake's magnitude and epicentral distance using the initial part of P-wave data...

The recent major plans for socio-economic-industrial development of Makran region necessitate a thorough investigation of the earthquake and tsunami risk assessment in the Makran region. Some major industrial development, such as, the oil and gas export terminals, petrochemical, steel factories, airports, industrial free zones, Navy base, and other...

Two recent earthquakes that struck the Azarbayjan region, NW-Iran, on 10 August 2012 (Mw=6.2 and 6.1) caused major concern about future earthquake occurrences in Azarbayjan Region. In order to improve the capability of NW-Iran earthquake early warning system for giving early warning of a damaging earthquake in the Azarbayjan Region, we explored an...

The frequency-dependent attenuation of the crust in Eastern-Iran is investigated by using 132 local earthquakes having focal depths in the range of 5–25 km. We estimated the quality factor of coda waves (Qc) and body waves (Qp and Qs) in the frequency band of 1.5–24 Hz by applying the single backscattering theory of S-coda envelopes and the extende...

On 11th of August 2012 the region was surprisingly struck by a shallow Mw 6.4 (USGS) earthquake with pure right-lateral strike-slip character only about 50 km north of the North-Tabriz Fault. An east-west striking surface rupture of about 20 km length was observed in the field by Geological Survey of Iran. Only 11 minutes later and about 6 km furth...

Predictive attenuation relationships have been developed for peak ground acceleration and spectral coordinates based on observed and simulated records for East Central Iran. First, the predictive relationships are derived based on observed records. The observed data set, which was considered, includes a total of 258 records from 109 earthquakes wit...

The separation of residual gravity anomaly from regional gravity has considerably been studied for many years in gravity explorations. In addition, it is considered as a critical step in gravity data inversion. Some techniques have been developed for regional–residual anomaly separation both in space and frequency domains. One of these techniques f...

Predictive attenuation relationships have been developed for peak ground acceleration and spectral coordinates based on observed and simulated records for East Central Iran. First, predictive relationships are derived based on observed records. The observed data set, which was considered, includes a total of 258 records from 109 earthquakes with a...

The attenuation properties of the lithosphere in the Bam region, East-Central Iran, have been investigated. For this purpose, 42 local earthquakes having focal depths less than 25km have been used. The quality factor of coda waves (Qc) has been estimated using the single back-scattering model. The quality factors Qp, Qd (P and direct S-waves) have...

We simultaneously estimated Qp−1 and Qs−1 by applying the extended coda-normalization method at 39 stations of three local networks in the East-Central Iran. We measured frequency-dependent attenuation of both P and S waves for the frequency range of 1.5, 3.0, 6.0, 12 and 24 Hz. We have analysed 266 three-component seismograms of 53 local earthquak...

The attenuation of coda waves, Q c , has been estimated in Zarand, Jiroft, and Bam regions of east central Iran using a single back-scattering model of S-coda envelopes. For this purpose, the recordings of 97 earthquakes by three seismic networks and a local strong ground motion network have been used. In this research, the frequency-dependent Q c...

In this paper, the strong motion accelerograms of October 17, 2009, Tehran-Ray earthquake (MW=4.0) of south of Tehran were analyzed. (i) Using derived SH-wave spectral data, at first the parameters Wo (long period spectral level), fc (corner frequency) and Q(f) (frequency dependent, average shear wave quality factor), appropriate for the best-fit B...

We analyze the strong motion accelerograms of the moderate (M w = 6.1), March 31, 2006, Darb-e-Astane earthquake of western Iran and also those of one of its prominently recorded, large (M w = 5.1) foreshock and (M w = 4.9) aftershock. (1) Using derived SH-wave spectral data, we first objectively estimate the parameters \(\mathit{\Omega} _{\rm o}\)...