Francisco Vidal

Francisco Vidal
University of Granada | UGR · Instituto Andaluz de Geofísica y Prevención de Desastres Sísmicos

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91
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Publications

Publications (91)
Article
Full-text available
This paper presents the results of a series of tests for geometric and mechanical characterization of concrete block (from 8 local factories) and cement mortar used in masonry in the region of Tuxtla Gutierrez. The laboratory tests were performed according to standards and protocols of Mexican organisms. The results of the analyzed samples show tha...
Conference Paper
Full-text available
Typological characterization and seismic vulnerability of 1942 buildings in the Historic Centre of Tuxtla Gutierrez, Chiapas, have been estimated with the criteria of the Eu-ropean Macroseismic Scale (EMS) and by the Seismic Vulnerability Index Method (VIM). The majority of analysed structures (91.81%) are masonry buildings, 7.93% are RC frames and...
Article
Full-text available
The town of Adra (Almeria Province, South-Eastern Spain) has been seriously affected by historical damaging earthquakes in 1487, 1522, two in 1804 and in 1910 with epicentres offshore in the Alboran Sea that reached onshore an estimated maximum intensity of VIII, IX, VIII, VIII–IX and VII–VIII, respectively. Additionally, in the instrumental period...
Conference Paper
Historical and recent Chilean earthquakes (1906, 1960, 1985, 2010) showed similar building damage distribution in Viña del Mar city related to ground conditions and building height A detailed analysis of 122 geotechnical reports has allowed us to obtain their geotechnical parameters and the V S surface ground structure (calculated from N SPT data)...
Conference Paper
Full-text available
The high seismic hazard level of the city of Tapachula (Chiapas, Mexico) and observed geological differences in the urban area requires a V S surface structure estimate in order to know the characteristics of local seismic response. In this work we have used empirical methods to characterize earthquake ground motion in different zones of the city....
Research
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En la serie sísmica de 2011, el 11 de mayo ocurrieron tres pequeños terremotos (Mw 4.6, 5.2 y 3.6, respectivamente), de poca profundidad (~4 km) y con epicentros muy cercanos a Lorca (< 5km). La estación LOR, situada en roca en el centro de la ciudad, registró una PGA de 0.27g, 0.36 g, y 0.06 g, respectivamente. La intensidad instrumental del terre...
Conference Paper
In Adra town during 1993 and 1994 small earthquakes took place with a magnitude of 5.0 (Mw). Despite these earthquakes were moderate, several buildings suffered damage. The local soil conditions influenced the characteristics of the earthquake-shaking scenarios. In fact, these scenarios played a key role about the type of buildings damages reported...
Article
Since early 1983, when the Andalusian Seismic Network began to operate, to late 1987, 4198 microearthquakes have been located in the Central Betics. This activity is quite nonuniform in space and time. The most important fault systems drawn by the geologic cartography and the observed lineaments by Landsat images are N20-40E N60-80E and N120-140E....
Article
This paper estimates fundamental translational period and damping ratio parameters and examines the changes in dynamic characteristics of a set of low-to-medium rise buildings in Lorca town (SE of Spain) affected by the May 11th, 2011 earthquake. These building parameters have been calculated analysing structural dynamic response from ambient vibra...
Article
Local site effect assessment based on subsurface ground conditions is often the key to evaluate urban seismic hazard. The site effect evaluation in Lorca town (south-eastern Spain) started with a classification of urban geology through the geological mapping at scale 1:10,000 and the use of geotechnical data and geophysical surveys. The 17 geologic...
Article
Exceptional ground motions have been observed in the near-source region in relatively small and moderate earthquakes such as the Lorca earthquake of 2011. In the Mw 5.2 mainshock, horizontal peak ground acceleration reached 0.37 g at the LOR accelerograph station in the north-central part of the town. Maximum ground acceleration and velocity in thi...
Article
Full-text available
We studied the surface properties of eruptive material from Deception Island (South Shetland Islands, Antarctica). The surface free energy and zeta potential were analyzed in obsidian and pumice stones immersed in different electrolytes (NaCl, BaCl2, AlCl3, VCl2, PbCl2, CdCl2, FeCl3, and CrCl3). The results show that obsidian has a monopolar charac...
Conference Paper
Full-text available
The characteristics of earthquake shaking are affected by the local site conditions. The effects of the local soil conditions are often quantified via an amplification factor (AF), which can be defined for any ground motion parameter, but most commonly are assessed for acceleration response spectral values at different periods or elementary by peak...
Article
Full-text available
When measuring vibration of a structure is performed is not always possible to obtain a full description of its dynamical response. That is, it can only measure this response at selected points of the whole structural system, since it is difficult to make these measurements in each and every one of the points that make up this system. It should be...
Conference Paper
Full-text available
Granada city (Southern Spain) is in an area of moderate seismicity, but suffered in the past damaging earthquakes. It presents the highest seismic hazard in Spain (0.24g for a 475 years return period). On 11 April 2010 a very deep (h=613 km) earthquake (M W =6.3) with epicentre close to Granada was recorded by several accelerographs and seismic sta...
Conference Paper
Full-text available
Two small earthquakes took place on May 11 th , 2011 (Mw 4.6 and 5.2, respectively), with a shallow depth (4.2 km), and whose epicenters were very close to the city of Lorca (< 5 km). The LOR station, located on rock in the city center, registered a PGA equal to 0.27 g and 0.36 g, respectively. The strong ground motion parameters (Arias Intensity,...
Conference Paper
Full-text available
RESUMEN El análisis de vulnerabilidad y de escenarios de daños sísmicos (EDS), incluyendo herramientas de evaluación basadas en SIG para los usuarios finales, se han desarrollado en programas internacionales (p.e. HAZUS ,1999; RISK-UE, 2004), para apoyar la planificación y priorización de programas de reducción de riesgo sísmico. El 11 de mayo de 2...
Conference Paper
In the last fifty years, the population of Granada and its metropolitan area has doubled. This has led to an increase in built-up land of approximately 4650 ha. This research study focuses on differential vertical displacement assessment in four towns (Albolote, Atarfe, Fuente Vaqueros, Churriana) and La Chana district of Granada city for an earthq...
Conference Paper
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Underlying the metropolitan area of Granada (southern Spain) exist thick Quaternary sediments with Holocene deposits extending more than 200 m. In addition, there is a substantial shallow groundwater reservoir where the water table is at a depth of only a few meters in its NW zone. This study assesses local liquefaction throughout the area. We have...
Conference Paper
Soil densification because of intense seismic movement causes settlements that are a threat to building constructions. The calculation of the maximum number of expected settlements due to seismic activity is important for the design of earthquake-resistant foundations. The maximum shear modulus (Gmax) or the maximum dynamic shear stiffness modulus...
Conference Paper
Full-text available
El cálculo de la susceptibilidad a licuefacción, para suelos arenosos y suelos finos (arcillosos y/o limosos), se ha realizado siguiendo un método basado en Seed et al. (2003) y Bray & Sancio (2006), para un evento sísmico similar al acaecido en 1431 en Granada. Se ha usado una gran base de datos con la que se han analizado y cartografiado aspectos...
Chapter
Full-text available
RESUMEN En la serie sísmica de 2011, el 11 de mayo ocurrieron tres pequeños terremotos (Mw 4.6, 5.2 y 3.6, respectivamente), de poca profundidad (~4 km) y con epicentros muy cercanos a Lorca (< 5km). La estación LOR, situada en roca en el centro de la ciudad, registró una PGA de 0.27g, 0.36 g, y 0.06 g, respectivamente. La intensidad instrumental d...
Article
Full-text available
Since 2008 it has been testing at the Autonomous University of Chiapas the clay brick used in buildings of the city of Tuxtla Gutierrez, Chiapas, Mexico. The study includes the identification of variations on geometry properties, weight, absorption and strength of bricks. Besides the individual properties of brick units, piles of bricks were tested...
Conference Paper
Full-text available
RESUMEN El sismo profundo del 11-4-2010, con epicentro próximo a la ciudad de Granada, se registró en seis acelerógrafos en el área urbana (en la que predominan los rellenos) y en la cercana estación en roca SELV. Por la incidencia normal del frente de ondas y la proximidad del epicentro, las distancias hipocentrales son prácticamente iguales en to...
Conference Paper
Full-text available
RESUMEN Los registros del movimiento sísmico fuerte permiten cuantificar una serie de parámetros ingenieriles instrumentales para estimar la severidad de la sacudida y usarlos como índices de potencial de daño. Se han analizado 149 acelerogramas de 80 terremotos del área Euro-mediterránea, con intensidades macrosísmicas EMS entre III y VIII. Se han...
Conference Paper
Full-text available
RESUMEN Para evaluar los efectos de sitio en la ciudad de Granada (sur de España), se han clasificado sus suelos a partir de la velocidad media de onda S en los primeros 30 m (V S 30) siguiendo los criterios de la NCSE-02. La estructura superficial del terreno se ha caracterizado a partir de la inversión de la curva de dispersión de ondas Rayleigh,...
Conference Paper
Full-text available
RESUMEN Para la estimación de dos Escenarios de Daños Sísmicos (EDS) en la ciudad de Granada se han seleccionado como terremotos de referencia los históricos de 1431 (I 0 ≥IX) y 1806 (I 0 =VIII) con epicentros cercanos a la ciudad. Para cada evento se han evaluado primero los escenarios del movimiento del suelo (en PGA e intensidad), aplicando fact...
Conference Paper
Full-text available
RESUMEN Se describe el proceso empleado para determinar la vulnerabilidad sísmica de una zona del centro histórico de Tapachula, Chiapas. El estudio se basa en un censo detallado de 219 edificaciones realizado por estudiantes de la Facultad de Ingeniería de la Universidad Autónoma de Chiapas en abril de 2008. La vulnerabilidad de las edificaciones...
Conference Paper
RESUMEN Se describe el proceso empleado para determinar la vulnerabilidad sísmica de una zona del centro histórico de Tapachula, Chiapas. El estudio se basa en un censo detallado de 219 edificaciones realizado por estudiantes de la Facultad de Ingeniería de la Universidad Autónoma de Chiapas en abril de 2008. La vulnerabilidad de las edificaciones...
Article
Full-text available
A probabilistic seismic hazard assessment of Andalusia (Southern Spain) in terms of peak ground acceleration, PGA, and spectral accelerations, SA(T), is presented in this paper. In contrast to most of the previous studies in the region, which were performed for PGA, making use of Intensity-to-PGA relationships, hazard was here calculated in terms o...
Conference Paper
Full-text available
In order to evaluate the surface ground motion characteristics at Granada town (southern Spain), a classification of the shallow urban geology based on geotechnical data and geophysical surveys has been carried out. Shear-wave velocity structures have been estimated in different soil conditions by means of inversion of Rayleigh wave dispersion data...
Article
During the year 2007 two seismic sequences occurred in the proximity of Moron de la Frontera town (Seville, SW of Spain), a region where several important local and regional earthquakes have historically occurred. The first sequence, with more than 150 earthquakes (m
Article
Objectives: To predict the potential number of victims which caused by a hypothetical scale VIII earthquake VIII with the epicentre in Sierra Elvira (near Granada) and to classify the casualties based on of the location and severity of the injuries. These data were compared with those estimated for an other much less probable earthquake of scale IX...
Article
On 29 January 2005, a MW 4.8, Imax VI–VII, earthquake occurred near the village of La Paca, SE Spain. The aftershock sequence shows distinct heterogeneity, manifested in a non-uniform temporal decay of activity and different source mechanisms for the main shock and the largest aftershocks. We analysed 262 earthquakes of the seismic series in order...
Article
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Objetivos: Estimar el número potencial de víctimas en un hipotético terremoto de intensidad de grado VIII (EMS), con epicentro en Sierra Elvira (cercano a Granada) y clasificar los heridos en función de la localización y gravedad de sus lesiones. Estos datos se comparan con los estimados para otro terremoto de intensidad IX, mucho menos probable, u...
Conference Paper
Full-text available
The global objective of the SISMOSAN Project has been to provide a general seismic risk assessment of Andalusian region (Southern Spain) associated with the ground motions expected for a return period of 475 years. The project was financed by Civil Defence of Andalusia and its results will be applied to the definition of regional emergency plans. W...
Article
The depth of the basement and the structure of shallow sedimentary materials in Mula town (SE Spain) have been estimated applying an association of the spatial autocorrelation (SPAC) method and the horizontal-to-vertical spectral ratio (HVSR) method for ambient noise. Regular pentagonal arrays with radii up to 30m have been employed for velocity co...
Article
The determination of seismic hazard oriented to seismic risk management in urban areas requires an investigation over the possibility of resonance in the dynamic behaviour of buildings and soils. This work classified, according to their seismic amplification capacity, urban shallow geologic materials in 5 types identifying the nature of the materia...
Article
SUMMARY At the end of the XIX century, F. Omori started to design horizontal pendulums. The J. & A. Bosch brothers, from Strasbourg, commercialised a version of this instrument known as Bosch-Omori. Due to its simplicity and affordable price it was widely distributed. Nine such instruments were operated at seismic observatories in Spain. As a part...
Article
Full-text available
El objetivo fundamental de este trabajo es el profundizar en el conocimiento de la estructura y dinámica de la región Ibero-Mogrebí mediante la obtención de imágenes tomográficas de su corteza y manto superior. Para ello hemos utilizado un nuevo método cuya innovación principal es la parametrización del modelo de velocidad basado en redes definidas...
Article
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Levy flights representation is proposed to describe earthquake characteristics like the distribution of waiting times and position of hypocenters in a seismic region. Over 7500 microearthquakes and earthquakes from 1985 to 1994 were analyzed to test that its spatial and temporal distributions are such that can be described by a Levy flight with ano...
Article
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Levy flights were introduced through the mathematical research of the algebra or random variables with infinite moments. Mandelbrot recognized that the Levy flight prescription had a deep connection to scale-invariant fractal random walk trajectories. The theory of Continuous Time Random Walks (CTRW) can be described in terms of Levy distribution f...
Article
Concentration of the polluting substances and character of their dispersion in the air depends on the properties of the atmospheric boundary layer as well as on the char- acteristics of the pollution sources (intensity of emissions, their spatial location). The transference of the substances in the air is dependent on various meteorological fac- to...
Article
Airborne remote sensing data provides data for a very high-resolution land use map with the roughness changes in each crop type estimated from plant parameteres through time in the Alpilles region in southern France. There are 18 surface temper- ature maps from an airborne scanner and a series of radiosoundings. Further are data of the sensible sur...
Article
Full-text available
Recent destructive earthquakes have shown that damage distribution is generally related to soil typology, large differences being noticed in the level of damage for relatively short distances. In order to evaluate the site effects in Adra town (southern Spain), geological and geomorphological survey and microtremor measurements were carried out. Th...
Article
- In Almería city large earthquakes occurred and many buildings were completely destroyed in these historical earthquakes. The actual population of Almería city is about 200,000 people. This population is rapidly increasing and new urbanizing areas are growing to the eastern part of the city where they are located in softer soil conditions. Consequ...
Article
A quantitative method to characterize the spatio-temporal evolution of the seismic activity of a region for a given time interval is proposed in this paper. The epicentral region is divided in equal area parallelograms that we call “cells”. A probability Pi is assign to every cell depending on its seismic activity level. The evolution of the mutual...
Article
We used over 1000 regional waveforms recorded by 60 seismic stations located in northwest Africa and Iberia to map the efficiency of L g and Sn wave propagation beneath the Gulf of Cadiz, Alboran Sea and bounding Betic, Rif and Atlas mountain belts. Crustal attenuation is inferred from the tomographic inversion of L g/Pg amplitude ratios. Upper man...
Article
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A number of different geodynamic models have been proposed to explain the extension that occurred during the Miocene in the Alboran Sea region of the western Mediterranean despite the continued convergence and shortening of northern Africa and southern Iberia. In an effort to provide additional geophysical constraints on these models, we performed...
Article
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P- and S-wave seismic tomography detect a low-velocity anomaly in the upper mantle beneath the Betic Cordillera and the Alborán Sea region. The anomaly is associated with the intermediate-depth seismicity (h < 110 km) in the region. This structure is interpreted as a result of an active continental subduction. Gravity modeling and seismic attenuati...
Article
To investigate the relationship between shallow and intermediate-depth earthquakes and the crust and upper mantle structure beneath the Betic-Cordillera and Alboran sea region, we have applied seismic tomography to 2569 P-wave arrival times from 367 microearthquakes recorded by both permanent and temporary seismic stations deployed in the region. T...
Article
In this study we used relatively velocity independent methods (Wadati diagrams) to estimate and check the focal depth of the seismic activity in a sector of the Betic Cordilleras-Alboran Sea in Southern Spain. To understand the behaviour of the seismic activity, a total of 335 earthquakes have been analyzed. The most interesting feature found in th...
Article
Group velocity dispersion measurements of Rg waves generated either by blasts or by local earthquakes are used to investigate the shallow crustal structure of Almería (southern Spain). In principle, the usable frequency range of 250 to 2000 mHz allows determination of structures to depths of about 4 km. For this purpose, the main operations are a d...
Article
Ninety-five microearthquakes of the Granada basin (southern Spain) with duration magnitudes ranging from 1.3 to 3.5 (moment magnitude from 0.9 to 2.5) have been spectrally analyzed with digital recordings from ten stations of the Andalusian Seismic Network. The coda-Q quality factor, Qc (assumed to be frequency dependent) was used instead of Qβ for...
Article
Full-text available
Chapter
In many places of the world it is likely that a strong earthquake will occur, and recently many countries have experienced such earthquakes and the consequent destruction and deaths. It is therefore largely accepted that programs for earthquake hazard reduction be made an urgent priority for the highly hazardous regions; however, this frequently ma...
Article
The three point method (TPM) has been successfully applied to several seismic series and has provided information about the spatial characteristics (azimuth and dip) of the fault planes activated in the rupture process. A new development of the TPM to determine temporal characteristics, is presented, to obtain the evolution of the