Person: García Mayordomo, Julián
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First Name
Julián
Last Name
García Mayordomo
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Area
Geodinámica Interna
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48 results
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Publication Evaluación regional de inestabilidades de ladera por efecto sísmico: Mapas de desplazamiento de Newmark para la Cuenca de Lorca (SE España)(Sociedad Geológica de España., 2008) Rodríguez Peces, Martín Jesús; García Mayordomo, Julián; Azañón, J.M.El sureste de España está caracterizado por una sismicidad de baja a moderada magnitud. Sin embargo, los terremotos de baja magnitud (Mw=4.0-4.5) pueden producir daños significativos en las edificaciones, así como inestabilidades de ladera (caída de rocas, principalmente). En este trabajo se presenta un mapa de desplazamientos de Newmark para la Cuenca de Lorca considerando diferentes escenarios sísmicos. Para su construcción se ha elaborado un mapa litológico basado en los mapas geológicos del IGME, asignando a cada unidad valores de peso específico, cohesión y ángulo de fricción obtenidos de bibliografía y de ensayos geotécnicos. Estos mapas se combinan con el mapa de pendientes generado a partir de un modelo digital de elevaciones (MDE) para obtener un mapa de factores de seguridad estáticos. Combinando éste con el de pendientes se obtiene el mapa de aceleraciones críticas (ac) que representa la susceptibilidad sísmica al deslizamiento. Se han considerado varios escenarios sísmicos para los que se ha aplicado factores de amplificación del terreno y topográfico para obtener los mapas de aceleración sísmica máxima (PGA). Los desplazamientos de Newmark (DN) se obtienen empleando una ecuación empírica en función del ratio K (ac/PGA). Los mapas obtenidos permiten identificar las áreas de potencial riesgo en la Cuenca de Lorca. En general, las inestabilidades esperables serán de tipo desprendimiento, particularmente caídas de rocas.Publication Estimación de la localización y la magnitud de terremotos pre-instrumentales a partir de análisis retrospectivos de inestabilidades de ladera: el caso del deslizamiento de Güevéjar (Granada)(2011) Rodríguez Peces, Martín Jesús; García Mayordomo, Julián; Azañón, J.M.; Insúa Arévalo, Juan Miguel; Jiménez Pintor, J.El estudio de detalle de inestabilidades de ladera provocadas por terremotos representa una nueva herramienta para la estimación de la localización epicentral y la magnitud de eventos sísmicos pre-instrumentales. En este trabajo se reconstruye las condiciones previas al terremoto del deslizamiento de Güevéjar, localizado en la Cuenca de Granada. Esta gran inestabilidad de ladera se reactivó durante los terremotos de Lisboa en 1755 y de Arenas del Rey en 1884. Para cada caso se ha calculado la aceleración sísmica mínima necesaria para desencadenar la inestabilidad y, a partir de este dato, se ha inferido la localización epicentral y la magnitud más probables para cada evento sísmico. Los resultados sugieren que la magnitud momento del terremoto de Lisboa en 1755 fue de al menos 8.5 y que se localizó a 580 km del deslizamiento. Para el terremoto de Arenas del Rey en 1884, se obtuvo que su magnitud momento fue de al menos 6.5 y que se localizó en los primeros 55 km alrededor del deslizamiento. En este caso, se confirma que la Falla de Ventas de Zafarraya pudo ser la fuente sismogénica de este evento sísmico. [ABSTRACT]Slope stability back-analysis performed for earthquake-triggered landslides provides additional constraints on the size and location of pre-instrumental seismic events. In this paper we reconstruct the pre-earthquake conditions of a major landslide located in the Granada Basin –the Güevéjar landslide, which was triggered twice by the 1755 Lisbon and 1884 Arenas del Rey earthquakes. For each case the minimum seismic acceleration needed to trigger the instability has been calculated, and from this datum the most likely magnitude and epicentral location has been inferred for each event. Our results suggest that the moment magnitude of the 1755 Lisbon earthquake was at least 8.5 and that it was located as far as 580 km from the landslide. For the 1884 Arenas del Rey earthquake we conclude that its moment magnitude was at least 6.5 and that it was located within the first 55 km around Güevéjar. These results support the Ventas de Zafarraya Fault as the seismogenic source of the event.Publication La Base de Datos de Fallas Activas en el Cuaternario de Iberia (QAFI v.2.0)(Universidad Complutense de Madrid, 2012) García Mayordomo, Julián; Insúa Arévalo, Juan Miguel; Martínez Díaz, José J.; Jiménez Díaz, Alberto; Martín Banda, Raquel; Martín Alfageme, Santiago; Álvarez Gómez, José Antonio; Rodríguez Peces, Martín Jesús; Pérez López, Raúl; Rodríguez Pascua, Miguel Angel; Masana, E.; Perea Manea, Hector; Martín González, Fidel; Giner Robles, Jorge; Nemserb, Eliza S.; Cabral, JoaoLa Base de Datos de Fallas Activas de Iberia (QAFI) es una iniciativa promovida por el Instituto Geológico y Minero de España (IGME) para construir un repositorio público de información científica sobre fallas con actividad en los últimos 2,59 Ma (Cuaternario). Además, la QAFI persigue establecer una base sobre la que facilitar la transferencia de conocimiento geológico al ámbito tecnológico de la gestión del riesgo sísmico en Iberia, en particular en la identificación y caracterización de fuentes sismogénicas tipo falla. La QAFI se ha construido a partir de la información proporcionada de modo altruista por más de 40 investigadores en ciencias de la Tierra conteniendo actualmente un total de de 262 registros. En este artículo se describe la concepción y evolución de la base de datos, y su arquitectura interna. Además, se ofrece un primer análisis global de los datos que contiene, con especial interés en parámetros tan importantes como la longitud y tasa de deslizamiento de las fallas. Finalmente se discuten dos temas cruciales en cualquier base de datos: su completitud y la homogeneidad de los datos. Se concluye que QAFI v.2.0, pese a ser la fuente más actualizada de información disponible en Iberia sobre peligrosidad sísmica de fallas concretas, dista aun de ser completa, por lo que nuevas revisiones y versiones deberán seguir llevándose a cabo en el futuro.Publication SeriesBuster: a Matlab program to extract spatio-temporal series from an earthquake database(Elsevier, 2005) Álvarez Gómez, José Antonio; García Mayordomo, Julián; Martínez Díaz, José J.; Capote del Villar, RamónPublication Fallas activas y sismicidad en las partes altas de la ciudad de Granada: comportamiento dinámico de la Formación Alhambra(2011) Azañón, J.M.; Rodríguez Peces, Martín Jesús; García Mayordomo, Julián; de Justo Alpañes, J.L.En este trabajo se caracteriza el comportamiento dinámico de la Formación Alhambra mediante un análisis de estabilidad del Tajo de San Pedro, localizado al pie del monumento de la Alhambra (Granada). La Formación Alhambra está formada principalmente por conglomerados de edad Plioceno-Pleistoceno inferior con un espesor de al menos 200 m. En esta formación se localizan numerosas fallas normales con dirección NO-SE predominante. Muchas de estas fallas presentan una actividad reciente, pudiendo ser relacionada con la ocurrencia de terremotos en la zona. La peligrosidad de estos eventos sísmicos debe ser considerada como moderada, ya que existen numerosos registros históricos en los que los daños producidos en los muros de la Alhambra son relacionados con la actividad sísmica. Por otra parte, estas fallas también representan discontinuidades mecánicas que contribuyen a la reducción de la estabilidad del conjunto del macizo rocoso. Este es el caso del Tajo de San Pedro, cuyo escarpe lateral constituye el plano de una de estas fallas. Los conglomerados de la Formación Alhambra son un sustrato rocoso firme y resistente con valor de aceleración crítica elevado (ac=0.51g), lo que evita que se produzcan importantes inestabilidades de ladera de origen sísmico. [ABSTRACT]We study the dynamic behaviour of the Alhambra Formation by means of a slope stability analysis of the Tajo de San Pedro slope, which is located at the bottom of the Alhambra monument (Granada). The Alhambra Formation is formed mainly by conglomerates of Pliocene to Lower Pleistocene age, and has a thickness of at least 200 m. This formation is affected by a number of normal faults trending NW-SE. Many of these faults show evidence of recent activity and so they could be responsible of the occurrence of past earthquakes in the area. In fact, damage to the walls of the Alhambra has been related many times to the occurrence of earthquakes. Additionally, these faults also play as mechanical discontinuities that contribute to reducing the stability of the rock mass. This is the case of the Tajo de San Pedro slope, one of its lateral faces being a fault scarp. The conglomerates of the Alhambra Formation are a firm and resistant bedrock that shows a high critical acceleration value (ac=0.51g), which reduces the likelihood of a instability triggered by an earthquake.Publication An Overview of the Damaging and Low Magnitude Mw 4.8 La Paca Earthquake on 29 January 2005: Context, Seismotectonics, and Seismic Risk Implications for Southeast Spain(Seismological Society of America, 2007) Benito, Belén; Capote del Villar, Ramón; Murphy, P.; Gaspar Escribano, Jorge M.; Martínez Díaz, José J.; Tsige Beyene, Meaza; Stich, Daniel; García Mayordomo, Julián; García Rodríguez, M.J.; Jiménez, M. E.; Insúa Arévalo, Juan Miguel; Álvarez Gómez, José Antonio; Canora Catalán, CarolinaThis article presents an overview of the La Paca earthquake of magnitude mbLg 4.7, which occurred on 29 January 2005, with its epicenter located near the town of Avile´s in the Murcia region in southeast Spain. Despite its low magnitude, the earthquake caused important damage in two towns of the epicentral area, La Paca and Zarcilla de Ramos. These areas recorded intensities of VI–VII (European Macroseismic Scale, 1998) and sustained estimated economic losses amounting to 10 million €. Aftershocks continued for more than 2 weeks, producing considerable alarm in the population and mobilizing emergency services from the whole region. The La Paca seismic series is the third registered in the region in the past 8 years, being preceded by the Mula (1999) and southwest Bullas (2002) seismic series. These main events had also low magnitudes (mbLg 4.8) and caused damage levels similar to the 2005 earthquake. The case is an example of a moderate seismic zone where low-magnitude and frequent earthquakes have important implications on the seismic hazard and risk of the region. Although these are not the largest expected earthquakes, they have yielded important information for improving the knowledge of the seismic activity of the area. With this aim in mind, different topics have been analyzed from a multidisciplinary perspective, including seismicity, local tectonics and surface geology, focal mechanisms, macroseismic effects, and ground motion. Results indicate a local tectonic interpretation, consistent with a strike-slip focal mechanism, the confirmation of a triggering process between the 2002 and 2005 earthquakes, a geotechnical and ground-motion characterization for the damaged sites (supporting local amplification effects and estimated peak ground acceleration values ∼ 0.1g), and an understanding of damage patterns in relation to local building trends. The results may be used as guidelines for future revisions of the Spanish Building Code (Norma de la Construcción Sismorresistente Espan˜ola [NCSE-02], 2002). The study results should contribute to risk mitigation in a region where strong-motion records from the maximum expected earthquakes are not available. This approach can be extended to other regions with similar seismic backgrounds and a lack of strong-motion records.Publication Influencia de las condiciones dinámicas en el diseño de medidas de estabilización de laderas: el caso del deslizamiento de Diezma (Granada)(2011) Rodríguez Peces, Martín Jesús; Azañón, J.M.; García Mayordomo, Julián; Troncoso, E.; Tsige Beyene, MeazaEn este trabajo se ha analizado la eficacia de las medidas de estabilización de taludes en un área activa sísmicamente. Este análisis se ha realizado tanto en condiciones estáticas como dinámicas, considerando las aceleraciones símicas más probables para el emplazamiento. Para ello se ha realizado un análisis de estabilidad retrospectivo de un deslizamiento complejo (el deslizamiento Diezma) ubicado en el sur de España utilizando datos geotécnicos, geofísicos y geológicos de detalle. Los factores desencadenantes fueron la presencia de un nivel freático somero y la reducción de la resistencia al corte de los niveles de arcilla de alta plasticidad a valores residuales. En el 2010, tras casi 10 años desde la instalación de las medidas de estabilización, se produjo una nueva reactivación del deslizamiento relacionada con un mal funcionamiento de la primera línea de pozos de drenaje profundo. La segunda y tercera línea de pozos y la barrera de pilotes anclados parecen funcionar con eficacia, deteniendo el avance del deslizamiento hacia el pie de la ladera. Sin embargo, la reactivación del deslizamiento de Diezma es esperable en el caso de que un terremoto de baja magnitud, relativamente frecuentes en la zona, se produzca cerca del deslizamiento. [ABSTRACT]In this paper the effectiveness of slope stabilization measures in a seismic active area have been analysed. A complete failure analysis of a complex landslide located in Southern Spain (the Diezma landslide) has been performed using detailed geotechnical, geophysical and geological data. The triggering factors were a shallow water table and the reduction of the shear strength parameters of the high-plasticity clay levels to residual values. The 2010 landslide reactivation was related to a bad performance of the first line of deep drainage wells. The second and third line of wells and the anchored piles barrier seem to work effectively by stopping the landslide from reaching the toe of the slope. However, the reactivation of the Diezma landslide is expected in the case that a low magnitude earthquake, relatively common in the study area, occurs close to the landslide location.Publication Seismic hazard of the Granada Fault(Asociación Española para el Estudio del Cuaternario y Sociedad Española de Geomorfología, 2013) Azañón, J.M.; García Mayordomo, Julián; Insúa Arévalo, Juan Miguel; Rodríguez Peces, Martín JesúsThe City of Granada is placed at the margin of a flat area known as the Granada Basin (Betic Cordillera, SE Spain) surrounded by mountains. The seismic activity in the Granada Basin is high, with a large number of earthquakes, all of them of moderate to low magnitude (mb ≤ 5.5). Historically, earthquakes in this area have produced important material damage and human casualties; however, it is hard to evaluate their magnitude. Seismicity has its origin mostly at depths between 5 and 17 km and the focal mechanisms indicate a present stress field dominated by a tensional tensor with an associated NE-SW extensional axis. The sedimentary cover of the Granada Basin is mostly coeval with the activity of faults that bound the basin, which have controlled the stratigraphic architecture. These faults are normal, mostly with a NW-SE orientation, and dipping towards the SW. Basinwards migration of the extensional front has exhumed the footwalls of older faults, uplifting the previous Tortonian sedimentary cover, which presently outcrops as emerged ranges at the margins of the basin. This work presents preliminary results of a paleoseismic study of the Granada Fault, an NW-SE active normal fault that produces a Plio-Quaternary throw of 300 m. According to these data, slip rate has been estimated in 0.38 mm/yr. Several paleosoils, Pleistocene in age, have been affected by this fault. These paleosoils were sampled and dated using the thermoluminiscence method to constrain these estimates. Three different seismic events can be recognized from the accumulative throw. The vertical slip per event ranges from 5 to 7 cm. Following empirical relationships, a moment magnitude between 5.9 and 6.0 can be preliminary assessed for these events.Publication Applicability of Newmark method at regional, sub-regional and site scales: seismically induced Bullas and La Paca rock-slide cases (Murcia, SE Spain)(Springer, 2011-11-27) Rodríguez Peces, Martin Jesús; Pérez García, José Luis; García Mayordomo, Julián; Azañón, José Miguel; Insúa Arévalo, Juan Miguel; Delgado García, JorgeIn this paper, the applicability of the Newmark method at regional, sub-regional and site scales has been investigated in the Lorca Basin (Murcia). This basin is located in one of the most seismically active regions of Spain. The area is very interesting for studying earthquake-induced slope instabilities as there are well-known cases associated with specific earthquakes. For the regional and sub-regional scales, a geographic information system has been used to develop an implementation of Newmark sliding rigid block method. Soil and topographic amplification effects have been particularly considered. Subsequently, ‘Newmark displacement’ maps for deterministic seismic scenarios have been produced. Some specific studies have also been performed using limit equilibrium methods to estimate the safety factor and the critical acceleration of certain slope instabilities at a site scale. These instabilities were the rock slides related to recent seismic series at the Lorca Basin: 2002 Bullas (Mw = 5.0) and 2005 La Paca (Mw = 4.8). Finally, the safety factor, critical acceleration and Newmark displacement values estimated at different scales have been compared to determine which scale is most suitable for the Newmark method.Publication Geological evidences of surface rupture related to a seventeenth century destructive earthquake in Betic Cordillera (SE Spain): constraining the seismic hazard of the Alhama de Murcia fault(Springer, 2019-03) Martínez Díaz, José J.; Alonso Henar, Jorge; Insúa Arévalo, Juan Miguel; Canora Catalán, Carolina; García Mayordomo, Julián; Rodríguez Escudero, Emilio; Álvarez Gómez, José Antonio; Ferrater, Marta; Ortuño, María; Masana, EulàliaConstraining the date of the last major event occurred in a fault is of paramount importance in probabilistic seismic hazard assessment when time-dependent models are considered. Eight of the twelve destructive earthquakes occurred in the eastern Betic Cordillera since sixteenth century, are located less than 10 km away from the Alhama de Murcia fault (AMF). Up to now, it has not been identified any geological evidence on the ground surface to associate these events with the activity of specific fault sections of the AMF. In this work we present the first geological evidence of the catastrophic 1674 event occurred at Lorca (SE Spain). The excavations carried out at La Torrecilla Creek exposed archaeological remains from the Islamic period (VIII–XIII centuries in this region) affected by 55 ± 20 cm offset by the AMF fault. This event reached intensity VIII and produced 30 fatalities at Lorca for an estimated population of 7300 inhabitants. This supports the occurrence of earthquakes with surface rupture in the historical epoch on the Alhama de Murcia fault and reinforces the results obtained in previous paleoseismological work. The theoretical scenarios of maximum magnitudes and recurrence time obtained by combining this historical event with the fault slip rate allow us to conclude that the seismic hazard associated with maximum magnitude events in this section could be high. In addition, the static Coulomb stress transferred to the Góñar–Lorca section by the 2011 (Mw 5.2) Lorca earthquake may have significantly increased the hazard.