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The study of tsunami hazard is frequently approached from numerical modelling in a deterministic or probabilistic way. When probabilistic assessments are developed, epistemic and aleatory uncertainties are taken into account and incorporated into logic-tree and Monte Carlo approaches. Our approach is based on the use of physics-based earthquake simulators, developed in recent decades to overcome the temporal limitation of the instrumental seismic catalogue in probabilistic seismic hazard assessment (PSHA). Recent development of numerical codes based on the rate-and-state constitutive law for fault slip and frictional behaviour (RSQSim) allows also the modelling of the short-term rupture process based on a quasi-dynamic physical approximation. We have applied this model to the Eastern Betic Shear Zone, where one of the major faults of the western Mediterranean is present, the Carboneras Fault. This fault is a left-lateral transpressive structure oriented with a length of ∼150 km, most of them offshore, and a slip rate of 1.3 mm/yr. This fault has been proposed as source of the 1522 Almeria earthquake (Int. VIII-IX) possibly related to a local tsunami. We present tsunami simulations from seismic ruptures of a 1 Myr synthetic seismic catalogue generated with RSQSim, consistent on 773,893 events with magnitudes Mw 3.3 - 7.6. The Carboneras Fault has the capacity to generate locally damaging tsunamis. The frequency - magnitude distribution of the seismic catalogue departs from the classical Gutenberg-Richter potential relation showing a bell-shaped distribution for the bigger events. The inter-event times for the maximum earthquake magnitudes are between 2000 and 6000 years., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

The seismicity in the SE Iberian Peninsula is distributed parallel to the coast in a well-developed strike-slip fracture system known as the Eastern Betic Shear Zone (EBSZ). This work focuses on the characterization of the shallow subsurface structure of the Algezares-Casas Nuevas Fault, within the Carrascoy Fault System of the EBSZ. The Carrascoy Fault borders the Guadalentín Depression to the south, which is a densely populated area with extensive agricultural activity. Therefore, this faults system represents a seismic hazard with significant social and economic implications. We have constructed two velocity-depth models based on P-wave tomography and Multichannel Analysis of Surface Waves (MASW) acquired from seismic reflection data. The resulting velocity models have allowed us to interpret the first ~250m depth and have revealed: i) the thickness of the critical zone; ii) the geometry of the Algezares-Casas Nuevas Fault; iii) the depth of the Messinian/Tortonian contact and iv) the presence of blind thrusts and damage zones under the Guadalentín Depression. Our results have also helped us to estimate an apparent vertical slip rate of 0.66±0.06m/ky for the Algezares-Casas Nuevas Fault since 209.1±6.2ka. Our results provide a methodological and backflow protocol to study the shallow subsurface of active faults, complementing previous geological models based on paleoseismological trenches, and can be used to improve the seismic hazard assessment of tectonically active regions around the world., The authors would like to acknowledge the project INTERGEO (CGL2013-47412-C2-1-P) GEO3BCNCSIC for the data access. Data are public access through SeisDARE (DeFelipe et al., 2021), dataset Martí et al. (2015). The Ministry of Education and Culture of the Republic of Indonesia is thanked for the main author’s Ph.D. scholarship (D3.2/KD.02.01/2019). JA is funded by MICINN (IJC2018-026335-I). I.P. is funded by the Spanish Government and the Universidad de Salamanca (Beatriz Galindo grant BEGAL 18/00090). IDF is funded by a FEDER-Junta de Castilla y León Postdoctoral contract (SA0084P20). We thank the GIPP-GFZ, (Germany) and Lisbon University (Portugal) for the instrumentation provided. Generalitat de Catalunya (AGAUR) grant 2017SGR1022 (GREG); EU (H2020) 871121 (EPOSSP); and EIT-RawMaterias 17024 (SIT4ME). W

Se presenta una serie de evidencias estructurales y geomorfológicas que apoyan la existencia de estructuras compresivas con actividad post-Tortoniense y que afectan a la red fluvial cuaternaria a lo largo del borde NO de la cuenca del Guadalquivir, en el sector de Palma del Río (Córdoba). Se trata de una serie de suaves anticlinales asimétricos de orientación entre ESE-ONO y ENE-OSO y vergencia norte, marcadas en el paisaje por la morfología controlada por las calcarenitas del Tortoniense Superior, posiblemente asociadas a la actividad de fallas inversas de orientación Bética ENE-OSO, y a la reactivación neotectónica de estructuras antiguas de orientación varisca. Se ha estimado una tasa preliminar de levantamiento tectónico de algunas de ellas y se describen afecciones a la red fluvial cuaternaria que apoyan la vigencia de su actividad, lo que contribuye al entendimiento del régimen tectónico actual y aporta datos de interés para los estudios de riesgo sísmico en la zona.

Classical models of fault rock architecture point to a relatively simple and symmetric architecture of a fault zone, where the fault core is a narrow foliated cataclasite (few centimeters) bounded by a thick damage zone developed cutting through host rocks. Those models are far from the studied fault rocks developed in the Alhama de Murcia Fault (AMF), SE Spain, where fault core is in contact with an almost no deformed hosting rock at one side and to a wide damage zone towards the opposite boundary. The AMF is an active shear zone and the source of destructive recent and historical earthquakes. It has more than 10 km accumulated slip, and it develops a more than 100 meters wide shear zone with fault rocks that have been continuously sampled and analyzed combining a drill core from a 174 m deep vertical borehole, six trenches excavation, and outcrop surfaces cleaning. Hand specimen and microanalyses were used to classify the fault rock in deformation domains in a strongly heterogeneous shear zone according to its lithologies and structural features. It ranges from 10 to 30 meters wide fault core, where steady strain occurs, to an intensely deformed damage zone where strain is concentrated along discrete gouge bands. Trenching also showed a surface rupture that offsets Arabic archaeological remains related to the 1674 catastrophic event occurred in Lorca (Murcia). Steady homogeneous deformation was found in the areas closest to the hanging wall, in the fault core, where Lower Paleozoic Schists are the potolith of ultrafault gouges. As deformation increased, the shear zone involved Permian-Triasic basement rocks and Miocene sedimentary rocks in heterogeneous deformation domains. In the lower domains, strain is located in anastomosing shear bands which are spatially related with a surface seismic rupture of the 1674 destructive earthquake.

The deep structure of the Alhama de Murcia Fault (AMF) is characterized by means of the analysis of surface waves identified in shallow high resolution seismic reflection data. Multichannel analysis of surface waves (MASW) is used to unravel the 2-D S-wave velocity model and image the depth geometry of the fault system. The study area includes segments of the fault located in La Salud area. Two approaches have been used to achieve a well constrained velocity model in the AMF fault zone. Conventional seismic reflection processing work flow has been used to clean the seismic data and increase its S/N ratio. Occam’s approach has been used to invert the digitized surface wave dispersion curves. 1D shear wave velocity-depth profiles were estimated in shot and CDP domains. Relatively well resolved 2D velocity-depth models were obtained by com- posite of the 1D Velocity-depth functions. These composite 2D-velocity models are able to constrain the depth geometry of the fault zone up to 100 m depth. The fault zone is indicated by a relatively broad low velocity anomaly that correlates with the fault’s surface expression.

Resumen En este trabajo se presentan los principales resultados de los estudios de paleosismología realizados en trincheras excavadas en la falla Cocorí, ubicada en el sector sur de la Zona Transpresiva de Cartago, en las cuales se determinó por medio de dataciones Carbono 14, deformaciones anteriores a 28000 años y posteriores a 10000 años (final del Pleistoceno Superior y el Holoceno). La deformación observada corresponde con fallas inversas con componente de rumbo, presumiblemente izquierda. También se observó deformación plástica, donde los anticlinales muestran vergencia al sur. Dos de las fallas determinadas tienen desplazamientos del orden métrico, y se definieron varios plegamientos con amplitudes cercanas al metro. Sin embargo, el bajo ángulo de las fallas o las características dúctiles de los materiales involucrados en la deformación no favorecieron encontrar evidencia estratigráfica de rupturas cosísmicas superficiales. Esto limitó poder determinar la ocurrencia de paleosismos dentro de un rango temporal apropiado. Un modelo neotectónico esquemático incorporando dos pliegues por flexión de falla (fault-bend folds), de rumbo cercano al este-oeste, permiten explicar las características geomórficas y estructurales de la falla Cocorí. Abstract In this work we present the principal results of a paleoseismological study performed in trenches dug across the Cocorí fault, located at the southern part of the Cartago Transpression Zone. Based on radiocarbon dating we define tectonic deformations occurred before the last 28000 years and after 10000 years (last part of the Upper Pleistocene and Holocene). The tectonic deformations observed in the trenches are thrust faults with a strike-slip component, probably sinistral. We also defined plastic deformation, where the anticlines show south vergence. Two of the faults had metric displacements and various folds had nearly metric amplitudes. However, the low angle of the faults and the ductile behavior of the materials involved in the deformation, do not allowed us to find evidence of coseismic surface ruptures. This limitation implied that we do not being able to temporally bracket the occurrence of any paleoearthquake. A schematic neotectonic model of two fault-bend folds, trending nearly east-west, allows us to explain the geomorphological characteristics of the southern sector of the Cartago Transpression Zone and the structural observations found in the different trenches.

European Geosciences Union General Assembly (2017. Viena), Since the Quaternary Active Faults Database of Iberia (QAFI) was released in February 2012 a number of studies aimed at producing seismic hazard assessments have made use of it. We will present a summary of the shortcomings and advantages that were faced when QAFI was considered in different seismic hazard studies. These include the production of the new official seismic hazard map of Spain, performed in the view of the foreseen adoption of Eurocode-8 throughout 2017. The QAFI database was considered as a complementary source of information for designing the seismogenic source-zone models used in the calculations, and particularly for the estimation of maximum magnitude distribution in each zone, as well as for assigning the predominant rupture mechanism based on style of faulting. We will also review the different results obtained by other studies that considered QAFI faults as independent seismogenic-sources in opposition to source-zones, revealing, on one hand, the crucial importance of data-reliability and, on the other, the very much influence that ground motion attenuation models have on the actual impact of fault-sources on hazard results. Finally, we will present briefly the updated version of the database (QAFI v.3, 2015), which includes an original scheme for evaluating the reliability of fault seismic parameters specifically devised to facilitate decision-making to seismic hazard practitioners., Instituto Geológico y Minero de España, España, Facultad de Ciencias Geológicas, Universidad Complutense de Madrid, España

En este trabajo se presenta el estudio de los parámetros mecánicos de la roca de falla (fault gouge) de la falla de Alhama de Murcia (FAM) próxima al bloque levantado. Esta falla es una de las más activas de la Península Ibérica y destaca por tener segmentos con un espesor de roca de falla (FG) exhumada de 50-80 m de espesor en régimen frágil. Su composición mineralógica se compone mayoritariamente por minerales del grupo de la mica (moscovita y paragonita) y cuarzo; en la fracción arcillosa predomina la illita acompañada por caolinita. Muestra una marcada fábrica tectónica caracterizada por la orientación preferente de los minerales laminares según una textura anastomosada que controla la resistencia mecánica de la falla. Para este estudio se han tomado muestras inalteradas procedentes de dos sondeos sobre los que se han realizado distintos ensayos de esfuerzo-deformación considerando diferentes orientaciones de los esfuerzos respecto a la fábrica. El ángulo de fricción (φ) varía desde valores mínimos (16ᵒ-26ᵒ) para los planos de rotura orientados favorablemente a la fábrica tectónica hasta valores máximos (>50ᵒ) para los planos orientados desfavorablemente. Estos elevados valores fueron obtenidos también en muestras remoldeadas de FG sin orientaciones preferentes.

[EN] We present here a geometrical analysis of a structure related to the reactivation of the NE end of the Alhama de Murcia Fault (Eastern Betic Shear Zone, SE Spain) due to the NW-SE convergence initiated iin the Upper Miocene. Conventional techniques of structural analysis have been used to estimate a net slip rate of 0.13 – 0.18 mm/yr in the Alhama de Murcia – Alcantarilla segment. The maximum expected magnitude of earthquakes from the fault segment dimensions is between MW 6.5 - 6.6, following empirical regressions, with a recurrence interval between 7,300 - 14,100 years for the slip rate obtained. The low geomorphologic expression observed in this sector of the Alhama de Murcia Fault compared to other segments shows a lower activity rate as well as the results obtained suggest the influence of the Carrascoy Fault on the regional shortening rate distribution, [ES] En este trabajo se presentan los resultados del análisis geométrico de una estructura asociada a la reactivación del extremo NE de la Falla de Alhama de Murcia (Zona de Cizalla de las Béticas Orientales) por la convergencia NO-SE iniciada en el Mioceno Superior. A partir de técnicas de análisis estructural convencionales se ha estimado una tasa de deslizamiento neto de entre 0,13 y 0,18 mm/año en el segmento Alhama de Murcia – Alcantarilla. La magnitud máxima de un terremoto cuya fuente fuese este segmento se encuentra entre MW 6,5 - 6,6, estimada mediante correlaciones empíricas, con un periodo de recurrencia comprendido entre 7300 y 14100 años para la tasa de deslizamiento obtenida. La menor expresión geomorfológica observada en este sector de la Falla de Alhama de Murcia en comparación con otros segmentos de la misma evidencia un menor grado de actividad, al mismo tiempo que los resultados obtenidos sugieren la contribución de la Falla de Carrascoy en la repartición de la tasa de acortamiento regional entre ambas estructuras., Trabajo financiado por el proyecto CGL2013-47412-C2-1-P (Ministerio de Economía y Competitividad).

The convergence between Nubian and Eurasian plates in the Western Mediterranean is being accommodated by the Eastern Betic Shear Zone, located in Southeastern Iberia. This is a low strain region whose faults show low slip rates and long recurrence periods of their maximum earthquakes, so they do not provide clear evidence of their seismogenic activity. The Alhama de Murcia - Alcantarilla segment, defined as the NE end of the Alhama de Murcia Fault, is one of the structures of the Eastern Betic Shear Zone and there are few in-depth studies about its seismic potential. In order to assess the seismogenic potential and slip-rate of this segment we have carried out a structural analysis. We have built a 3D geological model of the area where the fault is currently bounding the Neogene Fortuna basin. The structural model is based on seismic reflection profiles which have been later input in MOVE, structural modelling and analysis software. The analysis of the model has revealed several structural features related to positive inversion tectonics in Fortuna basin, specifically a typical "harpoon" structure whose deformation is estimated to have begun since Upper Miocene (Messinian). Geometric models and area balance methods (e.g. depth-to-detachment method) applied to the previously mentioned structure have allowed to estimate the heave of the fault, representing the amount of shortening observed in the fault section during its recent activity. The horizontal shortening rate estimated is between 0.09 and 0.26 mm/yr during the last 5.3 - 2.6 Ma. Projecting the obtained shortening onto the fault plane and considering the present regional tectonic shortening it has been possible to obtain a net slip rate between 0.13 and 0.37 mm/yr. Such parameters suggest that the Alhama de Murcia - Alcantarilla segment has less activity than other segments of the fault. The result obtained is consistent with the fact that the Carrascoy Fault, oriented parallel and located to the south of the Alhama de Murcia - Alcantarilla segment, seems to absorb part of the regional tectonic shortening. That is why the relief uplifted by the Alhama de Murcia - Alcantarilla segment during the Quaternary is significantly less prominent than the mountains fronts generated by the Carrascoy Fault. Even so, Alhama de Murcia - Alcantarilla segment should be considered as an active structure with implications for seismic hazard. The maximum size of earthquake is calculated to be Mw 6.3 - 6.6 according to magnitude-area and magnitude-length scaling relationships, with a mean recurrence interval lower than 10.000 years for the slip rate obtained. In the same way, Mw 5.0 earthquakes, such as those recorded in the historical seismic catalog, are estimated to have a recurrence interval lower than 50 years. These earthquakes could be very destructive in densely populated areas, as is the case of SE Spain, so they should be considered in seismic-hazard analysis.

Trabajo presentado en la European Geosciences Union General Assembly, celebrada en Viena (Austria), del 23 al 28 de abril de 2017, Here we present the results of the mechanical and mineralogical study of the fault rock of the Alhama de Murcia fault. This fault is one of the most active faults in the Iberian Peninsula. It shows segments partially formed by exhumed fine grained fault rocks (fault gouge FG) with a thickness of more than 50 m developed mainly in a brittle regime. Several strength and strain tests have been carried out, both in-situ and in laboratory, considering different stress orientations in relation to the tectonic fabric. Undisturbed samples encountered from two fault observatory boreholes drilled near Lorca, (FAM-1 and FAMSIS-IGN, of 174 and 40 m depth, respectively) has been used for the laboratory tests. The FG shows a hard soil and soft rock like mechanical behavior with uniaxial compressive strength < 2 MPa and elastic moduli (E) < 12 GPa. The tenso-deformational behaviour at low confining stresses is mainly plastic, acquiring a strain-hardening behaviour at high shear strain. The FAM-FG shows a very notable tectonic fabric controlled by a frictionally weak preferential orientation of the plate like minerals arranged in an anastomosing texture that controls the mechanical strength. The results of the strength tests show the variability of the friction coefficient (µ) depending on the stress orientation in relation to this tectonic fabric. The FG exhibit mineral assemblage similar to the shicsts , suggesting that it has been developed mainly as a result of comminution mechanisms of the hanging wall protolite . The mineralogical composition of the FG contains mica minerals (muscovite and paragonite), quartz (mainly powdered) and traces of feldspar and carbonates. The predominant clay minerals are illite, paragonite, and, occasionally and some kaolinite. In some samples, it has been observed the presence of very sparse graphite and smectite. The plate like minerals are arranged in a preferred orientation (turbostatic microfabric), that surround the quartz porphyroclasts. The friction coefficient (µ) varies between very low values (0.29-0.49) for planes oriented favourably to the tectonic fabric (following the fault failure kinematic), to very high values (>1.19) for planes unfavourably oriented.

The Southern Alboran Sea, particularly the area offshore Al Hoceima Bay, presents moderate but continuous seismic activity since the Mw 6.0 1994 Al Hoceima earthquake. The maximum magnitude occurred in the area was a Mw 6.3 earthquake in the 2004 Al Hoceima – Tamasint seismic series. Since then, the seismicity in the Al Hoceima area has been usual, with maximum seismic magnitudes around 4. An increase in the seismic rate was registered during 2015, especially from May, culminating in the seismic series in January 2016. The mainshock occurred on January 25th 2016 with a magnitude Mw 6.3 and it was preceded by a Mw 5.1 foreshock on January 21st. The seismic series took place at the western end of the Alboran Ridge. Towards the northeast the Alboran Ridge bends, and seems to be connected with the NW-SE right-lateral transtensional Yusuf Fault. The recorded seismicity is mainly located in the Alboran Ridge area and along the N-S Al-Idrisi Fault that seems to continue southwards, towards the Al Hoceima Bay. The focal mechanisms calculated previously in the area showed a leftlateral strike-slip faulting with some normal component in the Alboran Ridge; but always within a complex system of diffuse deformation and high rupture type variability. We have used 41 computed focal mechanisms of this seismic series to analyze its seismotectonics and structural characteristics. To group the focal mechanisms we used a clustering algorithm using the spatial distribution of the events and also the type of rupture mechanism. For each cluster we have obtained the composed focal mechanism, associating it to a particular fault or family of structures. We have tested the mechanical compatibility of these structures by Coulomb Failure Stress transfer modeling. The mainshock of the series occurred in the Al Idrisi Fault intersecting the western Alboran Ridge. This event triggered aftershocks and independent series in left-lateral strike-slip faults associated with the Al Idrisi Fault System towards the south, but also in near pure reverse faults in the fault zone bounding the the Alboran Ridge. Both types of faults and rupture-mechanisms coexist, linked mechanically by stress transfer, being coeval the uplift of the Alboran Ridge and its northwestward displacement due to the left-lateral motion of the Al-Idrisi Fault. It is also discussed how the contrasting faulting processes and seismic ruptures are developed in two differentially oriented fault zones in the context the current NW-SE plate convergence between the African and Eurasian plates in the Westernmost Mediterranean.

The Central American Volcanic Arc (CAVA) is located at the western margin of the Caribbean plate, over the Chortís Block, spanning from Guatemala to Costa Rica. The CAVA is associated to the subduction of the Cocos plate under the Caribbean plate at the Middle America Trench. Our study is focused in the Salvadorian CAVA segment, which is tectonically characterized by the presence of the El Salvador Fault Zone (ESFZ), part of the western boundary of a major block forming the Caribbean plate (the Chortis Block). The structural evolution of the western boundary of the Chortis Block, particularly in the CAVA crossing El Salvador remains unknown. We have done a kinematic analysis from seismic and fault slip data and combined our results with a review of regional previous studies. This approach allowed us to constrain the tectonic evolution and the forces that control the deformation in northern Central America. Along the active volcanic arc we identified active transtensional deformation. On the other hand, we have identified two deformation phases in the back arc region: A first one of transpressional wrenching close to simple shearing (Miocene); and a second one characterized by almost E-W extension. Our results reveal a change from transpressional to transtensional shearing coeval with a migration of the volcanism towards the trench in Late Miocene times. This strain change could be related with a coupled to decoupled transition on the Cocos – Caribbean subduction interface, which could be related to a slab roll-back of the Cocos Plate beneath the Chortis Block. The combination of different degrees of coupling on the subduction interface, together with a constant relative eastward drift of the Caribbean Plate, control the deformation style along the western boundary of the Chortis Block.

[ES] Se han registrado variaciones del contenido de CO2 en la Sima de Benis (Cieza, Murcia, SE de España), a una profundidad de 280m en la Sala de las Nubes durante los primeros 6 meses de 2015. El objetivo es analizar las variaciones de CO2 con la micro-sismicidad en la zona. Para ello, se ha colocado un registrador de dióxido de carbono de tipo SENSAIR cuya frecuencia de muestreo es de 40 minutos. Se ha correlacionado los incrementos diarios en este gas con terremotos, obteniendo aumentos en 24h de hasta 300 ppm sobre un valor total cercano a 2000 ppm, en relación a terremotos localizados a menos de 15 km de la boca de la cavidad, cuya magnitud estimó el Instituto Geográfico Nacional en M3. Esta cavidad, que afecta a materiales carbonatados del Prebético Externo, se desarrolla a partir de una falla con evidencias de paleoterremotos durante el Pleistoceno Superior. Independientemente de su capacidad sismogénica, los datos muestran un aumento en la difusión y movilidad del CO2 al tránsito de ondas sísmicas., [EN] The Benis Cave is the deepest explored cave (-320m) affecting the Prebetic units of the Betic Cordillera, and it was related to an active fault. Evidence of Upper Pleistocene paleoseismic activity and the peculiar topography of the cave, hypogenic and fault-related halls, encouraged us to monitor the daily CO2 content in the air composition at depth (280m), and for a time period of six months during the early 2015. Our results show a preliminary positive correlation between micro-seismic activity in the surroundings (up to 60 km away), and the CO2 concentration (daily increasing till 300ppm for the closest microearthquakes). The maximum value of carbon dioxide recorded inside the cave was c.a. 2000 ppm, and the origin was established as pedogenic from the 13CO2 analysis. Therefore, we propose an increase in the CO2 concentration into the air karst related to the micro-seismic activity. Despite this preliminary worthy results, more data are needed to establish an accurate model for earthquake forecasting., Este trabajo ha sido financiado por los proyectos CGL2013-47412-C2-2-P, CGL2013-47412-C2-1-P y CGL2013-43324-R. Además, sus conclusiones se enmarcan dentro del proyecto CGL2012-37281-C02.01 y CGL2015-67169-P.

We present the preliminary results of the borehole FAM-1 a 175 m depth scientific drilling of the Alhama de Murcia fault. The borehole was drilled close to La Torrecilla rambla three km SW of Lorca where the fault zone shearing is more concentrated and it is dominated by well-developed clay rich fault gouge. To select the drilling point and to perform a prognosis of it, three trenches were excavated crossing the fault zone that allowed us to determine the detailed 3D structure of the fault zone. We have collected more than 100 m of unaltered high quality fault rock to be studied using mineralogical and microtectonic analysis, and geomechanical testing that will improve the knowledge of the influence of tectonic microfabric and mineralogy in the seismogenic behavior of the AMF. The borehole FAM-1 and the seismic monitoring borehole FamSis-1 constitute the first stage of a future geological-geophysical observatory for monitoring the activity of the AMF.

El terremoto principal de la serie sísmica tuvo lugar el 25 de enero de 2016, con una magitud Mw 6.3, que fue precedido por un premonitorio de magnitud Mw 5.1 el día 21 de enero. Hemos utilizado 41 mecanismos focales para analizar las características sismotectónicas y estructurales de la serie. Para agrupar los mecanismo focales hemos utilizado un algoritmo de agrupamiento jerárquico espacial y por el tipo de rotura del mecanismo. De cada agrupación hemos obtenido el mecanismo focal medio y lo hemos asociado a una estructura o familia de estructuras. Hemos comprobado la compatibilidad mecánica de estas estructuras mediante transferencia de esfuerzos de Coulomb. El evento principal de la serie se produjo en la Falla de Al Idrisi intersectando la cresta de Alborán. Este evento disparó réplicas y series independientes en fallas de desgarre asociadas al sistema de Falla de Al Idrisi hacia el sur, pero también en fallas inversas asociadas al levantamiento de la Cresta de Alborán hacia el este; produciendose una partición de la deformación entre ambos tipos de estructuras interaccionando por transferencia de esfuerzos.

La falla de Alhama de Murcia (AMF) es una de las fallas más activas de la Península Ibérica y fue la causante del terremoto de Lorca de 2011 que significó numerosos daños materiales e incluso víctimas mortales. Esta falla oblicua en dirección NE-SO, que se extiende por más de 100 km, ha sido estudiada en superficie pero poco se sabe de su estructura en profundidad. Esto es especialmente importante para poder interpretar de forma correcta los numerosos datos paleosísmicos que se están obteniendo, ya que conocer la relación estructural en profundidad de las distintas ramas que forman la AMF es esencial. Por este motivo, y dentro del marco del proyecto InterGEO, se ha realizado una campaña de adquisición de datos sísmicos 2D a lo largo de la AMF, centrándose en los segmentos más interesantes en la zona de Lorca-Totana. Aquí se presentan los los resultados preliminares del procesado de algunos de los perfiles adquiridos en esta campaña que muestran la primera imagen estructural de la falla en profundidad y que permitirá entender el comportamiento de dicha falla, así como determinar su relevancia desde el punto de vista del riesgo sísmico.