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Reunión Ibérica sobre Fallas Activas y Paleosismología (3ª. 2018. Alicante). - 324 p., Universidad Autónoma de Madrid, España, Universidad Rey Juan Carlos, España, Universitat de Barcelona, España, Instituto Geológico y Minero de España, España

Fil: Heredia, Nemesio. Instituto Geológico y Minero de España; España. Fil: García Sansegundo, Joaquín. Universidad de Oviedo; España. Fil: Gallastegui, Gloria. Instituto Geológico y Minero de España; España. Fil: Farias, Pedro. Universidad de Oviedo; España. Fil: Giacosa, Raul Eduardo. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; Argentina. Fil: Alonso, Juan. Universidad de Oviedo; España. Fil: Busquets, Pere. Universidad de Barcelona; España. Fil: Charrier, Reynaldo. Universidad de Chile; Chile. Universidad Andrés Bello; Chile. Fil: Clariana, Pilar. Instituto Geológico y Minero de España; España. Fil: Colombo, Ferran. Universidad de Barcelona; España. Fil: Cuesta, Andrés. Universidad de Oviedo; España. Fil: Gallastegui, Jorge. Universidad de Oviedo; España. Fil: Giambiagi, Laura Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina. Fil: González Menéndez, Luis. Instituto Geológico y Minero de España; España. Fil: Limarino, Carlos Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina. Fil: Martín González, Fidel. Universidad Rey Juan Carlos; España Fil: Méndez Bedia, Isabel. Universidad de Oviedo; España. Fil: Pedreira, David. Universidad de Oviedo; España. Fil: Quintana, Luis. Universidad de Oviedo; España. Instituto Geológico y Minero de España; España. Fil: Rodríguez Fernández, Luis. Universidad de Oviedo; España. Fil: Rubio Ordóñez, Álvaro. Universidad de Oviedo; España. Fil: Seggiaro, Raul Eudocio. Universidad Nacional de Salta; Argentina. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; Argentina. Fil: Serra Varela, Samanta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentina. Fil: Spalletti, Luis Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentina. Fil: Cardo, Andrea Romina. Universidad Nacional de San Juan; Argentina. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; Argentina. Fil: Ramos, Victor Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina Fil: Giacosa, Raul Eduardo. Universidad Nacional de Río Negro. Instituto de Investigaciones en Paleobiología y Geología. Río Negro, Argentina. During the late Neoproterozoic and Paleozoic times, the Argentine-Chilean Andes -and since the late Paleozoic the Antarctic Peninsula- formed part of the southwestern margin of Gondwana. During this period of time, a set of continental fragments of variable extension and allochtonie was successively accreted to that margin, resulted in six Paleozoic orogenies of different temporal and spatial extension: Pampean (Ediacaran-early Cambrian), Famatinian (Middle Ordovician-Silurian), Chanic (Middle Devonian-early Carboniferous), Ocloyic (Middle Ordovician-Devonian), Gondwanan (Middle Devonian-middle Permian) and Tabarin (late Permian-Triassic). All these orogenies had a collisional character, with the exception of the Tabarin and the Gondwanan south of 38º S Durante el Neoproterozoico tardío y el Paleozoico, el actual segmento argentino-chileno de la Cordillera de los Andes y, desde finales del Paleozoico, la Península Antártica, formaron parte del margen suroccidental de Gondwana. Durante este periodo de tiempo, a dicho margen se fue acrecionando un conjunto de fragmentos continentales de tamaño y aloctonía variable, dando lugar en el Paleozoico a seis orogenias de diferente extensión temporal y espacial: Pampeana (Ediacárico-Cámbrico temprano), Famatiniana (Ordovícico Medio-Silúrico), Chánica (Devónico Medio-Carbonífero temprano), Oclóyica (Ordovícico Medio-Devónico), Gondwánica (Devónico Medio-Pérmico medio) y Tabarin (Pérmico tardío-Triásico). Todas estas orogenias son colisionales, salvo la Tabarin y la Gondwánica al sur de los 38º S.

El basamento ígneo-metamórfico pre-mesozoico de la Cordillera Nordpatagónica se asigna al Complejo Colohuincul. El mismo incluye rocas metamórficas de medio-alto grado ubicadas en el área de San Martín de los Andes, rocas metamórficas de bajo grado ubicadas en Cuesta de Rahue y rocas ígneas intrusivas devónicas (ca. 400 Ma). Estas rocas fueron deformadas por eventos orogénicos distintos, uno pre-Wenlock (rocas metamórficas de alto grado) y otro Carbonífero superior-Pérmico inferior (rocas metamórficas de bajo grado e intrusivos). Investigaciones previas sobre circones detríticos en las metamorfitas de la Cuesta de Rahue han arrojado edades máximas de sedimentación de 364 Ma (Devónico Superior). Nuevos trabajos de campo en la zona de San Martín de los Andes indican que las rocas metamórficas de alto grado serían roof pendants y encajantes de los cuerpos ígneos intrusivos del Devónico Inferior, por lo cual estas metamorfitas tendrían una edad anterior a ca. 400 Ma. En este trabajo presentamos nuevos datos de circones detríticos obtenidos en las metamorfitas de alto grado que permiten interpretar una edad máxima de sedimentación de 506 Ma. Esta nueva edad señala que en la zona de San Martín de los Andes se encuentra el basamento más antiguo conocido de los Andes Norpatagónicos., Instituto de Investigación en Paleobiología y Geología, Universidad Nacional de Río Negro, Argentina, Instituto Geológico y Minero de España, España, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, España, Departamento de Geología, Universidad de Oviedo, España

La Falla de Alhama de Murcia (FAM) es una falla de desgarre sinestral y cierta componente inversa, que fue la responsable del terremoto más catastrófico producido en España en los últimos 50 años, el terremoto de Lorca de 2011 (Mw 5.2). En este trabajo se presenta el estudio de dos trincheras paleosísmicas excavadas en la superficie del abanico aluvial de La Salud que se encuentra cubriendo la traza de la FAM en el sector oriental del segmento Lorca-Totana. La excavación de las trincheras se apoya en la realización de una prospección geofísica mediante tomografía eléctrica y perfiles GPR con el objetivo de obtener nuevos datos de recurrencia sísmica en esta zona de la falla. Tanto las trincheras como los datos geofísicos son coherentes con la existencia de un plano de falla buzando 30º hacia el sur que deforma visiblemente los últimos depósitos del abanico. Las trincheras nos indican la ocurrencia de entre 3 y 6 eventos paleosísmicos de ruptura superficial en los últimos 31 ky.

Hecates Tholus is a volcano located at the Elysium volcanic province in the Martian lowlands (32ºN, 210ºW). In addition to several nested calderas, the volcano shows several geological and geomorphological features that could be indicative of a complex volcanic evolution: channels, depressions, pits, faults and ridges, and a complex volcano topography. The processes that can explain the structural evolution of the volcano, include: (1) volcanic spreading, (2) lateral volcanic activity, (3) development of large landslides, (4) hydrothermal activity, and (5) tectonic deformation. We discuss these hypotheses and their implications, in order to establish the most feasible volcanic history of Hecates Tholus

Hecates Tholus is a volcano located at the Elysium volcanic province in the Martian lowlands (32ºN, 210ºW). In addition to several nested calderas, the volcano shows several geological and geomorphological features that could be indicative of a complex volcanic evolution: channels, depressions, pits, faults and ridges, and a complex volcano topography. The processes that can explain the structural evolution of the volcano, include: (1) volcanic spreading, (2) lateral volcanic activity, (3) development of large landslides, (4) hydrothermal activity, and (5) tectonic deformation. We discuss these hypotheses and their implications, in order to establish the most feasible volcanic history of Hecates Tholus

The Northwest of the Iberian Peninsula is characterised by the absence of Mesozoic sedimentary deposits, the Cenozoic sediments being scarce. Due to that, the chronology of the geological events in the area is difficult to establish. Nevertheless, in the absence of deposits during a certain time span, the thermal history a particular area during that time-elapse could have been recorded in previous materials. Modelling of the apatite fission-track (AFT) data is a powerful tool to infer geological information in this kind of regions. The tectonothermal history observed in the AFT models begins with the intrusion of the late Variscan granitic plutons and their cooling in the upper crustal levels. After this initial event, three main episodes have been identified. The first involves an important heating during the Upper Jurassic and Earlier Cretaceous, which can be related to the evolution of the Atlantic passive margin. The second heating episode can be connected to the beginning of the Europe-Africa collision during the Upper Cretaceous and the Earlier Palaeogene. Finally, a cooling episode is observed during the Paleogene, which can reflect exhumation processes according with the tectonic structures and the development of the present day topography

The Northwest of the Iberian Peninsula is characterised by the absence of Mesozoic sedimentary deposits, the Cenozoic sediments being scarce. Due to that, the chronology of the geological events in the area is difficult to establish. Nevertheless, in the absence of deposits during a certain time span, the thermal history a particular area during that time-elapse could have been recorded in previous materials. Modelling of the apatite fission-track (AFT) data is a powerful tool to infer geological information in this kind of regions. The tectonothermal history observed in the AFT models begins with the intrusion of the late Variscan granitic plutons and their cooling in the upper crustal levels. After this initial event, three main episodes have been identified. The first involves an important heating during the Upper Jurassic and Earlier Cretaceous, which can be related to the evolution of the Atlantic passive margin. The second heating episode can be connected to the beginning of the Europe-Africa collision during the Upper Cretaceous and the Earlier Palaeogene. Finally, a cooling episode is observed during the Paleogene, which can reflect exhumation processes according with the tectonic structures and the development of the present day topography

The differential stress that caused the extensional ductile shear o f Santa Ma de la Alameda during the collapse of the Variscan orogen in the Sistema Central (central Iberia) has been estimated using the dynamically recrystallized grain size of quartz. An estimate of the strain rate has been calculated by the flow laws for ductile strain of quartz knowing the deformation temperature. The stress history obtained for this shear band features 3 stages of 22-31 MPa, 34-65 MPa and 53-67 MPa. The increase o f the differential stress is caused by the concentration of the strain in smaller bands during mylonitization. The first stage can be correlated to the initial deformation of a wide shear band, the second stage can be related to the formation of two main mylonitic shears, and finally the third stage correspond to the deformation of thin (

The sinuosity of the Cuadalhorce River in the Malaga Basin is studied in this paper. The Malaga Basin is located in the Internal Zone of the Western Betic Chain, southern Spain. The river channel is divided into 5 reaches from the mouth, according to the strike variations of the valley. The sinuosity decreases dramatically in reach 2 in comparison to the sinuosity in reaches 5, 4, and 3. We interpret this lower sinuosity in reach 2 as a decrease in the slope of the valley. This fact is also observed in the longitudinal profile of the river channel along reach 2. We conclude that the anomalies observed in reach 2 are due to a gentle syncline related to the active anticline of Sierra de Cártama.

This work shows the results o f a gravimetric survey carried out in the Malaga Basin (sited on the Internal Zone o f the Western Betic Chain, southern Spain). Three anomalies maps are exposed and interpreted, focusing on neotectonic aspects. In order to avoid the influence of peridotitic bodies which outcrop in the studied area, and the southward thinning of the crust, a regional anomaly map has been processed and subtracted to the Bouguer anomaly. So, a residual anomaly map has been reached, where neotectonic interpretation has been done. The main tectonic feature evidenced by gravimetric data is the Albornoque Fault. It represents the southern boundary o f the Malaga Basin with a noticeable vertical component, according to its high gradient. By other hand, the fold o f Sierra de Cartama is marked by a maximum axis. This axis continues westward giving a duplicated depocenter of the basin. It is interpreted as a reverse fault, related in depth with the folding o f Sierra de Cartama, and which affects the basement o f the basin. According with the current stress field in the zone (NNW-SSE), the proposed structures imply the existence o f a compressive neotectonic activity, where the Albornoque fault is interpreted as a high angle reverse fault o f a reverse fault

The illite crystallinity index of Kubler (1C) has been studied to establish the conditions of the last deformation stages in the Santa María de la Alameda shear zone. For this study, it has been used mainly the fine grained fraction of the samples (less than 2 mm) which is concentrated along small brittle fractures and zones of protocataclasitic material. The studied rocks give "illite crystallinity index" values between 0.35 D°2q and 0.25 D°2q, pointing to deformation conditions at temperatures which denotes a retrograde metamorphismo zone belonging to the epizone and anquizone. These results indicate a a rétrogradation condition for the late brittle deformation stage of the Santa Maria de alameda fault, in temperatures range between 255 and 200° C

Principles of fractal geometry have been applied to the description of quartz grain borders and to the assessment of deformation temperature in milonitic rocks at the Santa Maria de la Alameda Ductile Shear Zone (Central System). This shear zone have evolved during late variscan tectonic period in a large temperature range, which goes from regional metamorphic pick conditions (Amphibolite facies) to temperatures lower than for Greenschists facies. Using fractal dimension analysis techniques and the temperature calibration performed by Kruhl y Nega (1996), have been established a temperature sequence, diminishing from around 490°C to 325°C during the simultaneous processes of milonitization and retrogressive metamorphism. These results are in agreement with temperatures obtained from deformation mechanisms in quartz and potassium feldspar showming the validity of fractal geometry method to deformation temperature assessment

Principles of fractal geometry have been applied to the description of quartz grain borders and to the assessment of deformation temperature in milonitic rocks at the Santa Maria de la Alameda Ductile Shear Zone (Central System). This shear zone have evolved during late variscan tectonic period in a large temperature range, which goes from regional metamorphic pick conditions (Amphibolite facies) to temperatures lower than for Greenschists facies. Using fractal dimension analysis techniques and the temperature calibration performed by Kruhl y Nega (1996), have been established a temperature sequence, diminishing from around 490°C to 325°C during the simultaneous processes of milonitization and retrogressive metamorphism. These results are in agreement with temperatures obtained from deformation mechanisms in quartz and potassium feldspar showming the validity of fractal geometry method to deformation temperature assessment

In this work is shown how an active fold (the Sierra de Cartama fault) is marked by the drainage pattern and topography, besides of structural data. The Sierra de Cartama fold is an asymmetric fold with double plunge and determines the shape of an elongated saw in the Western Betic Chains (South of Spain). Watching the drainage patterns, it can be noticed how streams and creeks round the saw. The uplift of the saw raise the valleys steeply, even leaving a hanging valley ("wind gap ") at the western part of the structure. Regarding to these observations, the lateral propagation of the fold seems to be toward the west. The proposed structure implies the existence of a compressive neotectonic activity in the zone. The compressive horizontal direction is N10e-30eW, perpendicular to the fold axis. In this tectonic environment it could be possible to interpret a reverse fault in deep associated with the fold growth

The Santa Maria de Alameda (Madrid) Ductile Shear Zone is a complex mylonitic belt trending east -West and dipping 30°-60° southward. The hanging wall block sinks towards the South-Southeast. Its kinematics is in relation to an extensional tectonic regime with North-south stretching direction. This large structure belongs to the early stages of the Malagon tectonic period, where important faulting and dike emplacement were produced. The shearing process was developed in retrograde metamorphic conditions in a wide range of temperature, which goes from 400° C to 150° C. The age of this deformation is constrained by the variscan regional metamorphic peak and the intrusion of late variscan granitoids (Las Navas del Marques adamellites), being therefore, between early Namurian and Stephanian

The Santa Maria de Alameda (Madrid) Ductile Shear Zone is a complex mylonitic belt trending east -West and dipping 30°-60° southward. The hanging wall block sinks towards the South-Southeast. Its kinematics is in relation to an extensional tectonic regime with North-south stretching direction. This large structure belongs to the early stages of the Malagon tectonic period, where important faulting and dike emplacement were produced. The shearing process was developed in retrograde metamorphic conditions in a wide range of temperature, which goes from 400° C to 150° C. The age of this deformation is constrained by the variscan regional metamorphic peak and the intrusion of late variscan granitoids (Las Navas del Marques adamellites), being therefore, between early Namurian and Stephanian

La determinación de las fallas capaces de disparar terremotos en zonas adyacentes con formaciones geológicas aptas para el almacenamiento profundo de gas, es una tarea que mitiga la ocurrencia de sismicidad inducida por operaciones subterráneas y movimiento de fluidos. Para ello, la determinación del campo de esfuerzos/deformación tectónicos activo ayuda a entender los patrones tridimensionales de fracturación cartografiados no solo en la zona, sino también en la propia roca almacén. Por este motivo, se presenta un protocolo de trabajo para la obtención del campo de deformación (σHmax, σhmin) que ayude a entender el papel de cada conjunto de fallas cartografiado. Para ello, aplicamos el Análisis Poblacional de fallas en dos zonas de influencia: 1) Campo cercano: 10 km de diámetro del almacenamiento y 2) Campo Lejano: 20 km de diámetro. Sobre estas zonas calculamos las trayectorias de deformación y llevamos a cabo una cartografía sistemática de fallas. Se presentan los resultados preliminares de Hontomín.

Reunión Ibérica sobre Fallas Activas y Paleosismología (3ª. 2018. Alicante). - Texto en inglés con resumen y palabras claves en inglés y español, El yacimiento de gas de Poseidón constituye uno de los campos de extracción de gas el cual se localiza en el Golfo de Cádiz. Esta zona presenta fallas sismogénicas con capacidad de generar terremotos. Es por ello que un estudio exhaustivo de la potencial sismicidad inducida por operaciones de extracción de gas permitirá avanzar en el estudio de potenciales terremotos que afecten a la zona de Huelva, Cádiz y extremo suroeste de Portugal. La energía sísmica anual liberada en el entorno cercano al almacenamiento (50 km) presenta una correlación positiva con la cantidad de gas producida según datos oficiales del Ministerio de Energía, Turismo y Agenda Digital. También se observa que dicha correlación depende de la cantidad producida al año. Con estos datos, es importante hacer un seguimiento al ser una de las zonas de mayor actividad sísmica de la Península Ibérica, con capacidad de disparar terremotos destructivos. = The offshore field gas of Poseidon is located within the Gulf of Cadiz. This area is prone to large earthquakes, including the estimated epicentre of the great earthquake of Lisbon of 1755. In this sense, the study of the potential induced seismicity in this area is a key point to be addressed plus the role of induced earthquakes and large tectonic faults. We have found a positive correlation between the annual seismic energy released 50 km away of the gas field with the gas production (data provided by the Spanish Ministry of Energy).The long-term behaviour of the seismic energy and gas production indicates that induced seismicity was present during the period of extraction and reservoir depletion., Instituto Geológico y Minero de España, España, Departamento de Geología y Geoquímica, Universidad Autónoma de Madrid, España