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This work was funded by the research project TASCUB (RTI2018- 100737-B-I00) of the Spanish Ministry of Science, Innovation and Universities, the research group VIGROB053 (University of Alicante), and the research group RNM 325 of the Junta de Andalucía. Iván Medina Cascales was funded by Ph.D. contract FPU16/00202 of the Spanish Ministry of Science, Innovation and Universities.Wewould like to thank the editor Martin Stokes, and the reviewers Francisco Moral, Pablo G. Silva, and the anonymous reviewer, whose useful comments and suggestions greatly improved the manuscript., In this work, we prove the usefulness of morphometric analyses, typically applied to basin-border faults, to define the tectonic geomorphology of a slow-moving, intrabasinal structure: the Galera Fault (Guadix-Baza Basin, southern Spain). The Galera Fault is a 30 km-long, oblique-slip fault with major left-lateral and minor vertical slip components. Through geological and structural analyses, we define for the first time the detailed surface geometry of the fault, which is characterized by features typical of left-lateral strike-slip faults. The morphometric analysis indicates that a combination of slow slip rates and the high erodibility of the juxtaposed basin infill deposits favours a rapid landscape response to fault activity that erases many landscape effects related to active tectonics. This masking is more effective on features generated by strike-slip displacement, leaving only subtle evidence, such as local stream deflections and upstream widening of catchments. In contrast, geomorphic effects related to vertical displacement are better preserved, including the control of the geometry of the main rivers and morphological differences in the drainage network between the two fault blocks. On the upthrown fault block, streams are generally shorter and steeper and have greater valley incision, leading to the development of a bad land landscape. Moreover, the vertical deformation of a Middle Pleistocene glacis surface (ca. 90 m) demonstrates the important role of this slow-moving intrabasinal fault in the generation of relief in the Betic Cordillera during recent Quaternary time. Although the impact of this fault on relief building is very low in comparison with oblique-slip, basin-border faults in the mountain range, it has a key control on the Quaternary landscape evolution., TASCUB (RTI2018- 100737-B-I00) of the Spanish Ministry of Science, Innovation and Universities, VIGROB053 (University of Alicante), RNM 325 of the Junta de Andalucía, FPU16/00202 of the Spanish Ministry of Science, Innovation and Universities

Successive excavation of 13 trenches of different orientations reveals the complexity of a normal fault zone in Pliocene-Pleistocene unconsolidated sediments on a strand of the Baza Fault, central Betic Cordillera, south Spain. These trenches and the excavation floor are interpreted and integrated to reconstruct the 3D geometry and internal architecture of the fault zone. The structure consists of two main fault strands: an eastern one with a few hundred metres throw and a western one with at least 15 m throw. These strands interact and gradually merge to the south, bounding a main deformation zone narrowing from ∼7 to 1 m along strike. Fault-bounded rock bodies, clay and sand smears, and clay injections define the structure. These features are highly variable in 3D. In the northern part of the outcrop, deformation is localized around the main strands, brittle in the west and more ductile to the east. As the strands and their fault zones increasingly interact, fault throw, rock deformation and maturity of the structure increase. Mechanical stratigraphy also controls the style of deformation. A realistic representation of this 4D picture of fault deformation is critical for modelling fluid flow in shallow to possibly deep, faulted sedimentary reservoirs. This research was founded by research group VIGROB053 (University of Alicante).

One of the most significant parameters for seismic hazard assessment analyses is the fault slip rate. The combination of both geological (long-term) and geodetic (short-term) data offers a more complete characterization of the seismic potential of active faults. Moreover, geodetic data are also a helpful tool for the analysis of geodynamic processes. In this work, we present the results of a local GPS network from the Baza sub-Basin (SE Spain). This network, which includes six sites, was established in 2008 and has been observed for seven years. For the first time, we obtain short-term slip rates for the two active faults in this area. For the normal Baza Fault, we estimate slip rates ranging between 0.3 ± 0.3 mm/yr and 1.3 ± 0.4 mm/yr. For the strike-slip Galera Fault, we quantify the slip rate as 0.5 ± 0.3 mm/yr. Our GPS study shows a discrepancy for the Baza Fault between the short-term slip rates and previously reported long-term rates. This discrepancy indicates that the fault could be presently in a period with a displacement rate higher than the mean of the magnitude 6 seismic cycle. Moreover, the velocity vectors that we obtained also show the regional tectonic significance of the Baza Fault, as this structure accommodates one-third of the regional extension of the Central Betic Cordillera. Our GPS-related slip rates form the basis for future seismic hazard analysis in this area. Our results have further implications, as they indicate that the Baza and Galera Faults are kinematically coherent and they divide the Baza sub-Basin into two tectonic blocks. This points to a likely physical link between the Baza and Galera Faults; hence, a potential complex rupture involving both faults should be considered in future seismic hazard assessment studies., We acknowledge the comments of Editor Prof. Irina M. Artemieva and two anonymous reviewers, which significantly improved the quality of this paper. This research was funded by the Spanish Ministry of Science, Innovation and University (Research Projects: RTI2018-100737-BI00 and CGL2016-80687-R), the University of Alicante (Research Project: VIGROB053), the University of Jaén (PAIUJA 2019-2020 and Programa Operativo FEDER Andalucía 2014-2020 - call made by UJA 2018), the University of Granada (B-RNM-301-UGR18) and the Junta de Andalucía regional government (RNM148, RNM282, and RNM370 and P18-RT-3275 research groups). We thank all observers who collected the data of survey-mode GPS measurements.

This study presents a mineralogical analysis of the effect of hypersaline lake environments rich in organic matter on the mineral transformations in sediments of the eastern part of the Guadix-Baza Basin (Betic Cordillera). Dark sediments with fragments of organic matter are rich in phyllosilicates (K-white mica, illite-smectite mixed layers, –I/S– minor amounts of paragonite, palygorskite, chlorite and kaolinite) and contain quartz, feldspars, and framboidal pyrite. X-ray diffraction patterns of I/S (R0 type, disordered) revealed a continuous between the positions of pure smectite and 30% of illite layers. Chemical composition of I/S mixed layers indicated a significant beidellitic substitution of Si by Al, Fe + Mg > 1 atoms per formula unit (a.p.f.u.) and K content up to 0.42 a.p.f.u. These data suggested the presence of a minor and variable amount of illitic layers among the major smectitic ones. Saline waters of the lake and the reducing environment of the sediment favored Mg and Fe uptake, generating octahedral negative charge, which together with the beidellitic substitution would provide clay layer negative charge enough to admit K incorporation in the interlayer, hence the beginning of a diagenetic low temperature illitization., This work has been financed by research projects PGC2018-094573-B-I00 and TASCUB (RTI2018-100737-B-I00) from the MCIU-AEI-FEDER, and research groups RNM-325 and RNM-179 of the Junta de Andalucía. We acknowledge the suggestions and comments from two anonymous reviewers and from the editor (Dr. M.V. Villar). María del Mar Abad is especially recognized for helping with the HRTEM and for being able of providing us the AEM analyses during the COVID-19 lockdown. The “Centro de Instrumentación Científico-Técnica of the Universidad de Jaén” is aknowledged for the use of the PANalytical Empyrean diffractometer and the Merlin Carl Zeiss electron microscope. The use of the PANalytical X'Pert Pro diffractometer of the “Departamento de Mineralogía y Petrología, Universidad de Granada, Spain” is also acknowledge. The access to the HAADF FEI TITAN G2 microscope and the Philips CM20 (STEM) microscope was facilitated by the “Centro de Instrumentación Científica of the Universidad de Granada”. The “Instituto de Recursos Naturales y Agrobiología of Sevilla, CSIC” is acknowledged for provide organic carbon analyses.

We have studied damage zones of two active faults, Baza and Padul faults in Guadix-Baza and Granada basins, respectively, in South Spain. Mineral and microstructural characterization by X-ray diffraction and field emission electron microscopy studies have been combined with structural fieldwork and in situ measurements of rock properties (permeability and Young&rsquo, s modulus) to find out the relation between deformation behavior, mineral processes, and changes in the soft rock and sediment properties produced by fluid flow during seismic cycles. Our results show that microsealing produced by precipitation of dolomite and aragonite along fractures in the damage zone of Baza Fault reduces the permeability and increases the Young&rsquo, s modulus. In addition, deformation bands formed in sediments richer in detrital silicates involved cataclasis as deformation mechanism, which hamper permeability of the sediments. In the Granada Basin, the calcarenitic rocks rich in calcite and clays in the damage zone of faults associated to the Padul Fault are characterized by the presence of stylolites without any carbonate cement. On the other hand, marly lithofacies affected by faults are characterized by the presence of disaggregation bands that involve cracking and granular flow, as well as clay smear. The presence of stylolites and deformation bands in these rocks reduces permeability.

The geometry and kinematics of active faults have a significant impact on their seismic potential. In this work, a structural characterization of the active Baza Fault (central Betic Cordillera, southern Spain) combining surface and subsurface data is presented. Two sectors are defined based on their surface geometry: a northern sector striking N–S to NNW–SSE with a narrow damage zone and a southern sector striking NW–SE with a wide damage zone. A kinematic analysis shows pure normal fault kinematics along most of the fault. Geometric differences between the northern and southern sectors are caused by i) a heterogeneous basement controlling the fault geometry at depth and in the cover; ii) different orientations of the Baza Fault in the basement with respect to the regional extension direction and iii) interaction with other active faults. We use this structural characterization to analyse the segmentation of the Baza Fault. According to segmentation criteria, the entire Baza Fault should be considered a single fault seismogenic segment. Consequently, the seismic potential of the fault is defined for a complete rupture. Magnitude for the Mmax event is calculated using several scale relationships, obtaining values ranging between Mw 6.6 and Mw 7.1. Recurrence times range between approximately 2,000 and 2,200 years for Mmax events and between 5,300 and 5,400 years for palaeo-events. A geodetic scenario modelled for an Mmax event of Mw 6.7 shows permanent vertical displacements of more than 0.40m and an overall WSW–ENE extension during entire ruptures of the Baza Fault. This work was funded by the research project TASCUB (RTI2018-100737-B-I00) of the Spanish Ministry of Science, Innovation and Universities, the research group VIGROB053 (University of Alicante), the research project AICO/2019/040 of the Generalitat Valenciana (Valencia regional government), and the research group RNM-325 of the Junta de Andalucía (Andalucia regional government). Iván Medina Cascales was funded by Ph.D. contract FPU16/00202 of the Spanish Ministry of Science, Innovation and Universities. Research partially funded by the Programa Operativo FEDER Andalucía 2014-2020-call made by the University of Jaén 2018.

The present-day relief of the Betic Cordillera formed since the Late Miocene through the regional N-S to NW-SE Africa-Eurasia convergence that developed large folds. The Laujar Fault Zone is a south-dipping E-W oriented structure located at the northern boundary of the Alpujarran Corridor Neogene intramontane basin, which separates Sierra Nevada and Sierra de Gador antiforms, in the Internal Zones of the Betic Cordillera. The fault zone acted in a first stage as a dextral strike-slip fault. Currently it moves as a normal fault evidenced by striated calcretes, also in agreement with regional continuous GPS (CGPS) data that support the hypothesis of an active N-S extension in the fault area. In order to analyse the deep geometry of the Laujar Fault Zone, we combined several geophysical techniques (gravity, magnetic, electric resistivity tomography and audio-magnetotelluric data) with field geological observations. Fault surfaces seem to join at a southward-dipping shallow detachment level, including faults covered by the sedimentary infill. The fault zone was developed in a previously weakened area by wrench faults parallel to the Alpujarran Corridor. The recent normal activity of this fault zone may be a consequence of a change in the Africa-Eurasia convergence orientation, which implies a decrease in the N-S compression component. This structure along the southern limb of Sierra Nevada antiform evidences the gravitational collapse of previously thickened crust in a regional compressional context simultaneous to metamorphic core uplift.

This study presents a mineralogical and mechanical analysis of the clay-rich materials and structures identified in the Galera Fault Zone, southern Spain that formed as a consequence of active deformation processes affecting this seismically active region. Significant differences in clay mineral assemblages and chemical composition were identified in rocks from the Galera Fault Zone, through a series of analytical techniques including XRD, SEM, TEM and XRF. Three distinct mineral assemblages were identified: 1) wall-rock assemblages including white marls and dark lutite layers, with the latter also found in injection features. Their assemblage includes dolomite, gypsum, quartz, calcite and phyllosilicates 2) smectite- and palygorskite-rich fault gouges formed on materials from the upper part of the stratigraphic sequence at the NE area of the fault (Galera Village), and 3) sepiolite-rich gouges in areas of the lower part of the stratigraphic sequence at the central SW segment of the fault (Rambla de los Pilares). Fibrous clay-rich gouges were formed by hydrothermal alteration during periods of fluid-rock interaction that was concentrated in fault planes and fractures. Their mineralogy is dominated by authigenic Mg-rich fibrous clay minerals; sepiolite, precipitated directly from an Mg-rich fluid; and palygorskite as the product of the interaction of the fluid with the Al-rich host rock. Experimental data from frictional sliding experiments on these clay-rich fault gouges reveal strong differences in their mechanical properties. Towards the north-eastern areas of the fault, the smectite- and palygorskite-rich gouge has a low friction coefficient (0.17 wet and 0.59 under vacuum) and its values of the friction stability parameter (a–b) are always positive indicating a stable regime that could be related with creeping and stable-sliding processes. In the central-south-western segment, however, the gouge is rich in authigenic sepiolite and presents complete absence of smectite. The higher friction coefficient (0.47 wet and 0.68 under vacuum) and negative values of a–b for this gouge suggest a more neutral to unstable regime that could favour earthquake nucleation.

A ~1000 m3 rockslide occurred close to Lorca (SE Spain) during the main shock (Mw = 5.1) of the May 2011 seismic sequence. The location of the rockslide, within 10 km of the earthquake epicenter and along the southern slope of a valley in which similar geological conditions occur on both slopes of the valley, suggests a significant near-field effect due to local seismic response. This could be related to the specific interaction between the topography and the obliquely propagating seismic waves. A dynamic stress strain numerical model was constructed using the FLAC 7.0 finite difference code to back analyze the Lorca rockslide event and relate its occurrence to both the local seismic amplification and the interaction between seismic waves and local topography. The results indicate that only for seismic waves with incidence angles in the range 0°–50° are the occurred slope instabilities expected. These results do not significantly change when varying the values for either stiffness or strength parameters within the range of the experimental data., This work was partially funded by research groups VIGROB-53 and VIGROB-184 (Universidad de Alicante) and by the projects tec2008–06764–c02–02 and CGL2011–30153–c02–02.

This paper on the Baza Fault provides the first palaeoseismic data from trenches in the central sector of the Betic Cordillera (S Spain), one of the most tectonically active areas of the Iberian Peninsula. With the palaeoseismological data we constructed time-stratigraphic OxCal models that yield probability density functions (PDFs) of individual palaeoseismic event timing. We analysed PDF overlap to quantitatively correlate the walls and site events into a single earthquake chronology. We assembled a surface-rupturing history of the Baza Fault for the last ca. 45,000 years. We postulated six alternative surface rupturing histories including 8–9 fault-wide earthquakes. We calculated fault-wide earthquake recurrence intervals using Monte Carlo. This analysis yielded a 4750–5150 yr recurrence interval. Finally, compared our results with the results from empirical relationships. Our results will provide a basis for future analyses of more of other active normal faults in this region. Moreover, our results will be essential for improving earthquake-probability assessments in Spain, where palaeoseismic data are scarce. This research was founded by the Spanish Ministry of Economics, Industry and Competitiveness (MINECO) research Projects CGL2011-30153-C02-02 and EPILATES (CGL2015-65602-R). Also by the research group VIGROB053 (University of Alicante), the research Project UJA2014/06/17 (Caja Rural de Jaén and University of Jaen) and the research contract 2015CL015 (University of Jaen).

On February 23, 2015, an earthquake of magnitude Mw 4.7 (Imax = V, scale EMS) struck the center of the Spain, triggering dozens of instabilities in taluses and natural slopes of an area characterized by low relief. These instabilities were characterized by: (1) very small size, most of them with volumes lower than 1 m3, and (2) to occur in rock masses affected by multiple discontinuities, which pre-defined blocks that fell down during the shaking. The inventory of instabilities of this earthquake has shown that most of the instabilities occurred on the slopes of the road network, although the larger instabilities were observed in natural slopes. The comparative analysis of this inventory with those made for other recent earthquakes occurred in the SE of Spain (1999, 2002, 2005 and 2011), all of them of similar magnitude Mw (between 4.7 and 5.1), allow to recognize that the vast majority of instabilities induced by these earthquakes were rock/soil falls, being other typologies of landslides very rare. In all cases, the size of instabilities triggered were small, usually with volumes of 1 m3 or less, reaching the larger volumes up to 500–1000 m3. Data available from these events point out that large landslides, as known in relation with historical earthquakes in Spain, cannot be induced by moderate to low magnitude earthquakes. Besides, slope morphology seems to control the location of induced instabilities. Thus, when the terrain is steep, as in the area affected by the earthquake in Lorca (2011, Mw 5.1), most of instabilities occur in natural slopes and affect the upper part of slopes. As the relief is less rugged, natural slopes instabilities are progressively less frequent until the extreme case of the 2015 event, when instabilities were located mostly on slopes of the road network.

A superbly exposed ∼5 km 2 slump is developed in middle Pleistocene lacustrine deposits of the Tecopa Basin (California, United States). A subhorizontal detachment (

A database of seismically-induced landslides in the Betic Cordillera is presented. Data included were classified according to landslide typology. Most of them (≈80%) correspond to small size, disrupted landslides (including rock/earth falls and earth slides that disorganize as mass-movement progresses) and the remaining consist mainly of coherent landslides (slumps in soils and rock-slides). Deep seated induced landslides are uncommon in the study zone and have occurred only after the few events of large magnitude reported in the Cordillera. Data available show that events of small magnitude (Mw 10 km) when compared with available upper bound curves for maximum epicentral distances for seismic induced landslides, that concentrate along areas prone to landsliding, like river banks or slopes on soft materials, which points out the importance of the role of slope susceptibility on the occurrence of instabilities during earthquakes. Landslides in the database are then analyzed and a power-law relationship that relates earthquake size, measured as epicentral intensity (Io), to maximum distance of induced landslide valid for the study zone is proposed. Although included data represent a clear partial and incomplete dataset, they show the landslide state of knowledge for this region.

The northern slope of the Sierra de Aitana (Eastern Betic Cordillera) is characterized by a long mountain front with a prominent Eocene limestone scarp overlying ductile Eocene marlstones. This stratigraphic feature and the highly stepped topography produced by several normal faults favor gravitational processes such as rock avalanches, rock slides and rock falls. This paper reports a compound landslide comprising a rotational rock slide and slab-type lateral spreading affecting these materials with blocks of volumes up to 106 m3. This lateral spread process produced singular and spectacular morphological features, the Simas de Partagat, which are trenches 20 m wide and up to 40 m deep, formed by the widening of discontinuities. The use of a differential SAR interferometry technique for monitoring this landslide over a time span of 11 yr has revealed that velocity of movement is insignificant, with rates comprised between 0 and 2 mm yr−1 and cumulative negligible displacements. Individual rock blocks initially located at the free face of the scarp were affected by slides at the base of the scarp, descending from a few to several dozen meters along the slope. Blocks broke up as displacement progresses, with several in different stages of evolution being recognizable along the slope. Differential SAR interferometry shows a greater activity in the area north of compound landslide, although velocity is extremely low (below 16 mm yr−1). This extremely slow movement revealed by interferometry is in agreement with other geological and geomorphological evidence such as the existence of speleothems and cemented breccias against the head walls of the trenches. Both deposits are indicative of a long period of discontinuity widening. Also, undisturbed debris deposits covering ancient rock slides are indicative of very slow gravitational processes characterized by long dormant periods. In addition, a historical picture from 1898 shows nearly negligible change in the Simas de Partagat over this 112 yr period.

Well-exposed soft-sediment deformation (SSD) structures occur in Tecopa paleolake beds largely composed of ash from the Bishop (760 kyr) and the Lava Creek (640 kyr) ultra-plinian eruptions. In both cases the SSD structures affected volcaniclastic deposits concentrated by overland flow from the surrounding topography into the lower slope and lake environments. Re-sedimentation of ash produced alternations of volcaniclastic layers with different grain sizes and ash content that allowed for reverse density gradients, which favoured liquefaction and deformation. In the Tecopa Basin, extensive outcrops show these deformed strata continuing laterally for hundreds of metres, along with three-dimensional exposures. This study illustrates the 3-D complexity of soft-sediment deformation including some novel morphologic features. Of particular interest were examples of superposed deformed beds that laterally change into one single deformed horizon. Heterogeneities in ash concentration, grain-size, and water content produced contrasting permeabilities that were barriers to liquefaction and soft-sediment deformation. The probable causes for liquefaction were Middle Pleistocene paleo-earthquakes. There are several active faults in the region with enough seismic potential to produce moderate to large earthquakes. The fact that a single deformed deposit laterally merges into multiple superposed deformed beds indicates that multilayer liquefaction could be produced by a single shaking event. In these cases, SSD layers are insufficient and unreliable indicators of paleo-seismic recurrence intervals.

Terra Nova, 22, 172–179, 2010 Abstract Giant load-type seismites, uncommon in the geological record, are described in Plio-Pleistocene lacustrine deposits of the Baza Basin (Betic Cordillera, S Iberia). Deformed beds of the marginal lacustrine and distal alluvial facies of the Baza palaeo-lake can be traced continuously for several kilometres. Soft-sediment deformation is represented by load-type structures of large dimensions (pillows around 4 m in width and 2 m in height). Three-dimensional exposures show ellipsoidal pillows separated by fluidized channels without any preferred orientation. The final size of these load-type seismites is strongly influenced by sedimentary factors such as the presence of a reverse density gradient in sediments and the bed thickness. The giant seismites of the Baza basin are located in a region, which is unlikely to have been subjected to high magnitude earthquakes (maximum around 7.0). Therefore, magnitude is not the main factor that controls the size of these load-type structures.

The Ossa de Montiel (2015/02/23, Mw 4.7) earthquake struck the central part of Spain and was felt far from the epicenter (> 300 km). Even though ground shaking was slight (Imax = V, EMS-98 scale), the earthquake triggered many small rock falls, most at distances of 20–30 km from the epicenter, greater than previously recorded in S Spain (16 km) for earthquakes of similar magnitudes. The comparative analysis of available data for this event with records from other quakes of the Betic cordillera (S and SE Spain) seems to indicate a slower pattern of ground-motion attenuation in central Spain. This could explain why slope instabilities occurred at larger distances. Instability was more frequent, and occurred at larger distances, in road cuts than in natural slopes, implying that such slope types are highly susceptible to seismically induced landslides. This work has been funded by Spanish Ministry of Economy and Competitiveness, research project CGL2011-30153-C02-02, and by the research groups RNM-374 (Junta de Andalucía), TECTAC (UCM-910368) and VIGROB-184 (Universidad de Alicante). Mr. Loffredo acknowledges funding of the Università di Roma — La Sapienza (post-graduate grant) (Concorso A N.480 - Area CUN 04).

Tectonic units of the Sierra Espuña-Mula area are described in order to characterize the palaeogeographic passage from the Alpujarride to the Malaguide Complexes through the “intermediate units”. Moreover, the Meso-Cenozoic cover of the Malaguide units in this area show the transition from the Malaguide to the “Internal Dorsal”. Both features are relevant for the palaeogeographic reconstruction and geodynamic evolution of the Betic-Rif Internal Zone (BRIZ) in the framework of the Alpine Perimediterranean Chains. These data, together with others from other sectors of the Betic-Rif Cordillera enable us to propose a palaeogeography during the Triassic rifting with two subsident areas related to two oceanic branches (the Nevadofilabride-Alpujarride to the north, and the Maghrebian, to the south) separated by a continent or shallow marine area (the Malaguide). These branches were closed during post-rifting geodynamic evolution including two different piling phases: a first top-to-the-north in the northern branch (Alpine tectogenesis, Latest Cretaceous-Middle Oligocene); a second top-to-the-south in the southern branch (Maghrebian tectogenesis, Late Oligocene-Early Miocene). The opposite arrangement of units in the Betic with respect to the Rif required clockwise rotations to form the Gibraltar Arc, confirmed by data from the literature. These rotations are related to the westward displacement and subsequent collision of the BRIZ against the African and Iberian palaeomargins.

The Bajo Segura Fault Zone, located at the NE end of the Eastern Betic Shear Zone, has been the site of some of the most intense seismic activity on the Iberian Peninsula in the historical and instrumental time periods. This structure is an active blind fault that does not show any surface rupture. It is characterised by a set of ENE-WSW trending blind thrust faults that offset the Triassic basement and cause active folding of the Upper Miocene-Quaternary sedimentary cover. The main active structures of this fault zone are two ENE-WSW striking reverse blind faults, the Torremendo and the Bajo Segura Faults, and several secondary NW-SE striking dextral faults (San Miguel de Salinas, Torrevieja and Guardamar Faults). These structures continue offshore to the east. From geological, geomorphological and geodetic data, we obtain fault slip rates between 0.2 and 0.4 mm/yr, whereas other authors have proposed higher values ranging between 0.75 and 1 mm/yr. The fault zone can generate earthquakes with maximum estimated magnitudes (Mw) from 6.6 to 7.1 and has approximate recurrence intervals between 4.500 and 21.500 years, Departamento de Ciencias de la Tierra y del Medio Ambiente, Universidad de Alicante, España, Unitat de Tecnologia Marina, Centre Mediterrani d’Investigacions Marines i Ambientals, España, Departamento de Ingeniería Cartográfica, Geodésica y Fotogrametría, Universidad de Jaén, España, Instituto Geológico y Minero de España, España, Departamento de Geología, Universidad de Jaén, España

The Granada and Guadix-Baza Basins, the largest Neogene-Quaternary intramontane basins of the Betic Cordillera (southern Spain), undergo active deformation with an associated moderate level of seismic activity. This deformation is controlled by a NNWSSE compressive regime and an approximate orthogonal tensional regime. The compression produced N70ºE to E-W folds of several scales, the Sierra Nevada antiform being the largest one. The tension is accommodated mainly by NW-SE active normal faults, the most notable being the Baza Fault, in the Guadix-Baza Basin, and the Granada, Sierra Elvira-Dílar and Padul-Dúrcal Faults, in the Granada Basin. In addition, other active faults with different orientations also exist, such as the Alfahuara-Botardo and the Galera faults in the Guadix-Baza Basin, and the Huenes, Obéilar-Pinos Puente and N of Sierra Tejeda Faults in the Granada Basin. Moreover, in several sectors, the presence of orthogonal normal fault sets suggests alternating trends or even radial extension. Slip rates of these active faults, based on geologic markers, vary between 0.06 and 0.5 mm/year. Estimates for the maximum expected magnitude of earthquakes caused by these faults vary between MW 6.0 and 7.0. The N of Sierra Tejeda and the Baza Faults, the largest faults in the Granada and Guadix-Baza Basins, respectively, have the greatest seismic potential. They could cause events up to a magnitude of MW 6.5-7.0, although their reference earthquakes, computed for a return period of 475 years, are on the order of MW 5.0-5.5. Las Cuencas de Granada y Guadix-Baza, las mayores cuencas intramontañosas del Neógeno y Cuaternario de la Cordillera Bética (sur de España), experimentan una deformación activa y tienen asociada una actividad sísmica moderada. La deformación está controlada por una compresión NNO-SSE y una tensión aproximadamente perpendicular. La compresión ha formado pliegues de dirección N70ºE a E-O de muy diferentes tamaños, siendo el antiforme de Sierra Nevada el mayor. La tensión se acomoda sobre todo por fallas normales NO-SE, siendo las más notables de ellas la falla de Baza, en la cuenca de Guadix-Baza, y las de Granada, Sierra Elvira-Dílar y Padul-Dúrcal, en la cuenca de Granada. Además, existen otras fallas activas con diferentes orientaciones, tales como la de Alfahuara-Botardo y la de Galera en la cuenca de Guadix-Baza y las de Huenes, Obéilar-Pinos Puente y norte de Sierra Tejeda en la cuenca de Granada. Además, en varios sectores, la presencia de juegos de fallas ortogonales sugiere cambios en el elipsoide de esfuerzos e incluso una extensión radial. Las tasas de desplazamiento de estas fallas activas, calculadas a partir de marcadores geológicos, varían entre 0,06 y 0,5 mm/año. La estimación del potencial sísmico indica que la máxima magnitud esperable de los terremotos producidos por estas fallas varía entre MW 6,0 y 7,0. La falla del N de Sierra Tejeda y la de Baza, las mayores respectivamente en las Cuencas de Granada y Guadix-Baza, tienen el mayor potencial sísmico. Podrían causar eventos con magnitudes del orden de MW 6,5-7,0, aunque sus terremotos de referencia para un periodo de retorno de 475 años son del orden de MW 5,0-5,5. This work has been financed through projects TOPO-IBERIA CONSOLIDER-INGENIO (CSD2006-00041), CGL2010-21048, CGL-2011-29920, CGL2011-30153-C02-02, P09-RNM-5388 and the Junta de Andalucía groups RNM 370, RNM148 and RNM325.

The most recent tectonic structures of the central-eastern Internal Zones of the Betic Cordillera (from 3.1ºW to 1.7ºW and to the south of 37.525ºN) include fault and folds developed from the Late Miocene onwards, which are related to N-S/NW-SE directed continental collision and moderate thickening of a crust that is relatively hot at depth. In this setting, E-W to WSW-ENE folds, with locally associated E-W transpressive right-lateral and reverse faults, favoured the emersion of the northern Alborán basin palaeomargin and the progressive intramontane basin disconnection. The NNE-SSW to NE-SW trending regional left-lateral Palomares and Carboneras fault zones are dominant structures in the easternmost part of the cordillera. In addition, NW-SE to WNW-ESE trending normal and oblique-slip normal faults are widespread. The collision is still active and continues to drive active folds and faults, some probably being the likely source of moderate-sized earthquakes. The Campo de Dalías and surrounding sectors, deformed by active ENE-WSW folds and NW-SE to WNW-ESE oblique-slip normal faults, are probably the sites with the largest concentration of significant earthquakes during recent years. Moderate-magnitude earthquakes (Mw 5.0 to 6.5) have occurred there at fairly regular intervals, in 1804, 1910 and 1994. Toward the east, NW-SE trending normal faults extending from Almería to the Tabernas basin deform the Quaternary rocks with associated moderate seismicity (the 2002 Gergal Mw 4.7 earthquake, and possibly the 1894 Nacimiento earthquake, felt with intensity VII). In the Sorbas-Vera basin, the Palomares fault zone is also responsible for moderate-sized earthquakes (1518 Vera earthquake). In the Almanzora corridor, NW-SE to WNW-ESE trending Lúcar-Somontín faults also could be considered one of the possible source of moderate-magnitude seismicity (1932 Lúcar, Mw 4.8 earthquake felt with intensity VIII). Toward the east, between Albox and Partaloa, several small reverse faults and associated compressive structures deform Quaternary alluvial and fluvial sediments. Although some of these folds reveal a slow and progressive deformation from the Middle Pleistocene onwards, some of these reverse fault segments that deform the western Huércal-Overa basin could host the 1972 NW Partaloa, mbLg 4.8 earthquake, felt with intensity VII., Instituto Geológico y Minero de España, España, Departamento de Geodinámica, Universidad de Granada, España, Instituto Andaluz de Ciencias de la Tierra, Consejo Superior de Investigaciones Científicas, España, Instituto Andaluz de Ciencias de la Tierra, Universidad de Granada, España, Departamento de Geología, Universidad de Jaén, España, Departamento de Física, Universidad de Jaén, España

The Campo de Dalias is an area with relevant seismicity associated to the active tectonic deformations of the southern boundary of the Betic Cordillera. A non-permanent GPS network was installed to monitor, for the first time, the fault- and fold-related activity. In addition, two high precision levelling profiles were measured twice over a one-year period across the Balanegra Fault, one of the most active faults recognized in the area. The absence of significant movement of the main fault surface suggests seismogenic behaviour. The possible recurrence interval may be between 100 and 300 y. The repetitive GPS and high precision levelling monitoring of the fault surface during a long time period may help us to determine future fault behaviour with regard to the existence (or not) of a creep component, the accumulation of elastic deformation before faulting, and implications of the fold-fault relationship.

13 páginas, 8 figuras., In the Guadix-Baza Basin (Betic Cordillera) lies the Baza Fault, a structure that will be described for the first time in this paper. Eight gravity profiles and a seismic reflection profile, coupled with surface studies, indicate the existence of a NE-dipping normal fault with a variable strike with N-S and NW-SE segments. This 37-km long fault divides the basin into two sectors: Guadix to the West and Baza to the East. Since the Late Miocene, the activity of this fault has created a half-graben in its hanging wall. The seismic reflection profile shows that the fill of this 2,000–3,000 m thick asymmetric basin is syntectonic. The fault has associated seismicity, the most important of which is the 1531 Baza earthquake. Since the Late Tortonian to the present, i.e. over approximately the last 8 million years, extension rates obtained vary between 0.12 and 0.33 mm/year for the Baza Fault, being one of the major active normal faults to accommodate the current ENE–WSW extension produced in the central Betic Cordillera. The existence of this fault and other normal faults in the central Betic Cordillera enhanced the extension in the upper crust from the Late Miocene to the present in this regional compressive setting., This study was partly financed by Projects BTE2001-5230-E, CGL200401636/BTE, CGL2006-06001, CSD2006- 00041 and by the Generalitat Valenciana (GRUPOS03/085, OCYT).

18 pages, 13 figures, 1 table., The present work investigates a mountain front within the Plio-Quaternary deposits belonging to the sedimentary fill of the Guadix-Baza Basin (Betic Cordillera, Southern Spain). This 30 km-long front, developed in soft sediments and within a context of high erosion, is generated by the recent activity of the Baza Normal Fault. The mountain front is the natural limit between the western and eastern sectors, corresponding to the two sub-basins of Guadix and Baza. The two main glacis described in previous works in the area of the Baza Fault – the Old Glacis in the Guadix Sub-basin and the Recent Glacis in the Baza Sub-basin – are interpreted here as a single one, displaced by the fault. Using this Glacis as a marker we deduced that its age and the transition of the basin from endorheic to exorheic must be much older than previous estimations. The Baza Fault may be considered as one of the most active faults of the central part of the Betic Cordillera, according to the results of the general quantitative analysis of the mountain front relief using the Smf/Vf ratio and the SL index., This study was financed by Projects BTE2001-5230-E, CGL2004-01636, CGL2004-03333/BTE, CGL2006-06001 and CSD00041 and Groups 217, 325 and 327 of the Junta de Andalucía.

In this work, we present a detailed analysis of brittle and brittle-ductile structures related to the contacts of a stack of tectonic units cropping out in the Sierra Espufta (Betic Cordillera, southern Spain). These data show two superposition stages with opposing transport directions: first, a top-to-the-north (according to current coordinates) stage (Oligocene in age), and a second stage from the Middle Oligocene-Aquitanian, with a top-to-the-north sense of transport. In the Burdigalian, the Internal Betic Zone units of the Sierra Espuna sector could rotate near 180° because of the oblique collision against the External Zones, and therefore the previous stacking directions went in the contrary direction with respect to that measured nowadays. The reconstruction of movements shows that the Malaguide Complex was situated to the south of the Alpujarride prior to the Alpine tectonics, which is in good agreement with previous

7 pages, 4 figures., The Cabo Cope Unit, which outcrops east of Aguilas (Murcia), belongs to the Maláguide tectonic Complex (Betic Internal Zone) and displays stratigraphic characteristics of particular interest, including Triassic bioclastic carbonate beds which are not common in the Maláguide units. Biostratigrafic fossils have been found in these beds and may correlate with Triassic alpine biofacies. Alpine fauna fossils only appeared in those palaeogeographic units of the Internal Zone of the Cordillera referred to as Alpujárride units, while the influence of the Sephardic faunal province is evident in almost all the cordillera. For these reasons it is noteworthy that new alpine fauna fossils have been found in an Internal Zone unit in which relevant fossils rarely appear. The Triassic succession of the unit studied in this paper can be subdivided into two members: a lower one, which is clastic and contains thick gypsum beds, and an upper one, consisting of carbonate rocks. The lower member has been interpreted as a fluvial-coastal deposit. The upper member is interpreted as a sequence of carbonate ramp deposits. This ramp evolved into a shallow platform with tidal flats typical of a coastal zone. The bivalve fossilsDaonella cf.lommeli (Wissmann) and “Posidonia” sp. have been found in the carbonate member, along with the conodontSephardiella mungoensis (Diebel). These fossils are of the Late Ladinian age and have been found only in this outcroup of the Betic Cordillera. The presence of this fossil assemblage, which belongs to the alpine faunal province, indicates a connection during the Late Ladinian between the Tethys sea and this area of the Maláguide palaeogeographic domain. The palaeogeographic location of the Cabo Cope Unit during the Middle Triassic was at the south-easternmost part of the Betic Basin, implying that the connection between the Tethys and the Betic Basin was established in the easternmost domains of the basin., The authors would like to thank Dra. N. Sold de Porta, of the University of Barcelona, lbr her assistance with the palynological analysis and P. Plasencia, of the University of Valencia, for the conodont investigation. This investigation was carried out within the Junta de Andalucia Research Group RNM 0163 and was apart of Projects PB97-1201 and PB 98-0488 of the DGESIC, Ministerio de Educaci6n y Cultura, Spain.

Summary Faults are rarely a discrete two-dimensional surface, but a three-dimensional volume with a complex internal structure. The structure of a fault zone in 3D is poorly understood, particularly because outcrops exposing fault zones in 3D are rare, and few have large (e.g. 100 m) throw. Detailed 3D studies of fault zones can help provide insight into their internal structure, and processes undergone during faulting as well as improve the predictability of subsurface (e.g. reservoir) models. The main objective of this project is to construct a 3D structural model of a strand of the Baza fault, an active normal fault located in south central Spain in the Betic Cordillera. This strand has an estimated throw of 30 m in relatively unconsolidated clay to silt and carbonates Pliocene sequence. Through a trenching study, 8 vertical dip sections, 3 vertical strike sections and 1 depth section in an area of approximately 80 mA2 were excavated, cleaned, LiDAR scanned, photographed and documented. Based on these sections, we have reconstructed the 3D geometry and associated structures of this superb fault zone. These data can also be useful for geophysical and reservoir modeling studies