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In the NW of Sierra Tejeda (Spain) it is possible differentiate only two Alpujarride tectonic units, i.e. the Almijara and, in an upper position, the Robledal unit, simplifying previous divisions. Hydrogeological data support this interpretation since a hydraulic connection exists between the two areas occupied by marbles (Sierra Tejeda and Rodaderos sectors). Both areas has been previously considered as belonging to two different tectonic units not directly connected. In the Robledal unit, gneisses in the lower part of the lithologic sequence correlate with other units of the Guajares-Jubrique/Los Reales group (upper group of Alpujarride units). Extensional deformations are superposed over these tectonic units, but, according to field observations, they have not the enormous importance attributed to them in previous models, as they do not differentiate new tectonic units, at least in this area. New E-W faults are drawn along the northern edge of Sierra Tejeda, contributing to the westward drift of the Betic Internal Zone. ; [ES] Al NO de Sierra Tejeda solo se pueden diferenciar dos unidades tectónicas alpujárrides, la de Almijara y, sobre ella, la de Robledal, simplificando divisiones previas. Datos hidrogeológicos avalan esta interpretación ya que apuntan a la posible conexión hidráulica entre dos áreas ocupadas por mármoles (sectores de Tejeda y Rodaderos) que previamente han sido consideradas como unidades tectónicas diferentes lo que lo hace improbable. En la unidad Robledal la presencia de gneises en la parte inferior de la secuencia litológica permite su correlación con otras unidades del grupo Guájares-Jubrique/ Los Reales (grupo superior de unidades del Complejo Alpujárride). Deformaciones extensionales se superponen al cabalgamiento de unidades, pero a las que no damos la enorme importancia atribuida en previos modelos, pues no permiten, al menos en esta área, la diferenciación de nuevas unidades tectónicas. Se muestran, además, nuevas fallas E-O situadas al N de Sierra Tejeda, que facilitaron el desplazamiento hacia el oeste de la Zona Interna Bética. ; This work is a contribution of the projects DAMAGE (AEI/FEDER CGL2016-80687-R) and CGL2015-65858-R of DGICYT, and the research groups RMN-308 and RMN-370 of Andalusia Regional Government. We thank Professor M. Martín-Martín (Alicante) and an anonymous reviewer whose corrections and suggestions have clearly improved this article

The reactivation of very large landslides may cause severe damage to society. Its prevention and management requires detailed information on the geometry and structure of these landslides, but the use of standard techniques (boreholes) may be prohibitive from an economic point of view. To overcome these difficulties, geophysical techniques are of special interest because they allow for studying very large areas at a reasonable cost. In this paper, we present a case study wherein the analysis of ambient noise allowed us to produce a model of a large landslide near Granada (southern Spain). The geometry and location of the failure zone, as well as the assessment of the state of involved materials, were estimated by combining two available boreholes and different geophysical techniques (downhole tests and the spectral analysis of ambient noise, horizontal to vertical spectral ratios (HVSR) and the frequency-wavenumber (f-k) methods). The results have allowed us to differentiate between values within the landslide mass with respect to those of stable materials, and to perform for the first time a comprehensive geological model of this unstable mass. Differences were also observed within the landslide mass (earth flow vs. slide zones), which are attributed to differences in the degree of alteration and the disturbance of the internal structure of materials constituting the landslide mass. These results show that techniques based on the measurement of ambient noise are of special interest for studying very large, highly remolded landslide masses. ; EU (FEDER), by the Secretaría de Estado de Investigación, Desarrollo e Innovación of the Spanish government (projects CGL2015-65602-R and CGL2016-77688- R) ; Junta de Andalucía (project GGI3002IDIN) ; Programa Operativo FEDER Andalucía 2014–2020 ; Research Groups VIGROB-184 and VIGROB-116 (University of Alicante) ; University of Jaén

13 páginas, 4 figuras, 2 tablas. ; [EN] New biostratigraphic and field data are gathered from the two Oligo-Miocene marine transgressive cover of the Rifian Ghomaride units: i) the latest Oligocene-Aquitanian Fnidek-Ciudad Granada cycle, the top of which is here dated with planktonic foraminifera as latest Aquitanian and ii) the Burdigalian Sidi Abdeslam-Viñuela cycle, for which five outcrops are newly discovered north of the city of Tetuan. These outcrops display pelitic sequences containing siliceous horizons in their upper levels. These levels yielded nannofossil assemblages indicating the middle Burdigalian Sphenolithus belemnos zone. Regionally, both cycles may occur in the same principal depocentres, but undergo significant lateral and vertical change in their stacking pattern. Indeed, while in the central parts of the depocentres the two successive cycles may conformably stack in a near stratigraphic continuity, in the marginal parts an erosional and/or a low-angle angular unconformity may separate them. Far from the main depocentres, the Fnidek and Sidi Abdeslam cycles independently rest on the Paleozoic basement through basal conglomerates, suggesting displacement of the areas of sedimentation in the change of cycle. These tectonically mediated paleogeographic changes culminated with gravitational back-slide processes that resulted in the emplacement of Jbel Zem Zem Numidian massif over the middle Burdigalian marine levels topping the Sidi Abdeslam-Viñuela cycle. This emplacement was initiated by a docking-induced back-thrusting, and subsequently triggered by a post-collision extensional event. A possible Tertiary tectonic scenario for the western front of the Alboran domain is proposed herein. ; [ES] Se aportan nuevos datos bioestratigráficos y de campo de la cobertera oligo-miocena de las unidades gomárides (Zona Interna Rifeña) concernientes: i) al ciclo Oligoceno terminal- Aquitaniense de las formaciones Fnidek-Ciudad Granada, cuya parte superior se ha datado en este trabajo con foraminíferos planctónicos como Aquitaniense terminal, y ii) al ciclo Burdigaliense de las formaciones Sidi Abdeslam-Viñuela, del cual se han descubierto cinco nuevos afloramientos situados al norte de Tetuán. Estos afloramientos presentan secuencias pelíticas que contienen horizontes silíceos intercalados en sus niveles superiores. Estos niveles contienen asociaciones de nannofósiles que datan la zona de Sphenolithus belemnos del Burdigaliense medio. Regionalmente, ambos ciclos pueden observarse en los mismos depocentros principales, aunque se observan importantes cambios laterales y verticales, especialmente en el paso de un ciclo a otro. De hecho, mientras en las partes centrales de los depocentros los dos ciclos pueden superponerse en continuidad estratigráfica, en los márgenes existen discordancias erosivas, a veces también angulares de bajo ángulo separándolos. Lejos de los depocentros principales, los conglomerados basales de uno u otro ciclo descansan independientemente sobre el basamento paleozoico, sugiriendo un desplazamiento de las áreas de sedimentación en el cambio de ciclo. Estos cambios paleogeográficos producidos por causas tectónicas quedaron sellados por los importantes retrocabalgamientos gravitacionales que dieron lugar al emplazamiento del Numídico del Jbel Zem Zem que cubren a los niveles marinos del Burdigaliense medio del techo del ciclo Sidi Abdeslam-Viñuela. Este emplazamiento se inició por el bloqueo del avance de las unidades internas del Rif que indujo los retrocabalgamientos, en parte también provocado por los procesos extensionales que ocurrían al Este, hacia el mar de Alborán. Se propone al respecto un posible escenario tectónico de la evolución terciaria del sector occidental del dominio de Alborán. ; This work was financially supported by «Grupos de Investigación» RNM-146 and RNM-217 and also by project P06-RNM 01521 of the Spanish regional government «Junta de Andalucía». ; Peer reviewed

The reactivation of very large landslides may cause severe damage to society. Its prevention and management requires detailed information on the geometry and structure of these landslides, but the use of standard techniques (boreholes) may be prohibitive from an economic point of view. To overcome these difficulties, geophysical techniques are of special interest because they allow for studying very large areas at a reasonable cost. In this paper, we present a case study wherein the analysis of ambient noise allowed us to produce a model of a large landslide near Granada (southern Spain). The geometry and location of the failure zone, as well as the assessment of the state of involved materials, were estimated by combining two available boreholes and different geophysical techniques (downhole tests and the spectral analysis of ambient noise, horizontal to vertical spectral ratios (HVSR) and the frequency-wavenumber (f-k) methods). The results have allowed us to differentiate between values within the landslide mass with respect to those of stable materials, and to perform for the first time a comprehensive geological model of this unstable mass. Differences were also observed within the landslide mass (earth flow vs. slide zones), which are attributed to differences in the degree of alteration and the disturbance of the internal structure of materials constituting the landslide mass. These results show that techniques based on the measurement of ambient noise are of special interest for studying very large, highly remolded landslide masses ; This study was funded by the EU (FEDER), by the Secretaría de Estado de Investigación, Desarrollo e Innovación of the Spanish government (projects CGL2015-65602-R and CGL2016-77688- R), by the Junta de Andalucía (project GGI3002IDIN), the Programa Operativo FEDER Andalucía 2014-2020-call made by the University of Jaén 2018, and by Research Groups VIGROB-184 and VIGROB-116 (University of Alicante)

The reactivation of very large landslides may cause severe damage to society. Its prevention and management requires detailed information on the geometry and structure of these landslides, but the use of standard techniques (boreholes) may be prohibitive from an economic point of view. To overcome these difficulties, geophysical techniques are of special interest because they allow for studying very large areas at a reasonable cost. In this paper, we present a case study wherein the analysis of ambient noise allowed us to produce a model of a large landslide near Granada (southern Spain). The geometry and location of the failure zone, as well as the assessment of the state of involved materials, were estimated by combining two available boreholes and different geophysical techniques (downhole tests and the spectral analysis of ambient noise, horizontal to vertical spectral ratios (HVSR) and the frequency-wavenumber (f-k) methods). The results have allowed us to differentiate between values within the landslide mass with respect to those of stable materials, and to perform for the first time a comprehensive geological model of this unstable mass. Differences were also observed within the landslide mass (earth flow vs. slide zones), which are attributed to differences in the degree of alteration and the disturbance of the internal structure of materials constituting the landslide mass. These results show that techniques based on the measurement of ambient noise are of special interest for studying very large, highly remolded landslide masses. ; This study was funded by the EU (FEDER), by the Secretaría de Estado de Investigación, Desarrollo e Innovación of the Spanish government (projects CGL2015‐65602‐R and CGL2016‐77688‐R), by the Junta de Andalucía (project GGI3002IDIN), the Programa Operativo FEDER Andalucía 2014–2020—call made by the University of Jaén 2018, and by Research Groups VIGROB‐184 and VIGROB‐116 (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.

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. ; This research was funded by the Spanish Ministry of Science, Innovation and University (Research Projects: RTI2018-100737-B-I00 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).