The Carrascoy Fault (CAF) is one of the main active faults that form part of the Eastern Betic Shear Zone, a 450 km fault system that accommodates most of the convergence between the Eurasian (Iberia) and Nubian plates in the Betic Cordillera, south Spain. Although the CAF represents a major earthquake threat to the nearby City of Murcia, studies on its Quaternary tectonics and seismogenic potential are scarce to date. We present evidence that supports the division of the CAF into two overlapping segments with contrasting tectonic structure, Quaternary activity, and landform control: a SW segment, characterized by a broad fold‐and‐thrust zone similar to the forebergs defined in the Gobi‐Altai region, and a NE segment, characterized by a sharp mountain front controlled by strike‐slip tectonics. We attribute the differentiation into these two segments to the stresses associated with topography, which in turn is a consequence of the shortening component, at the middle Pleistocene, after circa 217.4 ka. For the SW segment we infer the occurrence of 9 to 11, M_w 6.7 paleoearthquakes in the last 30.2 kyr, and a slip rate of 0.37 ± 0.08 m/kyr. We date the occurrence of the last surface rupture event after 2750 B.P., and we estimate an average recurrence period of major events of 3.3 ± 0.7 kyr.

El singular contexto geológico de los llanos de La Larri (Parque Nacional de Ordesa-Monte Perdido, Pirineo Oscense) facilitó la formación de un importante complejo sedimentario de carácter yuxtaglaciar durante el último ciclo glaciar en el Pirineo central. En este estudio se ha realizado un análisis conjunto de cartografía geomorfológica, descripción de afloramientos, levantamiento e interpretación de perfiles de tomografía eléctrica y estudio de las principales unidades sedimentarias encontradas en 3 sondeos de hasta 17 m de profundidad. Los resultados han puesto de manifiesto la existencia de un importante paleolago con una potencia superior a 40 m, así como ha permitido definir la geometría del depósito y sus principales unidades. Las dataciones mediante radiocarbono de algunas muestras de superficie y subsuelo permiten afirmar que la sedimentación en el paleolago se inició antes de los 35 ka y finalizó, por la colmatación completa de su cuenca, hace unos 11 ka.

The Los Tollos Fault is a recent and important feature of the Eastern Betic Shear Zone, one of the major tectonic structures in South Iberia accommodating the convergence between Nubian and Eurasian plates in the western Mediterranean. The Los Tollos Fault became active by the end of Middle Pleistocene introducing some paleogeographical modifications. Previously mapped as a secondary normal fault related to the Carrascoy Fault, recent research evidences that the Los Tollos Fault is an independent Holocene active left-lateral reverse fault extending for at least 15 km. Data analysis from 4 trenches dug across the fault has revealed the occurrence of at least two paleo-earthquake events during the Holocene. The most recent event is dated between 2,740 and 2,140 yr BP (8th to 2nd centuries BC). The size of the paleoevents is calculated to be Mw 6.3 – 6.6 following empirical regressions on surface rupture length. The recurrence interval is estimated to be between 2,200-6,860 years, fitting a slip rate for the fault between 0.12 and 0.17 mm/yr. Such parameters highlight the Los Tollos Fault as a tectonic structure with a considerable activity located relatively close to densely populated areas. These seismogenic parameters should be considered in future reassessments of the seismic hazard of the region.