Caracterización estructural de la falla activa de Galera (Cordillera Bética central, sur de España)

Resumen

From the Late Miocene, the central Betic Cordillera (S Spain) has been subject to a WSW-ENE extension, which has been accommodated by NW-SE normal faults. In addition, faults with different kinematics were also developed in this region. One of these structures is the Galera Fault (GF), a strike-slip fault located near the NE border of the Guadix-Baza basin. This is an active structure with an associated earthquake: the 1964 SW Galera event (mbLg 4.8). Data about this fault are scarce. Knowing the detailed structure of this fault will be the base for future studies related with its palaeoseismological and seis- mogenic characterization, among others. The aim of this work is a detailed structural description of the GF (geometry and kinematics) from surface data. The GF is ca. 30 km, SW-NE striking left-lateral strike-slip fault. On its central sector, the surface expression of the GF consists of a fault zone with a variable width between 500 to 1500 m. The fault zone is formed by a main fault striking N65E wich presents several relay zones. Slickensides show main sinistral kinematics, although the displacement of stratigraphic markers also indicate a vertical throw component. A large number of ~N-S striking secondary faults are also observed. These are low extension structures that branch out northwards from the main fault. Both their slickenlines and stratigraphic markers show normal fault kinematics, with throws ranging from a few meters to tens of meters. Towards the SW, the GF seems to be related to the normal Baza Fault (BF). Present available data indicate that the GF is a transfer fault associated to the BF.