Geometry and kinematics of the Baza Fault (central Betic Cordillera, South Spain)insights into its seismic potential

  1. Medina-Cascales, I.
  2. Martin-Rojas, I.
  3. García-Tortosa, F.J.
  4. Peláez, J.A.
  5. Alfaro, P.
Aldizkaria:
Geologica acta: an international earth science journal

ISSN: 1695-6133

Argitalpen urtea: 2020

Alea: 18

Zenbakia: 1

Mota: Artikulua

DOI: 10.1344/GEOLOGICAACTA2020.18.11 DIALNET GOOGLE SCHOLAR lock_openDialnet editor

Beste argitalpen batzuk: Geologica acta: an international earth science journal

Laburpena

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.

Finantzaketari buruzko informazioa

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. In addition to the authors, Julia Castro were also involved in the field campaign. We thank her for active participation and constructive discussions. We would also like to thank the reviewers Octavi Gómez and José Jesús Martínez Díaz, whose suggestions greatly improved the manuscript. The authors gratefully acknowledge the donation of academic licenses of the software MOVE© by Petroleum Experts (PETREX), which were used to develop the 3D model of the BF.