First evidence of paleoearthquakes along the Carboneras Fault Zone (SE Iberian Peninsula): Los Trances site

Authors

  • E. MASANA Departament dinàmica de la Terra i de l’oceà, grup RISKNAT, Universitat de Barcelona. Carrer Martí Franquès s/n, 08028 Barcelona, Spain.
  • X. MORENO Departament dinàmica de la Terra i de l’oceà, grup RISKNAT, Universitat de Barcelona. Carrer Martí Franquès s/n, 08028 Barcelona, Spain.
  • E. GRÀCIA B-CSI, Institut de Ciències del mar-CSIC Pg. Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
  • R. PALLÀS Departament dinàmica de la Terra i de l’oceà, grup RISKNAT, Universitat de Barcelona. Carrer Martí Franquès s/n, 08028 Barcelona, Spain.
  • M. ORTUÑO Departament dinàmica de la Terra i de l’oceà, grup RISKNAT, Universitat de Barcelona. Carrer Martí Franquès s/n, 08028 Barcelona, Spain.
  • R. LÓPEZ Departament dinàmica de la Terra i de l’oceà, grup RISKNAT, Universitat de Barcelona. Carrer Martí Franquès s/n, 08028 Barcelona, Spain.
  • O. GÓMEZ-NOVELL Departament dinàmica de la Terra i de l’oceà, grup RISKNAT, Universitat de Barcelona. Carrer Martí Franquès s/n, 08028 Barcelona, Spain.
  • P. RUANO departamento de geodinámica, Facultad de Ciencias, Universidad de Granada. Avenida de la Fuente Nueva s/n, 18071 Granada, Spain. Instituto andaluz de Ciencias de la Tierra (CSIC-UGR). Avenida de la Fuente Nueva s/n, 18071 Granada, Spain.
  • H. PEREA B-CSI, Institut de Ciències del Mar-CSIC Pg. Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain. GRD, Scripps Institution of oceanography - University of California San Diego 8622 Kennel Way, La Jolla, CA 92093, United States.
  • P. STEPANCIKOVA Institute of rock Structure and mechanics, Czech academy of Sciences. V Holesovickach 41, 18209 Prague, Czech Republic.
  • G. KHAZARADZE Departament dinàmica de la Terra i de l’oceà, grup RISKNAT, Universitat de Barcelona. Carrer Martí Franquès s/n, 08028 Barcelona, Spain.

DOI:

https://doi.org/10.1344/GeologicaActa2018.16.4.8

Keywords:

Paleoseismology, Eastern Betics Shear Zone, Carboneras Fault Zone, Seismogenic fault

Abstract

Seismogenic faults that have not produced historical large earthquakes remain unnoticed and, thus, are dangerously left out from seismic hazard analyses. The seismogenic nature of the Carboneras Fault Zone, a left-lateral strikeslip fault in the Eastern Betic Shear Zone (southeastern Spain), has not been fully explored to date in spite of having a morphological expression equivalent to the Alhama de Murcia Fault, a seismogenic fault in the same tectonic system. This study provides the first paleoseismic evidence of the seismogenic nature of the Carboneras Fault Zone, based on the analysis of 3 trenches at Los Trances site, on the northwestern edge of the La Serrata Range. Cross cutting relationships and numerical dating, based on radiocarbon, thermoluminescence and U-series, reveal a minimum of 4 paleoearthquakes: Paleoearthquake1 (the oldest) and Paleoearthquake2 took place after 133ka, Paleoearthquake3 occurred between 83–73ka and Paleoearthquake4 happened after 42.5ka (probably after 30.8ka), resulting in a maximum possible average recurrence of 33ka. This value, based on a minimum amount of paleoearthquakes, is probably overestimated, as it does not scale well with published slip-rates derived from offset channels or GPS geodetical data. The characterization of this fault as seismogenic, implies that it should be considered in the seismic hazard analyses of the SE Iberian Peninsula.

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Published

2018-12-20