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

Masana, Eulàlia ^[1] ; Moreno, X. ^[1] ; Gràcia, E. ^[2] ; Pallàs i Serra, Raimon ^[1] ; Ortuño, M. ^[1] ; López, R. ^[1] ; Gómez-Novell, O. ^[1] ; Ruana, P. ^[3] ; Perea, H. ^[2] ; Stepancikova, P. ^[4] ; Khazaradze, Giorgi ^[3]
1. [1] Universitat de Barcelona
  
  Universitat de Barcelona
  
  Barcelona, España
2. [2] Instituto de Ciencias del Mar
  
  Instituto de Ciencias del Mar
  
  Barcelona, España
3. [3] Universidad de Granada
  
  Universidad de Granada
  
  Granada, España
4. [4] Institute of Rock Structure and Mechanics
  
  Institute of Rock Structure and Mechanics
  
  Chequia
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Localización: Geologica acta: an international earth science journal, ISSN 1695-6133, Vol. 16, Nº. Extra 4, 2018 (Ejemplar dedicado a: . Special Issue: a tribute to Pere Santanach.), págs. 461-476
Idioma: catalán
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Resumen
- 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 CarbonerasFault 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.