Paleoseismologic advances in the Granada basin (Betic Cordilleras, southern Spain)

Authors

  • K.R. REICHERTER

Abstract

The Betic Cordilleras in southern Spain have experienced a number of moderate to strong seismic events during the last 2000 years of reported historical earthquakes. These earthquakes are distributed along the southern margin of Spain from Cádiz to Alicante, and offshore in the Alborán sea, reaching the island of Mallorca. Pliocene to Holocene alluvial and colluvial sediments in Neogene basins and adjacent smaller basins in the Betic Cordilleras display a broad range of faults and structures presumably related to coseismic surface deformation. A number of historical earthquakes capable of producing surface ruptures are presented. This study is focussed on reported ruptures and fault scarps, e.g., those of the Christmas event of 1884 (M 6.5-7) near Ventas de Zafarraya, in the southwestern and northeastern parts of the Granada basin. Displaced and buried paleosols and colluvial wedges in the hanging wall suggest multiple fault reactivation. AMS 1 4C-dating indicates at least three strong events along the Ventas de Zafa rr aya fault during the last 9 ka. Activefaults, and hence seismogenic deformation, are distributed in the Betics, which considerably hinders the calculation of recurrence rates of strong earthquakes along discrete faults. The maximum expectable events for the study area are in the order of M 7.

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Published

2001-01-12

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Articles