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1 Institute of Neotectonics and Natural Hazards, RWTH Aachen University, Lochnerstr. 4-20, 52056 Aachen, Germany
2 Institut für Bodenkunde, Universität Hamburg, Allende-Platz 2, 20146 Hamburg, Germany
* Corresponding author (e-mail: k.reicherter{at}nug.rwth-aachen.de)
Shallow drilling in the lagoon of the Cabo de Gata area proved sedimentary evidence for a palaeo-tsunami along that part of the Spanish Mediterranean coast. Several coarse-grained intervals form fining-up and thinning-up sequences that are interpreted as tsunamites. Inland-extending sand sheets are used to identify tsunamigenic inundations. Other indicative features found are erosive bases, rip-up clasts, broken shells of bivalves and benthic/planktic foraminifera. The coarse-grained intervals consist of up to three sequences separated from each other by a silty mud drape. These intervals are interpreted as deposits of a tsunami train and correspond to three individual waves. Radiocarbon dating reveals evidence that these layers can be ascribed to deposition during the 1522 Almería earthquake.
The 1522 Almería earthquake (M>6.5) affected large areas in the western Mediterranean and caused more than 1000 casualties. The epicentral area was offshore in the Gulf of Almería (southern Spain) along the Carboneras Fault Zone and seismic shaking triggered submarine slides in the Gulf of Almería, which may have caused tsunami waves.
We have also found another intercalation of tsunamites downhole, which are interpreted as either an expression of repeated earthquake activity or tsunami-like waves induced by submarine slides triggered by seismic shaking in the Gulf of Almería. Our evidence suggests a definite tsunami potential and hazard for offshore active and seismogenic faults in the western Mediterranean region.
