Reicherter, K., Becker-Heidmann, P. (2008): Tsunami deposits in the western Mediterranean: the remains of the 1522 Almera earthquake. – In: Ubertini, L., Manciola, P., Casadei, S., Grimaldi, S. (Hg.): Earth: Our changing planet, S. JSS002-1791. Umbria Scientific Meeting Association, Perugia, Italy
The 1522 Almería earthquake (M > 6.5) affected large areas in the western Mediterranean and caused more than 2000 causalities. Different epicentral areas have been suspected, mainly along the 50 km long sinistral Carboneras Fault Zone (CFZ), however no on-shore surface ruptures and paleoseismological evidences for this event have been found. High-resolution sea floor imaging (narrow beam sediment profiler) yields evidence for an offshore rupture along a strand of the CFZ that is supported by evaluation of historic documents. Based on these data, a new epicentral area precisely at the observed sea floor rupture area is proposed at N 36 42, W 2 23 in the Gulf of Almería. Drilling in lagunas and salinas of the Cabo de Gata area proved sedimentary evidence for paleo-tsunamis along the Spanish Mediterranean coast. Several coarse grained intervals with fining-up and thinning-up sequences, rip-off clasts, broken shells of lamellibranchs and foraminifera show erosive bases. The coarse-grained intervals show up to three sequences divided from the next one by a small clayey layer. These intervals are interpreted as a tsunami trail and correspond to three individual waves. We have also found multiple intercalations of those tsunamites downhole, which is interpreted as either an expression of repeated earthquake activity or tsunami-like waves induced by submarine slides triggered seismic shaking in the Gulf of Almería. The coast of southern Spain, the Costa de Sol, is one of the touristic hot spots in the Mediterranean Europe and very densely populated. Hence, the impact on the vulnerability is of great concern for society and economy, considering destructive earthquakes in coastal residential and industrial areas, especially a holiday and recreation area in the western Mediterranean region. Our evidence suggests a certain tsunami potential and hazard for offshore active and seismogenic faults in the western Mediterranean region.