Por Pedro JM Costa (Instituto Dom Luiz - IDL & M-152 research team).

Abstract: Deposits of the AD 1755 tsunami have been well studied along the southern Portuguese coast, but the impact of backwash signature has not been well understood here and elsewhere. The RV Meteor M152 expedition mapped and sampled two transects perpendicular to the south coast of the Algarve, off Portugal, in water depths from 60 to 600 meters. Preliminary results have revealed that, at least, four major events left depositional imprints in the Holocene lithostratigraphic column. These deposits display sharp or erosional contacts, compositional contrast and coarser composition than the under and overlying sediments. They were dated between AD 1755- and 2000-years BC. The work presented here strongly suggests the shallow offshore area as a reliable sedimentary archive for tsunami events with obvious implications for the establishment of generation mechanisms, return periods and hazard.