Update of the European-Mediterranean Regional Centroid Moment Tensor (RCMT) Catalog: an Insight on Notable Recent Mediterranean Seismicity

The European-Mediterranean Regional Centroid Moment Tensor (RCMT) Catalog collects solutions routinely computed since 1997 for earthquakes with moderate magnitude (4.5≤ M ≤ 5.5) in the Mediterranean region. The database represents an extension to smaller magnitudes of the Harvard global CMT catalog, based on analysis of seismograms recorded at regional distance, and modeling of intermediate period surface waves. The catalog, updated to 2005, includes about 650 events, and represents a valuable tool for seismotectonic and geodynamic studies. The most interesting seismic sequences in the most recent years occurred in Northern Africa (Boumerdes, Algerian coast in 2003 and Al Hoceima, Morocco in 2004) and in the Southern Greece, Dodecanese area and Aegean Sea (August 2003 and 2004, October 2005). For most of the events of these sequences moment tensor solutions were not available in the literature. We further extended the catalog back in time for the Italian region, as far as allowed by availability of digital data --- i.e. since 1977 --- with the same analysis and inversion method used for current seismicity. The new dataset includes events in many seismic zones where moderate seismicity had previously been scarcely documented, e.g. the Po Plain and the Adriatic Sea. In particular, both older and more recent seismicity in the Central Adriatic Sea holds particular interest, as the region had often been depicted as aseismic. New solutions, providing new information on the geometry of seismic deformation, mainly represent moderate magnitude events, that can effectively be modeled by the method we use.