RU4.02TaskB: Source parameters of significant italian historical earthquakes within the SISMOS project framework

Abstract

We have analyzed 18 out of the selected 19 events of the Italian seismic history. We have paid particular attention to the Adriatic coast earthquakes, 1908 Calabro Messinese and the 1917 Sansepolcro earthquakes. The historical bulletins, the instrumental parameters and the paper seismograms for all the 13 events have been recovered. The relocation of the events for which we have the complete set of data (the P and S arrival times and the paper records to read the missing arrival times) was carried out. We have vectorialized seismograms for the recovered components of the following earthquakes: Calabria 1905, Calabro Messinese 1908, Monterchi-Citerna 1917, Senigallia 1930, Adriatic reagion1934,1938, 1962. For the earthquakes occurred during war periods, is very difficult to find the bulletins, the paper seismograms and the instrument parameters. However, for the 1916 Adriatic earthquake we have enough bulletins to estimate the instrumental location. The Sismos team has developed a new methodology to compute the moment tensor. This method has the advantage to be suitable for historical dataset, but require long time computation even using the new multi-dualcore computers. Using this technique we have calculated the moment tensor and magnitude for the 1917 San Sepolcro earthquake using amplitudes from digitized seismograms, while polarities come from both bulletins and seismograms reading.