The determination of earthquake size and source geometry in the Mediterranean Sea

ABSTRACT

The deployment of modern digital seismic networks is changing the seismological practice of estimating the earthquake size and source geometry. Here we discuss applications and limitations of the principal parameters used in quantifying earthquakes magnitude, fault plane solutions and moment tensors. We present a method for the rapid determination of the moment tensor using digital waveforms from a regional network, suitable for application to regional earthquakes (up to 3000 km distance) and to significant global events. The algorithms are routinely applied to significant Mediterranean and global events using digital data recorded by MEDNET; we show results for the largest global earthquakes of 1990 and for 20 significant Mediterranean earthquakes of 1990-1992, including the large shocks in Romania (May 30, 1990), Iran (June 20, 1990), Caucasus (April 29, 1991), Turkey (March 13, 1992) and Egypt (October 12, 1992). The MEDNET results are consistent with focal mechanisms and CMTs derived from global data and local networks, proving that an advanced regional seismic network is capable of providing accurate, rapid control of regional and global seismicity