Istituto Nazionale di Oceanografia e di Geofisica Sperimentale-OGS
Doi
Abstract
The aim of this study is to test the stability of moment tensor solutions for crustal
earthquakes in the Calabro-Peloritan area (southern Italy). We used waveforms
recorded by the Italian National Seismic Network managed by the Istituto
Nazionale di Geofisica e Vulcanologia and the CAT-SCAN (Calabria Apennine
Tyrrhenian - Subduction Collision Accretion Network) project. We computed the
moment tensor solutions using the Cut And Paste (CAP) method. The technique
allows the determination of the source depth, moment magnitude and focal
mechanisms using a grid search technique. For the earthquakes investigated, we
tried different station distributions and different velocity models. Results were also
checked by computing the moment tensor solutions using the SLUMT grid-search
method. Both methods (CAP and SLUMT) allow time shifts between synthetic and
observed data in order to reduce the dependence of the solution on the assumed
velocity model and on earthquake location errors. Comparisons have been made
with the available published solutions. The final focal mechanisms were robustly
determined. We show that the application of the CAP and SLUMT methods can
provide good-quality solutions in a magnitude range not properly represented in the
Italian national earthquake catalogues, and where the solutions estimated from Ponset
polarities are often poorly constrained