For long time people studied only point solution because they were restricted by computer
equipment and low number of high-quality broadband seismographs. Fifteen years
ago, Kikuchi and Kanamori (1991), see also references in that paper, started with multiple
point solutions from teleseismic data. They applied this method for events in Japan
and many other regions. Their code is freely available. In this study we used a similar
method for regional data (completely new code ISOLA - ISOLated Asperities) written by
Zahradn´ık (2005b) - i.e. waveform inversion from regional data based on iterative deconvolution.
For some events, automatic (unconstrained) inversions produce a high non-DC
component, which may be not realistic for typical tectonic earthquakes. In this work we
try to explain events with high non-DC component as multiple events because two separate
events with mechanism near to pure shear can together give mechanism with a high
non-DC component. Our studied region (western Greece) belongs to the most seismically
active part of Europe. The region is widely studied by many seismologists worldwide. A
European collaborative project is focused on the Gulf of Corinth and this thesis has been
partly related to it through the ISOLA package (project 3HAZ coordinated P. Bernard).
Two from three earthquakes studied in this thesis were previously investigated by other
authors, using different methods (Benetatos, 2004; Roumelioti, 2005).