Earthquakes distribution and their focal mechanism in correlation with the active tectonic zones of Romania

Abstract

On the basis of an earthquake catalogue covering the time interval from 1929 to 1997 and comprising fault plane solutions, we analyze the distribution of the seismic activity on the Romanian territory in connection with the seismogenic zones, previously defined, and available geological and tectonic information. At the same time, the stress field characteristics, deduced from the available fault plane solutions, are investigated for different depth intervals. Predominant clusterings of the principal deformation axes and rupture plane orientation are observed in the Vrancea subcrustal domain in contrast with the earthquakes in the crust, which show no clear trending in the stress field. A number of 526 events occurred in the period 1929–1997 and having the magnitude 1.5< M S <7.4 are analyzed according to their fault plane solutions. The relatively large number of events provides important and reliable information to redefine from seismological point of view the limits of the seismogenic and active zones.