Effect of changing Velocity model on the Earthquake focal mechanism solutions in Syria

Abstract

Seismic digital network records were processed in Syria and 50 recorded earthquakes were selected at more than 8 stations between 2009 and 2011 in order to study the effect of the velocity model changes on the seismic focal mechanism solutions, depth and epicenters position. The first velocity model is used at the National Seismological Center [Ibrahim et al., 2009]. However, the second velocity model is obtained depending on reducing the mean non-conformance (RMS) value of a sample of 50 earthquakes. The results showed that the changes in the velocity model had little effect on the location of the earthquake and a significant impact on the depth of the earthquake focus. After calculating the focal mechanism for the two velocity models, it became clear that the change in movement type (focal mechanism type) was weak and 82% of it remained unchanged (normal-reverse-strike slip), while the change in the tendency and direction of the fault plans solutions was significant and change 54 % Of them, which are reliable results for the local network in Syria.