Studies on the contribution of some geological factors to seismic hazard

Abstract

The present study is primarily meant to make a separation of the amplification effects in the intensity distribution within the macroseismic field function of their different causes, i.e. the activation of some regional tectonic lines during the seismic motion and local seismogeological conditions.With this end in view, the methodology used consists of filtering the direct macroseismic observations by means of the weighted mean-values method and outlining the regional and local field anomalies.The regional anomaly map of the macroseismic field of the 4 March 1977 Vrancea earthquake, including the southern and south-eastern part of the Outer Carpathian Zone, has been analyzed. Some dislocations, located in the platform basement, which functioned as seismic energy amplifiers during the event, have been identified.The results obtained can be used in seismotectonic and microzoning studies.