Seismic ground motion estimates for the M6.1 earthquake of July 26, 1963 at Skopje, Republic of Macedonia

Abstract

The identification and characterization of active faults as earthquake sources are essential parts of seismic hazard assessment studies. In the area struck by the 1963 Skopje (M = 6.1) earthquake, we define an input fault model according to the proposed source mechanism, the magnitude, and the aftershocks distribution. We test different position for the nucleation point along the fault and we calculate maximum horizontal velocities for a maximum frequency content of 1 Hz. We compare the velocity field with the reported macroseismic intensity one in order to select the fault model that fits the observations best. Our results are in agreement with a seismic source modelled as a 15 × 8 km rectangular plane with magnitude equal to 5.9.