The 1995 Neftegorsk earthquake: Tomography of the source zone

The Neftegorsk earthquake of May 27, 1995, which was the most destructive e arthquake within the present boundaries of Russia, was studied by the Inter national Epicentral Expedition, which gathered unique data on the surface r upture and on its aftershocks. In the present study, based on these data an d employing the method of local seismic tomography, a 3-D velocity structur e is obtained, and aftershock hypocenters are relocated. It is shown that t he earthquake source (fault plane) does not unambiguously correlate with va riations in the velocity field. However, areas of lower velocities correspo nd to source ends, as was noted in other similar papers. In several cross s ections, the source area correlates with a bench of velocity contours. Over all, the area under study indicates a high degree of velocity inhomogeneity .