MIGRATION OF SEISMIC ACTIVITY AT THE CASPIAN SEAA.T. Ismail-zadeh
The epicentral migration following great $(M\ge 6)$ earthquakes in the western and central Caspian Sea is examined by the analysis of catalogs of major earthquakes in the period 1930-1990. The analysis indicates the southeast direction of migration of the seismic activity in the region. The average migration velocity is found to be approximately 6 km per year. An attempt is made to predict earthquakes using models of tectonic stress waves created by migration of deformation in the crust and the upper mantle. These stress waves, appearing after large events, can trigger new events in other regions. A mathematical model describing propagation of stress in the lithosphere is studied. Numerical results indicate the variation of the migration velocity with the lithosphere thickness and effective asthenosphere viscosity. That velocity varies from 1 to 100 km per year for reasonable values of the parameters.