THE TECTONIC ENVIRONMENT AND SOURCE PARAMETERS OF THE KHAILINO, KORYAKIYA EARTHQUAKE OF MARCH 8, 1991: DOES A BERINGIA PLATE EXIST?A. V. Lander, B. G. Bukchin, A. V. Kiryushin, and D. V. Droznin
As can be observed from the seismicity of the last decade, a continuous seismic belt bounds the Bering Sea on the west identifying the present-day Beringia plate. We discuss alternative hypotheses on the origin of the South Koryakiya seismicity and test them using data for the largest Koryakiya earthquake. We obtain estimates of earthquake focal mechanism and source spatio-temporal integral parameters from long period surface wave records. We reconstruct seismogenic strain fields from aftershock data and develop a qualitative model of the source time history. We demonstrate a relationship between the source processes and the recent tectonics of South Koryakiya. The present-day evolution of the plate boundary is compared with past tectonic processes in the region. We finally develop a rough model of the Beringia plate motion.