Regional Magnitude Mwa in the Russian Far East

Abstract

The Yuzhno-Sakhalinsk Seismological Regional Information Processing Center (RIPC) recently used the Richter magnitude M_wa to estimate the energy level of Far Eastern earthquakes. To date, this is the most common energy characteristic in the operational catalog of the RIPC. The basis is digital waveforms of regional seismic stations emulated to the characteristics of the Wood–Anderson seismograph. In the present paper, the results of determining the magnitude M_wa in Russian Far Eastern conditions are analyzed. The magnitude determination accuracy is estimated, and station corrections are obtained. The regression relation M_wa and Japanese Meteorological Agency magnitude M_j showed a high similarity between these scales. This made it possible to use M_j as the reference when studying the features of M_wa. The regional seismic network makes it possible to correctly estimate the magnitude M_wa at a regional distance (up to about 1000 km), including for deep-focus earthquakes (up to 600 km). Transfer relations between M_wa and other mass-determined regional energy characteristics of earthquakes are obtained. The M_wa scale can be used to estimate the energy level of any earthquakes in the Kuril–Okhotsk and Sakhalin regions in the magnitude range of weak and moderately strong events and is recommended for inclusion in regional earthquake catalogs for the Russian Far East.