Mass determination of moment magnitudes Mw and establishing the relationship between Mw and M L for moderate and small Kamchatka earthquakes

Abstract

The average relationship is established between the basic magnitude for the Kamchatka regional catalog, M L , and modern moment magnitude Mw. The latter is firmly tied to the value of the source seismic moment M0 which has a direct physical meaning. M L magnitude is not self-reliant but is obtained through the conversion of the traditional Fedotov’s S-wave energy class, K S1,2 F68 . Installation of the digital seismographic network in Kamchatka in 2006–2010 permitted mass estimates of M0 and Mw to be obtained from the regional data. In this paper we outline a number of techniques to estimate M0 for the Kamchatka earthquakes using the waveforms of regional stations, and then compare the obtained Mw estimates with each other and with M L , based on several hundred earthquakes that took place in 2010–2014. On the average, for Mw = 3.0–6.0, Mw = M L –0.40; this relationship allows obtaining Mw estimates (proxy-Mw) for a large part of the regional earthquake catalog with M L = 3.4–6.4 (Mw = 3.0–6.0).