Estimation of the Efficiency of Combined Characteristics of ULF-ELF Fields as a Precursor to Earthquakes Based on the Observations in February-March 2007 in Moshiri

Abstract

:Earlier measurements at Karymshino observatory (Kamchatka peninsula, Russia) indicated that there appeared electromagnetic radiation in the frequency range of ULF-ELF a few days before earthquakes (EQs). It was shown that its combined characteristics of the ratio of the field components and the dispersion of field ellipticity were most sensitive to this radiation. We have also shown its high efficiency as an EQ precursor. Here we have tried to estimate its reliability by using the data from an induction magnetometer at another observatory Moshiri in Japan. The data of five weeks in February-March 2007 were analyzed and as a result, reliable precursors were found for four most significant EQ events in the vicinity of the observatory.