Spatial Distribution of Source Locations of Earth-origin Electromagnetic Pulses Excited before Earthquakes

Abstract

In order to find a possibility of earth-origin electromagnetic (EM) pulses as a precursor of earthquakes, we attempted to obtain spatial distributions of source locations of many EM pulses detected two days before earthquakes. In this paper, we first introduce the procedure for obtaining their source locations, which consists of determinations of exact arrival directions of the EM pulses, estimations of their propagation distances and identifications of their source locations. In deriving a spatial distribution of their locations, we found that the EM pulse sources had been drifting during the period of about 6 hours. The area of the spatial distribution of their source locations was rather small but far from the earthquake epicenter. The spatial difference between the EM pulse source locations and the earthquake epicenter is discussed from view points of conditions for excitations and propagations of EM pulses.

Recent Progress and State of the Art of Seismo-Electromagnetics

“…The microwave antenna onboard AQUA satellite detected microwave emissions (7) , and they also evaluated the posibility of generation of these signals in the laboratory experiment. VLF signals might have been also captured in an antenna installed 100 m deep borehole associated with the 2004 Off Kii Peninsula earthquake (8) .…”

Method of Pointing Source Locations of Earth-origin Electromagnetic Pulses as a Precursor of Earthquakes

“…Based on the successful identification of the source location of the earth-origin EM pulse, we conducted a quantitative analysis of many EM pulses detected on two days before a big earthquake occurred at off-shore of Kii-peninsula at 19:07 JST September 5, 2004, for obtaining spatial distribution of their source locations (5) . Although we obtained some concentrated distributions of source locations by the analysis, the relation between the detected EM pulses and active movements of earth crust remains uncertain.…”