Development of newly designed VHF interferometer system for observing earthquake-related atmospheric anomalies

Abstract

Temporal correlation between atmospheric anomalies and earthquakes has recently been veri_ed statistically through measuring VHF FM radio waves transmitted beyond the line-of-sight. In order to locate the sources of such atmospheric anomalies, we developed a VHF interferometer system (bistatic-radar type) capable of Finding the arrival direction of FM radio waves scattered possibly by earthquake-related atmospheric anomalies. In general, frequency modulation of FM radio waves produces ambiguity of arrival direction. However, our system, employing highsampling rates of the order of kHz, can precisely measure the arrival direction of FM radio waves by stacking received signals. © 2009 The Japan Academy.