Current Status of Observational Studies on Short-Term Earthquake Prediction Research by Using Electromagnetic Phenomena

Abstract

Despite its extreme importance and decades of e#orts, practical short-term earthquake prediction still remains to be achieved in future. However, the electromagnetic research has been demonstrating some promises. This paper briefly reviews the recent progress of what we call "seismo-electromagnetics", mainly referring to Japanese studies by the observational point of view. We demonstrate some results of observations, in varied frequency ranges, on the anomalous telluric current, ULF geomagnetic transient change, VLF-HF natural emissions and anomalous transmission of VLF and VHF band radio waves. We also summarize proposed physical mechanisms of these phenomena, including the notion called "LithosphereAtmosphereIonosphere (LAI) Coupling". We believe that electromagnetic studies will play an important role in not only earthquake prediction but also in understanding physical processes of earthquake generation.