Current status of seismo-electromagnetics for short-term earthquake prediction

Short-term (timescale of hours, days and weeks) earthquake (EQ) prediction is of essential importance to mitigate EQ disasters. Short-term EQ prediction has so far been based on seismic measurements (i.e. mechanical observation of crustal movements), but it was concluded in Japan about 10 years ago that EQ prediction is impossible by means of the mechanical method. Hence, there has been an increased interest and a lot of progress in non-seismic measurement during the last decade. A new approach was developed where electromagnetic measurements provide microscopic information on the lithosphere. The present paper is intended to give a history of short-term EQ prediction, and also we hope that this paper reviews the current status of a new science field, ‘seismo-electromagnetics’. We make a general review of different phenomena taking place in the lithosphere, atmosphere and the ionosphere, but we pay more attention to the subjects of our preference including lithospheric ultra low frequency (ULF) electromagnetic emissions, and seismo-ionospheric perturbations.