Short-term electromagnetic precursors of earthquakes

In the study of the relationship between electromagnetic and seismotectonic processes, we analyzed the data of three observatories located at large distances, considering both latitudes and longitudes, and detected electromagnetic impulses in the frequency range from 0 to 5 Hz, which were recorded minutes before earthquakes. Detailed morphological and statistical analysis was carried out, and common and specific features were considered. Se­veral cases are discussed to illustrate the occurrence of electromagnetic precursor signals before the recorded devastating earthquakes in Japan, China, Romania and other seismically active regions. A qualitative explanation is given for the study results.