PREMONITORY ACTIVATION OF EARTHQUAKE FLOW - ALGORITHM M8

Thirty-nine out of the 44 strongest earthquakes which have recently occurred in different regions of the world are preceded by specific activation of the earthquake flow in the lower magnitude range. This activation is depicted by the algorithm M8, which was designed for diagnosis of times of increased probability (TIPs) of strong earthquakes. A TIP refers to a time period of 5 yr and an area of linear size several times larger than that of the incipient earthquake source. Altogether the TIPs diagnosed in this study occupy less than 20%, and the times of expectation (TEs) about 10% of the total space-time domain considered. These results constitute an argument in favor of at least partial self-similarity of the earthquake flow in diverse seismotectonic environments and magnitude ranges. It also implies the possibility of intermediate-term prediction of the strongest earthquakes in these regions. Such prediction may be used for precautionary measures. © 1990.