Relatively small earthquakes of Javakheti Highland as the precursors of large earthquakes occuring in the Caucasus

Abstract

Javakheti Highland is one of the most seismic active regions of the Caucasus. The majority of earthquakes observed throughout the region occur within this small area (φ = 40.8° - 41.8°; λ = 43.3° - 44.3°). One can expect that exclusive seismic activity of Javakheti Highland testifies to global geophysical processes which take place throughout the Caucasus region. Based on the above-mentioned, of interest was to study variation with time of the number of earthquakes occurring in Javakheti region. We analysed some 695 relatively small earthquakes (2.5 ≤ M < 6.0) observed in Javalkheti Highland within the period of 1961-1992 with regard to large earthquakes M ≥ 6.0 of the region which occurred in the same period. It was found that each large earthquake of the Caucasus is anticipated by clear precursor in a form of an anomalous change in the number of relatively small earthquakes in Javakheti Highland. © European Geosciences Union 2003.