Natural Hazards and Earth System Science www.nat-hazards-earth-syst-sci.net 1561-8633 1684-9981 3 3/4 2003 10.5194/nhess-3-165-2003 http://www.nat-hazards-earth-syst-sci.net/3/165/2003/ http://www.nat-hazards-earth-syst-sci.net/3/165/2003/nhess-3-165-2003.html http://www.nat-hazards-earth-syst-sci.net/3/165/2003/nhess-3-165-2003.pdf 165 170 0000-00-00 Relatively small earthquakes of Javakheti Highland as the precursors of large earthquakes occuring in the Caucasus M. Kachakhidze N. Kachakhidze R. Kiladze V. Kukhianidze G. Ramishvili Tbilisi State University, Chavchavadze st. 2, Tbilisi 380028, Georgia Abastumani Astrophysical Observatory, Kazbegi av. 2a, Tbilisi 380060, Georgia 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 (<font face="Symbol">f</font> = 40.8° – 41.8° ; <font face="Symbol">l</font> = 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 <u>&lt;</u> M &lt; 6.0) observed in Javalkheti Highland within the period of 1961–1992 with regard to large earthquakes M <u>&gt;</u> 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.