ABOVIAN S.B - Institute of Geological Sciences of the National Academy of Sciences of the Republic of Armenia, ۲۴a Marshal Bagrarnyan Ave.. ۳۷۵۰۱۹, Yerevan, Republic of Armenia.

The Spitak earthquake is confined to the zone of deep faults, occurred in the result of north-oriented subduction of the Arabian plate under the south edge of the Eurasian one. Within the Armenian Highland the movement of masses to the north is expressed in subduction of Folding zone of Armenia under the Sevan zone and the Sevan one under the Somkheto-Karabakii zone along the Pambak-Sevan deep fault. The periodicity of eathquakes and a differentiated character of rupture dislocation evolution indicate an interrupted translational development of deep faults, in the Spitak region there is a joint of the Pambak-Sevan latitudinal fault and the diagonal Ghukasian-Alavar and Markara-Alaverdy faults, along which permanent increase of pressure occurs in passive stage of the evolution. Further mass motion relative to each other in the fault zone produces shear deformation (according to the principle of Bridgmen's anvil), which tkgt.Irs explasion process of 'great power an earthquake (active stage). ['he exothermic reaction with formation of detonation wave take place. The reaction time is about seconds, the temperature is about ۲۰۰۰°C [۱].