The Spitak morphostrucmral node and the earthquake of December 7, 1988

Abstract

The Spitak morphostructural node is formed by two lineaments intersection: the Pambak-Sevan longitudinal and Transcaucasian transversal ones. Both vertical and tangential neotectonic movements are recorded within the Pambak-Sevan zone. The nodal area is distinguished by most differentiated topography of ridges and basins formed within the region of large lineaments intersection. Isoseists of the Spitak earthquake outline the nodal area. The earthquake location is connected with a previously existed fault which was not however the most active one. Some traces of older earthquakes are found within the region. The region does not form a landscape unity, as it lies at the boundary of different physical-geographical regions and includes various elements.