STRESSED STATE OF THE EARTH'S CRUST IN THE WESTERN REGION OF THE SUNDA SUBDUCTION ZONE BEFORE THE SUMATRA-ANDAMAN EARTHQUAKE ON DECEMBER 26, 2004

Abstract

Reconstruction of the parameters of stress tensor based on focal mechanisms of earthquakes occurring before the Sumatra–Andaman earthquake (SAE) showed that deviatory stresses and all-round compression in the western Sunda subduction zone were distributed nonuniformly. Nonuniform state of the stress in this region is caused by the active sectors of the Andaman–Nicobar and Central Sumatra dextral strike-slip fractures. It was found that peculiarities in the development of the seismic fracture are caused by the revealed inhomogeneity of stresses.