Georgia lies between the two mountain chains of the Greater Caucasus in the north and the Lesser Caucasus in the south. These two sets of mountains have both resulted from the continuing effects of the collision between the Arabian Plate and the Eurasian Plate. The Greater Caucasus consists of a southward-directed fold and thrust belt that has been active since the Oligocene. Racha lies close to the southern margin of this thrust belt and the earthquake is interpreted to be caused by rupture of the active thrust front.