Georgia

Georgia lies at the heart of the Greater Caucasus collision zone, where the Arabian Plate pushes northward into Eurasia at approximately 25–30 millimetres per year. This convergence has built the Greater Caucasus mountain range — one of the world's most geologically young and active mountain systems — through ongoing thrust faulting and crustal shortening. The principal active [[fault]] systems in Georgia include the Racha Fault in the central Greater Caucasus, the Borjomi-Kazbegi Fault system, and various thrust faults along the mountain front. The Kartli Basin in central Georgia is a tectonic depression underlain by thick sediments that can amplify shaking. Southern Georgia, bordering Armenia and Azerbaijan, shares in the Lesser Caucasus seismicity driven by the same Arabian-Eurasian collision.

Georgia's seismic history is marked by repeated destructive events. The 1991 Racha earthquake sequence produced a main shock of magnitude 7.0 on April 29, followed by a magnitude 6.4 aftershock on June 15, killing over 100 people and causing extensive damage to the mountain villages of the Racha region. Buildings constructed of stone rubble masonry were particularly vulnerable. Earlier significant events include the 1920 Gori earthquake and historical accounts of destructive earthquakes affecting Tbilisi and other population centres over the centuries. The old city of Tbilisi itself sits in a seismically active zone along the Mtkvari River valley, and paleoseismic evidence suggests major earthquakes have struck the region in prehistoric times.

The deeper geological setting of Georgia involves the collision and suturing of multiple crustal terranes over the past 50 million years. The Greater Caucasus represents the active collision front, where thick sedimentary sequences deposited in the former Tethys seaway have been compressed and thrust southward over the South Caucasus region. Crustal GPS data confirms that the Greater Caucasus is still actively shortening at several millimetres per year. The Borjomi-Kazbegi zone is an important structural boundary between the Greater and Lesser Caucasus tectonic domains. Volcanic centres in the Javakheti Plateau of southern Georgia reflect the same deep mantle processes that accompany the ongoing collision. The [[epicenter]] distribution of Georgian earthquakes traces the geometry of the major thrust systems clearly, with the highest seismicity concentrated in the western Greater Caucasus region.