Recurrence of Strong Earthquakes in the Active Hovd Fault Zone, Mongolian Altay

摘要

A geological, geomorphic, and paleoseismological study of paleoseismodislocation systems has been carried out. Numerous indications of prehistoric strong earthquakes expressed in sediments deposited in the fault-line region due to the formation of transient barrier lakes were revealed in the active Hovd Fault Zone on the eastern slope of the Mongolian Altay during a paleoseismological study of young near-surface sediments in trenches and dug pits. The paleosoils buried by these sediments were radiocarbon-dated. It has been established that the strongest earthquakes with magnitudes of ~8, which took place here 7200, 6600, 1500, and later than 700 years ago, substantially changed the topography in the epicentral zone. By analogy with the results of paleoseismological investigations performed in the Gorny Altay and the western Mongolian Altay, the data obtained shed light on the recurrence of the strongest seismic events in the Great Altay.