Seismic Activity of the Khambinskii Fault (Southwestern Transbaikalia)

Abstract

Abstract —The paper presents results of a seismogeological study based on analysis of seismic data and historical facts about the seismic activity of the Khambinskii fault zone. According to the data obtained, a genetic type of dislocations on conjugate faults (Gusinoe Ozero and Orongoi paleoseismogenic structures) is related to reverse faults with a strike-slip component. Geophysical studies of the Gusinoe Ozero structure have determined the dip of the fault plane toward the mountain framing of the depression and its outcrop at the bottom of the seismic scarp. The significant seismic potential of the Khambinskii fault is responsible for the maximum intensity of shocks in the nearby cities and settlements of southeastern Transbaikalia. The seismic fault activity has been confirmed by the historical earthquakes of 1856 and 1885, the M = 5 earthquake that occurred on 2 October 1980, and at least two prehistoric earthquakes. The latest of the latter occurred no earlier than ~4 ka and had M = 7.0–7.3, while the earliest was even more intense and took place in the first half of the Holocene, no later than ~6 ka.