Large earthquakes in the Katun Fault zone (Gorny Altai): Paleoseismological and archaeoseismological evidence

摘要

Paleoseismological and archaeoseismological research in the Katun Fault zone in Gorny Altai reveals soft-sediment deformation structures (SSDS) in Late Quaternary sediments that fill the Yaloman graben. SSDS (seismites) were produced by large paleoearthquakes (M = 5-5.5) along the Katun Fault that occurred about 150 and 90 ka, in the 38-19 and 19-12.5 ka intervals, and after 12.5 ka. The event after 12.5 ka within the graben had a magnitude of M-s = 7.2-7.6. Traces of another event, shaking intensity I = V (ESI 2007 intensity scale), timed in the range from the 3rd century BC to the 1st century AD, were discovered during studies of a Scythian necropolis at the Chultukov Log 1 site located within the Manzherok graben in the northern end of the Katun Fault. Burial mounds near a mountain slope at the site are damaged by colluvium. Rocks of the same colluvium are scattered over 25 m off the slope and deform burial structures (cairns and stone rings, and inner stone walls of grave chambers), as well as the primary anatomical position of buried bodies, including those in burials not damaged by colluvium from outside. Thus, the Katun Fault was an active structure generating large earthquakes from the Middle Pleistocene through the Holocene. (C) 2018 Elsevier Ltd. All rights reserved.