LATE PLEISTOCENE-HOLOCENE COSEISMIC DEFORMATIONS IN THE MALYI YALOMAN RIVER VALLEY (
Gorny Altai)
E.V. Deev1,2, I.D. Zolnikov3,2, E.Yu. Lobova1,2
1A.A. Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia 2Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090, Russia 3V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia
Keywords: Seismites, earthquakes, Quaternary deposits, Yaloman graben, Gorny Altai
Abstract
Palaeoseismological studies were performed within the Yaloman graben (Gorny Altai). Five Quaternary sections with coseismic deformation structures (seismites) have been recognized in the lower coarse of the Malyi Yaloman River. Traces of ancient earthquakes are localized at two levels (Late Pleistocene-Holocene). The most likely mechanisms of the seismite formation are brittle failure, liquefaction, and fluidization. The types of coseismic deformations and their sizes suggest that the Yaloman graben was the locus of prehistoric earthquakes with M ≥ 5-7, although modern-day seismic activity consists of smaller-magnitude earthquakes. This should be taken into account in assessing the seismic hazards during construction of gas pipeline to China and tourism infrastructure facilities.
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