SEISMIC-HAZARD ASSESSMENT FOR ULAANBAATAR ( Mongolia ) ON THE BASIS OF SEISMOGEOLOGICAL STUDIES
V.S. Imaeva, O.P. Smekalina, A.L. Stromb, A.V. Chipizubova, and A.A. Syas'koc
aInstitute of the Earth's Crust, Siberian Branch of the Russian Academy of Sciences, ul. Lermontova 128, Irkutsk, 664033, Russia
bCenter of the Geodynamic Survey of Gidroproekt JSC, Volokolamskoe sh. 2, Moscow, 125993, Russia
cTechnical Institute of M.K. Ammosov Northeastern Federal University, ul. Kravchenko 16, Neryungri, 678960, Russia
Keywords: Seismogenic fault, radiocarbon age, trenching, paleoearthquake, geophysical section
Pages: 906-915
Abstract
The Gunzhin Fault is a tectonic structure in the southern Hentiyn arched uplift (central Mongolia). A fragment of this fault, exposed by two paleoearthquakes, is traced northeastward for ~25 km from the northern periphery of Ulaanbaatar. The first comprehensive seismogeological studies here were aimed at determining the seismic potential of seismogenic structures on the basis of the dislocation parameters. Judging by the strain amplitudes and length, earthquakes with a magnitude of >7.0 might be generated here. The paleoearthquake was dated by the radiocarbon method at 7800-4667 B.C. Seismogenic zones with a high seismic potential were identified in central Mongolia for the first time. Dextral strike-slip faults were observed here among active NE-trending faults, suggesting the presence of E-W compressive stress.
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