SEISMIC IMPACTS OF LARGE EARTHQUAKES ON CENTRAL BAIKAL COASTAL AREAS: COMPREHENSIVE GEOLOGICAL AND GEOPHYSICAL ASSESSMENT
V.I. Dzhurik, E.V. Bryzhak, S.P. Serebrennikov, A.N. Shagun, A.Yu. Eskin
Institute of the Earth’s Crust, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
Keywords: Seismic impacts, baseline seismicity, earthquakes, seismic microzoning, accelerograms, frequency response, spectra, accelerations, resonance frequencies, Baikal coast
Abstract
We assess seismic impacts at various levels of seismic hazard zoning of the Central Baikal area using geophysical, seismotectonic and engineering-seismological studies and our methodological approaches. The implemented approaches help to identify zones of probable large earthquakes and specify their main features. This is necessary to properly assess input signals corresponding to the parameters of predicted large earthquakes. The basis for the reliability of the selected approaches and methods, relative to refining of baseline seismicity, are the manifestations of previously registered relatively large earthquakes in the study area. As far as seismic hazard zoning of particular territories is concerned, on a probabilistic basis, the registered data on the behavior of coastal water-saturated strata of loose sediments, according to local earthquake records, are quite reasonably accepted. The implemented approaches using a set of geophysical methods in the study areas allow us to improve the methods to predict maximum seismic impacts for different ground conditions in order to obtain a set of seismic data in the form of accelerograms, acceleration spectra, frequency curves and their parameters necessary to design earthquake-resistant constructions in the coastal areas of Lake Baikal. The studies are presented for the site located in the seismically active southeastern part of Central Baikal, in seismically worst ground conditions, within coastal areas.
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