STRAIN AND DISPLACEMENT RATES DURING A LARGE EARTHQUAKE IN THE SOUTH BAIKAL REGION
V.Yu. Timofeeva, D.G. Ardyukova, E.V. Boikoa, E.I. Gribanovab, V.M. Semibalamutb, A.V. Timofeeva, A.V. Yaroshevichc
aA.A. Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia
bSeismological Division of the Geophysical Survey, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Lavrent'eva 13/3, Novosibirsk, 630090, Russia
cIrkutsk Territorial Center for the State Monitoring of the Geologic Environment, ul. Klary Tsetkin 9a, Irkutsk, 664039, Russia
Keywords: Adit strainmeters and tiltmeters, borehole measurements, GPS measurements, strain and displacement rates, earthquakes and coseismic changes, Baikal region
Pages: 798-816
Abstract
Crustal kinematic characteristics such as strain and displacement rates are important in the monitoring of present-day processes in zones of seismic and industrial hazard. Strain measurements on different temporal and spatial baselines reveal potentially hazardous zones. Data on coseismic displacements and strain can be used to refine earthquake models, and long-term characteristics are important in searching for earthquake precursors and studying the rheology of the crust and fault zones. Tilt measurements in the adit of the Talaya seismic station (51.68?N, 103.64?E, South Baikal region) began in 1985; strain measurements, in 1990; and GPS measurements, in 2000.
The data reflect time variation in the local strain parameters and permit a comparison with the GPS data on the region and western Central Asia. The data on strain variations obtained in the Ala-Archa underground observatory (42.63?N, 74.50?E, North Tien Shan) are analyzed together with those obtained in the region by GPS methods.
Strain rates on very long baselines were determined using data from permanent IGS stations for Central Asia - the territory expanding from Dzungaria in the south to the Siberian Platform in the north and from the Tien Shan in the west to Lake Baikal in the east. We consider the example of using strain gaging and GPS data to construct a dislocation model and refine the parameters of the Kultuk earthquake (South Baikal region, 27 August 2008, M = 6.3).
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