Abstract

Central Asia is a region of large crustal compression due to the collision of the Eurasian and Indian plates. The significant convergence and crustal shortening is located within the Pamir and Tien Shan belts, and the deformation resulted in many Mw7 earthquakes throughout the region, recorded historically as well as instrumentally. Consequently, the seismic hazard in this region is of high interest.

Previous hazard studies are often based on either earthquake data or geological information. Hence, seismic hazard assessments have not yet considered models combining the two types of information. In this study, we consider the existing faults together with the earthquake catalogs available for the region (from 2000 B.C. to A.D. 2016). The different types of data are combined in a probabilistic hazard assessment using a logic‐tree approach. This approach follows the recommendations of Stein and Friedrich (2014). The use of a logic‐tree approach lets us quantify the seismic hazard in the region while considering the epistemic uncertainty in the computations. The seismic hazard is presented in terms of peak ground acceleration (PGA) and spectral acceleration for different periods, all shown on maps for a return period of 475 yrs (10% exceedance probability in 50 yrs). The hazard curves and uniform hazard spectra are calculated for the four capitals in the region: Almaty, Bishkek, Dushanbe, and Tashkent. The largest expected ground motions are found in southern Tien Shan and northern Pamir, where PGA is found to be in the order of 0.4g0.47g.

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