First Steps toward a Reassessment of the Seismic Risk of the City of Dushanbe (Tajikistan)

Abstract

Online Material: Table detailing station installation sites and recording times. The country of Tajikistan is located in the Asia–India continental collision zone where the northward‐moving Indian plate indents the Eurasian plate (Molnar and Tapponnier, 1975). The Asian lithosphere being impinged upon by the shallow northward underthrusting Indian lithosphere has resulted in high‐mountain topography, which is subject to active deformation and contemporary faulting, and, consequentially, frequent earthquakes (e.g., Gubin, 1960; Burtman and Molnar, 1993). According to the Global Seismic Hazard Map (Giardini, 1999), almost the entire country exhibits a high‐hazard level with intensities of VIII–IX for a 5% exceedance in 50 years. Most of the earthquakes that occur in these fault zones are crustal events with dominating thrust faulting along the Pamir front, whereas on the eastern edge of the Pamir the style of deformation is generally characterized by oblique thrusting with a component of strike‐slip motion. Thrust‐type events beneath the Tadjik Depression, a compressional intermountain basin in the western part of the country, indicate that both the sedimentary rocks and the basement are involved in shortening (Fan et al. , 1994; Delvaux et al. , 2013). Although archaeological remnants dating to the fifth century B.C. have been discovered in this area, there is little to suggest that Dushanbe, the Tajik capital, was more than a small village until the early twentieth century. Therefore, there exists only a relatively short record of strong earthquakes in the area (e.g., the 1907 M 7.3 Karatag earthquake and the 1949 M 7.4 Khait earthquake) in comparison with other parts of Central Asia. The General Seismic Zoning map for the former Soviet Union (GSZ‐78) associated an intensity of IX to Dushanbe, with a recurrence interval of 1000 years (Bune and Gorshkov, 1980). Recently, Nurmangambetov et al. (1999) calculated refined return periods for intensities IX and …