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Ullah S.,Helmholtz Center Potsdam | Bindi D.,Helmholtz Center Potsdam | Pilz M.,Helmholtz Center Potsdam | Danciu L.,ETH Zurich | And 6 more authors.
Annals of Geophysics | Year: 2015

Central Asia is one of the seismically most active regions in the world. Its complex seismicity due to the dcollision of the Eurasian and Indian plates has resulted in some of the world’s largest intra-plate events over history. The region is dominated by reverse faulting over strike slip and normal faulting events. The GSHAP project (1999), aiming at a hazard assessment on a global scale, indicated that the region of Central Asia is characterized by peak ground accelerations for 10% probability of exceedance in 50 years as high as 9 m/s2. In this study, carried out within the framework of the EMCA project (Earthquake Model Central Asia), the area source model and different kernel approaches are used for a probabilistic seismic hazard assessment (PSHA) for Central Asia. The seismic hazard is assessed considering shallow (depth < 50 km) seismicity only and employs an updated (with respect to previous projects) earthquake catalog for the region. The seismic hazard is calculated in terms of macroseismic intensity (MSK-64), intended to be used for the seismic risk maps of the region. The hazard maps, shown in terms of 10% probability of exceedance in 50 years, are derived by using the OpenQuake software [Pagani et al. 2014], which is an open source software tool developed by the GEM (Global Earthquake Model) foundation. The maximum hazard observed in the region reaches an intensity of around 8 in southern Tien Shan for 475 years mean return period. The maximum hazard estimated for some of the cities in the region, Bishkek, Dushanbe, Tashkent and Almaty, is between 7 and 8 (7-8), 8.0, 7.0 and 8.0 macroseismic Intensity, respectively, for 475 years mean return period, using different approaches. The results of different methods for assessing the level of seismic hazard are compared and their underlying methodologies are discussed. © 2015 by the Istituto Nazionale di Geofisica e Vulcanologia. All rights reserved.

Mikhailova N.N.,Institute of Geophysical Researches | Mukambayev A.S.,Institute of Geophysical Researches | Aristova I.L.,Institute of Geophysical Researches | Kulikova G.,Institute of Geophysical Researches | And 3 more authors.
Annals of Geophysics | Year: 2015

In this work, we present the seismic catalogue compiled for Central Asia (Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan and Turkmenistan) in the framework of the Earthquake Model Central Asia (EMCA) project. The catalogue from 2000 B.C. to 2009 A.D. is composed by 33,034 earthquakes in the MLH magnitude (magnitude by surface waves on horizontal components widely used in practice of the former USSR countries) range from 1.5 to 8.3. The catalogue includes both macroseimic and instrumental constrained data, with about 32,793 earthquake after 1900 A.D. The main sources and procedure used to compile the catalogues are discussed, and the comparison with the ISC-GEM catalogue presented. Magnitude of completeness analysis shows that the catalogue is complete down to magnitude 4 from 1959 and to magnitude 7 from 1873, whereas the obtained regional b value is 0.805. © 2015 by the Istituto Nazionale di Geofisica e Vulcanologia. All rights reserved.

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