Active tectonics and paleoseismicity of the eastern Issyk-Kul Basin (Kyrgyzstan, Tien Shan)
Active tectonics and paleoseismicity of the eastern Issyk-Kul Basin (Kyrgyzstan, Tien Shan)
Russian Geology and Geophysics (March 2021) 62 (3): 263-277
- active faults
- Asia
- basins
- Cenozoic
- Commonwealth of Independent States
- earthquakes
- fault scarps
- faults
- Holocene
- intermontane basins
- Issyk-kul Lake
- Kyrgyzstan
- Neogene
- neotectonics
- paleoseismicity
- Quaternary
- reverse faults
- sedimentary rocks
- sedimentary structures
- sediments
- seismicity
- seismites
- tectonics
- Tertiary
- Tien Shan
- Issyk-kul Basin
- Ichketosma Uplift
- Karkara Fault
- Birbash Uplift
- Tosma Uplift
- Issyk-kul Fault
- Orgochor Uplift
The Malyi Orgochor, Orgochor, Birbash, Sukhoi Ridge, Ichketosma, and Tosma uplifts in the eastern Issyk-Kul basin are fault-related anticlinal folds composed of Neogene and Quaternary sediments involved in tectonic movements. The folds have asymmetric transversal profiles, with low-angle southern limbs and steep northern limbs cut by segments of the South Issyk-Kul and Karkara reverse faults reactivated in the late Quaternary. The location and geometry of the two faults, which both show reverse and left-lateral strike slip components, correspond to neotectonic propagation of deformation from the Terskey-Ala-Too Range over almost the whole eastern Issyk-Kul basin. Judging by primary and secondary coseismic surface deformation in the area, the South Issyk-Kul and Karkara faults repeatedly generated large earthquakes (M > or =7, I > or =9) in the Late Pleistocene and Holocene. According to trenching results, the historical earthquakes that occurred in the first and 10-11th centuries accommodated motions on the South Issyk-Kul fault. The new seismotectonic and paleoseismicity data from the eastern Issyk-Kul basin provide updates to its seismic potential.