Active tectonics and paleoseismicity of the eastern Issyk-Kul Basin (Kyrgyzstan, Tien Shan)

• Published in: Russian geology and geophysics Vol. 62; no. 3; pp. 263 - 277
• Main Authors: Korzhenkov, A. M, Deev, E. V, Turova, I. V, Abdieva, S. V, Ivanov, S. S, Liu, J, Mazeika, I. V, Rogozhin, E. A, Strelnikov, A. A, Fortuna, A. B, Usmanova, M. T
• Format: Journal Article
• Language: English
• Published: Allerton Press 01.03.2021
• Subjects: active faults; Asia; basins; Birbash Uplift; Cenozoic; Commonwealth of Independent States; earthquakes; fault scarps; faults; Holocene; Ichketosma Uplift; intermontane basins; Issyk-kul Basin; Issyk-kul Fault; Issyk-kul Lake; Karkara Fault; Kyrgyzstan; Neogene; neotectonics; Orgochor Uplift; paleoseismicity; Quaternary; reverse faults; sedimentary rocks; sedimentary structures; sediments; seismicity; seismites; Seismology; Structural geology; tectonics; Tertiary; Tien Shan; Tosma Uplift
• ISSN: 1068-7971; 1878-030X
• DOI: 10.2113/RGG20194125

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 ≥7, I ≥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.