TY - JOUR

T1 - Paleoseismicity of Adyr Faults

T2 - The Kokonadyr–Tegerek Fault, Southwestern Issyk-Kul Region, the Tien Shan

AU - Korzhenkov, A. M.

AU - Abdieva, S. V.

AU - Gladkov, A. S.

AU - Deev, E. V.

AU - Liu, J.

AU - Mazeika, J. V.

AU - Rogozhin, E. A.

AU - Rodkin, M. V.

AU - Sorokin, A. A.

AU - Turova, I. V.

AU - Fortuna, A. B.

N1 - Publisher Copyright: © 2019, Pleiades Publishing, Ltd. Copyright: Copyright 2019 Elsevier B.V., All rights reserved.

PY - 2019/9/1

Y1 - 2019/9/1

N2 - We have studied paleoseismicity along the adyr (piedmont) Kokonadyr–Tegerek fault zone in the SW Issyk-Kul region. We have shown that although earthquake slip continues in the tectonic contact zone between the Paleozoic rocks of the Kokonadyr–Tegerek uplift and the Quaternary deposits of the Alabash–Konuroleng trough, still most earthquake-generating ruptures visible at the surface are moving for some hundreds of meters southward from the abovementioned adyr fault. This process leads to the formation of multislip earthquake scarps and compensation grabens behind them. Radiocarbon dating identified four large Holocene earthquakes along the Kokonadyr–Tegerek fault zone that occurred during the following time spans: 1771‒1785, 1440‒1515, as well as probably 2310–745 B.C. and 6400–5300 B.C. Judging from the parameters of these ruptures, or earthquake scarps, their magnitudes were greater than or equal to 7 and the intensity of shaking was Io ≥ IX. Vigorous seismic activity has gone on along the Kokonadyr–Tegerek fault zone since at least the Middle Quaternary. The relevant evidence includes uplifted and abandoned valleys of this age in the eponymous uplift and considerable accumulations of lacustrine deposits in the northern Alabash–Konuroleng depression. The thick sedimentary sequence was caused by glacier melting on the northern slope of the Terskei Ala-Too mountain range, while the abandoned valleys indicate considerable tectonic damming. The most suitable model to explain the formation of adyrs (piedmont areas or foothills) in the southern Issyk-Kul basin seems to be a model that envisages a low-angle northward propogating or southward dipping main fault that is complicated with reverse movements. All the materials acquired in this study can be used to develop a new Earthquake Hazard Map for the Republic of Kyrgyzstan.

AB - We have studied paleoseismicity along the adyr (piedmont) Kokonadyr–Tegerek fault zone in the SW Issyk-Kul region. We have shown that although earthquake slip continues in the tectonic contact zone between the Paleozoic rocks of the Kokonadyr–Tegerek uplift and the Quaternary deposits of the Alabash–Konuroleng trough, still most earthquake-generating ruptures visible at the surface are moving for some hundreds of meters southward from the abovementioned adyr fault. This process leads to the formation of multislip earthquake scarps and compensation grabens behind them. Radiocarbon dating identified four large Holocene earthquakes along the Kokonadyr–Tegerek fault zone that occurred during the following time spans: 1771‒1785, 1440‒1515, as well as probably 2310–745 B.C. and 6400–5300 B.C. Judging from the parameters of these ruptures, or earthquake scarps, their magnitudes were greater than or equal to 7 and the intensity of shaking was Io ≥ IX. Vigorous seismic activity has gone on along the Kokonadyr–Tegerek fault zone since at least the Middle Quaternary. The relevant evidence includes uplifted and abandoned valleys of this age in the eponymous uplift and considerable accumulations of lacustrine deposits in the northern Alabash–Konuroleng depression. The thick sedimentary sequence was caused by glacier melting on the northern slope of the Terskei Ala-Too mountain range, while the abandoned valleys indicate considerable tectonic damming. The most suitable model to explain the formation of adyrs (piedmont areas or foothills) in the southern Issyk-Kul basin seems to be a model that envisages a low-angle northward propogating or southward dipping main fault that is complicated with reverse movements. All the materials acquired in this study can be used to develop a new Earthquake Hazard Map for the Republic of Kyrgyzstan.

KW - adyrs

KW - compensation graben

KW - earthquake scarps

KW - Issyk-Kul

KW - Tien Shan

KW - underthrusting

UR - http://www.scopus.com/inward/record.url?scp=85074102522&partnerID=8YFLogxK

U2 - 10.1134/S0742046319050026

DO - 10.1134/S0742046319050026

M3 - Article

AN - SCOPUS:85074102522

VL - 13

SP - 305

EP - 322

JO - Journal of Volcanology and Seismology

JF - Journal of Volcanology and Seismology

SN - 0742-0463

IS - 5

ER -