Underestimated seismic hazard in the south of the Issyk-Kul Lake region (northern Tian Shan)  

作　　者：A.M. Korzhenkov E.V. Deev 

机构地区：[1]O.Yu. Schmidr Institute of Physics of the Earth. Russian Academy of Sciences, Moscow, Russia [2]b.n.yeltsyn Kyrgyz-Russian Slavic University, Kievskaya Str 44. Bishkek. Kyrgyzstan [3]A.A. Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia [4]Novosibirsk State University,Novosibirsk, Russia

出　　处：《Geodesy and Geodynamics》2017年第3期169-180,共12页大地测量与地球动力学（英文版）

基　　金：financial support of ISTC grants Nos.KR-2011 and G-2153

摘　　要：The Tian Shan Mountains were formed in the result of the India-Eurasia collision, which leads to cre- ation of contrast high-mountain relief and world known seismic activity. The seismic catastrophes, recorded instrumentally, have occurred to the north of the Issyk-Kul Lake region. There are also known significant earthquakes with magnitude being about 7 in western and eastern parts of the mentioned lake region. Only in the south of the Issyk-Kul depression the strong earthquakes recorded by the seismic network were not known. Our recent study in the south of the lssyk-Kul Lake region has revealed numerous active tectonic structures related to South Issyk-I（ul Fault： faults and folds, responsible for strong earthquakes＇ occurrence. These were historical and paleoseismic defornlations which led to changes in relief： fault scarps and significant rockslides. We have also found spectacular deformations in archeological monuments. All these deformations testify the location of epicentral areas of two strong historic （about llth and 16th （？） centuries AD） and paleoearthquakes （Holocene and Late Pleistocene）. Magnitude of ancient seismic events, according to parameters of the revealed fault scarps, were Ms 〉 7 and seismic intensity I 〉 IX. All revealed seismic deformations are located to adyrs （piedmonts） of the Terskey Ala-Too range bordered of the lssyk-Kul Lake depression in the south. Their formation is described by the model of a fault which rupture plane becomes shallower southward. This model is complicated by the presence of reverse thrusts. Here, we should admit the existence of a single zone of South lssyk-Kul Fault which is a long-lived feature which separates the structures with the different regime of movements during the Neotectonic time. All obtained data led us to a conclusion of significant underestimation of the seismic hazard in southern lssyk-Kul Lake region.The Tian Shan Mountains were formed in the result of the India-Eurasia collision, which leads to cre- ation of contrast high-mountain relief and world known seismic activity. The seismic catastrophes, recorded instrumentally, have occurred to the north of the Issyk-Kul Lake region. There are also known significant earthquakes with magnitude being about 7 in western and eastern parts of the mentioned lake region. Only in the south of the Issyk-Kul depression the strong earthquakes recorded by the seismic network were not known. Our recent study in the south of the lssyk-Kul Lake region has revealed numerous active tectonic structures related to South Issyk-I（ul Fault： faults and folds, responsible for strong earthquakes＇ occurrence. These were historical and paleoseismic defornlations which led to changes in relief： fault scarps and significant rockslides. We have also found spectacular deformations in archeological monuments. All these deformations testify the location of epicentral areas of two strong historic （about llth and 16th （？） centuries AD） and paleoearthquakes （Holocene and Late Pleistocene）. Magnitude of ancient seismic events, according to parameters of the revealed fault scarps, were Ms 〉 7 and seismic intensity I 〉 IX. All revealed seismic deformations are located to adyrs （piedmonts） of the Terskey Ala-Too range bordered of the lssyk-Kul Lake depression in the south. Their formation is described by the model of a fault which rupture plane becomes shallower southward. This model is complicated by the presence of reverse thrusts. Here, we should admit the existence of a single zone of South lssyk-Kul Fault which is a long-lived feature which separates the structures with the different regime of movements during the Neotectonic time. All obtained data led us to a conclusion of significant underestimation of the seismic hazard in southern lssyk-Kul Lake region.

关 键 词：Paleoseismic deformations Fault scarps Trenching Kadzhi-Say river Tossor river lssyk-Kul Lake Tian Shau Seismic hazard assessment 

分 类 号：P315[天文地球—地震学]