新疆北天山地区断裂带断层土壤气的地球化学特征  

GEOCHEMICAL CHARACTERISTICS OF SOIL GAS IN THE FAULT ZONES OF NORTH TIANSHAN,XINJIANG

作　　者：蒋雨函 高小其 杨朋涛 刘冬英 孙小龙 向阳 朱成英[2] 汪成国[2] JIANG Yu-han;GAO Xiao-qi;YANG Peng-tao;LIU Dong-ying;SUN Xiao-long;XIANG Yang;ZHU Cheng-ying;WANG Cheng-guo(Key Laboratory of Crustal Dynamics,National Institute of Natural Hazards,Ministry of Emergency Management of China,Beijing 100085,China;Earthquake Agency of Xinjiang Uygur Autonomous Region,Urumqi 830011,China)

机构地区：[1]应急管理部国家自然灾害防治研究院,地壳动力学重点实验室,北京100085 [2]新疆维吾尔自治区地震局,乌鲁木齐830011

出　　处：《地震地质》2022年第6期1597-1614,共18页Seismology and Geology

基　　金：国家重点研发计划项目(2019YFC1509203);中国地震局地壳应力研究所基本科研业务专项(ZDJ2017-27);中国地震局地质研究所国家野外科学观测研究站研究项目(NORSCBS21-02)共同资助。

摘　　要：断层土壤气测量是揭示断层性质与断裂活动的重要地球化学方法。文中在新疆北天山2个地震危险区中的博罗科努-阿其克库都克断裂、库松木契克山前断裂、独山子-安集海断裂、霍尔果斯-吐谷鲁断裂、喀什河断裂、那拉提断裂等6条断裂带上布设了8条断层土壤气测线,共进行了6、7期测量。文中依据多期断层土壤气流动测量结果,分析了断层土壤气的空间分布特征,并分别讨论了断裂带活动性及区域地震危险性。结果表明:(1)土壤气组分Rn是研究断裂带分布、指示断裂破碎位置及判断断层活动性的有效气体,在库松木契克山前断裂和霍尔果斯-吐谷鲁断裂的测线上,除断层出露处的测点外,还存在其他测点出现Rn浓度峰值的现象,因此这2条断裂带除了断层出露处还存在其他断裂破碎位置。(2)在库松木契克山前断裂、那拉提断裂以及霍尔果斯-吐谷鲁断裂所布设的测线上,Rn浓度的最高值分别为99802Bq/m^(3)、80549Bq/m^(3)、78834Bq/m^(3),不仅高于其他断裂带测线的Rn浓度值,还高于新疆呼图壁北断裂的Rn浓度值,说明上述3条断裂的断层活动性较强。(3)北天山温泉—精河地震危险区内小地震频率相对较低,区域应力积累程度相对较高,断层活动性强,更易发生中强震,存在一定的地震危险性。未来对北天山温泉—精河地震危险区内的断层土壤气体地球化学开展监测与深入研究,对判断北天山地区的地震危险性具有重要意义。文中的结果可为分析新疆北天山地区断裂带释放气体特征及指导地震台站勘选、布设和震情跟踪等提供地球化学资料与技术支撑。The soil gas concentration and escape rate value can sensitively and objectively reflect the underground state of stress,strain and tectonic activity.In addition,abnormal phenomena of fault soil gas often occur before and after seismic activity.It is often used to identify the active state of fault zones,explore hidden faults and assess earthquake risk.As an important geochemical method,the soil gas measurement is an important geochemical method to reveal fault properties and fault activities and other tectonic activities.In this study,we laid out 8 measurement lines of soil gas along the Borokonu-Aqikkuduk Fault,the Kusongmuchike piedomont fault,the Dushanzi-Anjihai Fault,the Horgos-Tugulu Fault,the Kashi River Fault and the Nalati Fault in two earthquake risk areas of the north Tianshan Mountains in Xinjiang,namely,the“North Tianshan Wenquan-Jinghe M7 earthquake risk area”and the“Wusu-Hejing M6 earthquake risk area”.From 2017 to 2020,a total of 6~7 phases of measurements were carried out to make clear the distribution characteristics of Rn,CO2and Hg concentrations along these faults.There have been many moderate/strong earthquakes near the above-mentioned faults,and it is of great significance of soil gas measurement on these faults for us to gain a deep understanding of the fault activity characteristics and earthquake risk.In this paper,the spatial distribution characteristics of fault soil gas are analyzed based on the multi-period measurement results,and the activity of the fault zone and the regional earthquake risk are discussed respectively.The results show that:(1)The Rn concentrations are more stable than that of CO_(2)and Hg along each measurement line,which can be used as an effective indicator gas for analyzing the distribution of fault zones,indicating the location of fault fractures and judging the activity of faults.Since there are many interference factors of CO_(2)and Hg concentrations,they can be used as an auxiliary means.In most cases,the distribution of Rn concentrations on other me

关 键 词：氡 汞 二氧化碳 断层土壤气 北天山地区 

分 类 号：P315.725[天文地球—地震学]