岷县漳县6.6级地震后申都乡地窖宏观异常现象及其机理探讨  

Study on the Mechanism of the Macroscopic Anomaly of a Cellar in Shendu following the Minxian-Zhangxian M_s6.6 Earthquake

作　　者：李晨桦[1,2] 张慧[1,2] 张昱[1] 陈兰庆[1] 苏鹤军[1,2] 

机构地区：[1]中国地震局兰州地震研究所,甘肃兰州730000 [2]中国地震局地震预测研究所兰州科技创新基地,甘肃兰州730000

出　　处：《地震工程学报》2013年第4期835-839,共5页China Earthquake Engineering Journal

基　　金：中国地震局地震预测研究所基本科研业务项目(2013IESLZ04);地震科技星火计划项目(XH12048)

摘　　要：2013年7月22日甘肃岷县漳县M_s6.6地震后岷县申都乡某地窖出现冒白色烟雾的宏观异常现象。本文通过土壤气Rn、Hg现场检测和采样后气相色谱检测、生物显微镜观察结果,探讨了气体来源、赋存和运移机理以及异常形成的物理化学机制。认为该点具有灵敏的断层活动响应,可作为今后开展断层活动及未来甘东南地震趋势预测判定的断层土壤气监测点进行长期监测。Precursory and coseismic anomalies of fault gas often appear prior to and following an earthquake.Following the Minxian-Zhangxian MS6.6 earthquake,an abnormal phenomenon occurred in Shendu,Minxian,and China,in which a large amount of white smoke was observed in a cellar.Physical evidence obtained recently demonstrates that deep fluid has a significant influence on earthquake gestation and that earthquakes involve a large number of chemical processes and may not be results of purely mechanical or physical processes.These deep fluids,which migrate to the ground surface,originate from the dehydration of hydrous minerals and contain a substantial amount of information about the crust and mantle.Thus,gases present in the soil offer the same information.Convenient,low-cost methods of measuring soil gases such as Hg and Rn that have been developed for wide application to active fault detection have also proven to be highly efficient for hazard assessment.The anomaly site is located in the southeastern Gansu area,which is at the northeast edge of the Tibetan Plateau in the middle of the North-South-trending seismic belt.Because this belt contains a group of active faults that produce intense tectonic activity in its boundary and interior,it is often used to study seismic hazards and the background field of southeastern Gansu.In this study,Rn and Hg soil gases collected near a cellar in Shendu,Minxian,following the Minxian-Zhangxian MS6.6 earthquake were tested on site.The results were combined with those of test samples examined by gas chromatography and a biological microscope to analyze the source,storage,transport,and physical and chemical mechanisms of the underground gases.The results reveal that following the earthquake,Rn and Hg values,in addition to those of CO2 and He,were higher;therefore,the deep gases migrated upward along ruptures and fractures during the earthquake.In addition,white smoke observed in the cellar and examined by a biological microscope was found to contain a large amount of sporopollen.We con

关 键 词：岷县漳县MS6 6地震 异常现象 断层土壤气 甘东南地区 

分 类 号：P315.721[天文地球—地震学]