合作市隐伏断层控制性地球化学探测场地试验  

Field Test on the Geochemical Detection of Concealed Fault in Hezuo City

作　　者：张慧[1,2] 苏鹤军[1,2] 李晨桦[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]兰州地球物理国家野外科学观测研究站,甘肃兰州730000

出　　处：《地震工程学报》2013年第3期618-624,共7页China Earthquake Engineering Journal

基　　金：地震科技星火计划项目(XH12048)

摘　　要：近年来在城市活断层探测中广泛开展了土壤气探测的工作。本文在合作市周边地区选择2个位于西秦岭北缘断裂西段具有典型断层露头的甘加、黄香沟场地开展了现场土壤气汞、氡浓度测试。主要结论有:(1)断层带存在明显汞、氡浓度异常,曲线的峰值能够很好地对应断层位置,而且其曲线形态能够较好的反映出断层性质与几何形态;(2)异常段上方氡、汞的峰值异常一般比背景值高出1.5倍以上,且具有成组特征(即在断层带上方超过背景值1.5倍以上的点2个以上),并具有典型正弓形曲线形态;(3)合作市地处草原,地表覆盖层匀一、稳定,外界干扰较小,植被覆盖好,不仅有利于土壤气汞、氡浓度地球化学方法进行隐伏断裂的控制性探测,同时也有利于对已知断裂活动性时空变化特征进行跟踪探测研究。In recent years,soil gas has rapidly developed for wide application urban active fault detection because of its fast,convenient,high-efficiency,and low-cost characteristics.The measurement methods of Hg and Rn soil gases are established and are helpful for studying active fault detection and the hazard assessment.The focus of this research is determination of the position of the concealed fault and its occurrence to ultimately provide a target for further drilling and costeaning through analysis of the anomaly concentration characteristics of Rn and Hg gases in the soil.Due to the particularity of urban environmental conditions and the complexity of geological conditions to obtain more accurate and reliable results and thus better scientific analysis conclusions,it is necessary to conduct experimental research on the fault soil gas anomaly characteristics and influencing factors in the typical fields that have fault outcrops or drilling data prior to large-scale field detection and feature analysis.The goal of this project is to promote better control of geochemical exploration in Hezuo.The Hg and Rn soil gas concentrations were tested in two typical fault outcrops of Ganjia and Huangxiang gullies near Hezuo city,which is located in the western region of the northern rim of West Qinling.The results show that obvious anomalous concentrations of Hg and Rn gases exist in the fault zone,the peak of the concentration curve corresponds well to the fault location,and its curve can better reflect the nature and geometry of the fault.The results of six Rn and Hg measuring lines on two experimental sites indicate that the anomaly peak values are generally 1.5 times higher than the background values and are grouped.In particular,the anomaly points are usually greater than twice the 1.5 background value on the fault zone,and the curve exhibits the typical bow shape; the single abnormal point is considered to be the interference factor during observation.The Huang-Xiang gully on the west Qinling fault test site is the most ty

关 键 词：合作市 活动断层 土壤气 氡、汞地球化学 

分 类 号：P315.724[天文地球—地震学]