摘要
在河北怀涿盆地的郝家坡和小水峪布设两条测线开展了四期土壤气Rn,CO_(2)和Hg的浓度测量,并基于此研究该盆地北缘断裂带南西段和北东段土壤气地球化学特征的空间分布差异及其与断裂活动的关系。结果显示:郝家坡剖面土壤气Rn, CO_(2)和Hg的浓度平均值分别为8 371.16 Bq/m^(3),0.85%和14.82 ng/m^(3);小水峪剖面土壤气Rn,CO_(2)和Hg的浓度平均值分别为2 813.18 Bq/m^(3),0.42%和13.08 ng/m^(3),可见郝家坡地区土壤气Rn,CO_(2)和Hg的浓度平均值均高于小水峪地区,这种浓度空间分布的差异性可能是断裂活动性和断裂破碎程度不同所致。对区域土壤Hg浓度(total mercury,简称为THg)与土壤气测量浓度的对比分析可知,深层THg浓度与土壤气Rn,CO_(2)和Hg浓度在空间分布上具有一定的一致性,且高值异常点分布于断裂带附近。结合区域定点前兆观测数据及地震活动性分析认为,该断裂目前活动水平相对较弱。结果表明,利用土壤气浓度的分布情况探测该区域隐伏断裂的浅层位置具有一定可行性,同时土壤气浓度连续观测对判定该区域断裂的活动性具有一定指示意义。
Two surveying lines were carried out in Haojiapo and Xiaoshuiyu of Huaizhuo basin,Hebei Province,and four periods of Rn,CO_(2)and Hg concentrations were measured.This paper studies the spatial differences of soil gas geochemical characteristics in the southwest and northeast segments of the northern margin fault of the basin and its possible relationship with fault activity. The results show that the average concentrations of soil gas Rn,CO_(2)and soil Hg in Haojiapo profile are 8 371.16 Bq/m^(3),0.85% and 14.82 ng/m^(3),respectively,and those in Xiaoshuiyu profile are 2 813.18 Bq/m^(3),0.42% and 13.08 ng/m^(3) respectively,suggesting that the former are higher than the latter. The spatial difference of concentration distribution characteristics may be caused by different fault activity and fault fragmentation degree.The comparative analyses of regional soil Hg(total mercury,Hereinafter THg) concentration and soil gas measurement concentratio show that the two contents are consistent in spatial distribution,and the high-value abnormal points are distributed near the fault zone. Combined with the regional fixed-point precursory observation data and seismicity analyses,it is considered that the current activity of the fault is relatively weak. Therefore it is feasible to detect the shallow position of concealed faults in this area by using the distribution of soil gas concentration.At the same time,continuous observation of soil gas concentration has certain indicating significance for judging the fault activity in this area.
作者
唐杰
张素欣
盛艳蕊
王江
丁志华
Tang Jie;Zhang Suxin;Sheng Yanrui;Wang Jiang;Ding Zhihua(Hebei Hongshan National Observatory on Thick Sediments and Seismic Hazards,Hebei Xingtai 055350,China;Hebei Earthquake Agency,Shijiazhuang 050021,China)
出处
《地震学报》
CSCD
北大核心
2023年第1期84-97,共14页
Acta Seismologica Sinica
基金
河北地震科技星火计划攻关项目(DZ2021121600004)
中国地震局震情跟踪定向工作任务(2021010306)
河北省地震局震情跟踪定向工作任务(202111)共同资助。
关键词
怀涿盆地北缘断裂
土壤气
土壤汞
断裂活动性
the north margin fault of Huaizhuo basin
soil gas
soil mercury
fault activity
