摘要
土壤气氡作为断层活动性分析与隐伏断层识别的有效指标,在构造地球化学研究中具有重要价值。本文基于2024年9月山东安丘—莒县断裂10条测线104个测点的土壤气氡数据,通过统计分析、多维度对比及机理探讨,揭示其地球化学特征及构造指示意义。结果表明,该断裂带土壤气氡浓度范围为1930~74300Bq/m^(3),整体呈“北高南低”分布,主体接近正态分布,但含断层裂隙导致的极端高值;测线曲线形态多样,单峰对应单一断层位置,双峰/多峰反映多段氡气富集区,与断裂及褶皱裂隙特征一致。分段来看,北段(昌邑、坊子、安丘)背景值(33072Bq/m^(3))显著高于南段(11663Bq/m^(3)),南段极值比(3.16)高于北段(2.25),表明北段整体裂隙更发育,南段局部应力集中更明显。土壤气氡与CO_(2)、H_(2)的背景值分布趋势高度一致,与2017年数据对比,显示郯城段极值比上升,可能指示应力增强。研究认为,氡分布受地质构造(地层、断裂产状)、地震活动性(南段地震频发)及气象因素(降雨量)共同影响,其特征可为安丘—莒县断裂活动性评价与地震风险评估提供关键地球化学依据。
Soil gas radon is a valuable indicator for assessing fault activity and identifying concealed faults,making it an important tool in tectonogeochemical research. This study analyzes soil gas radon data collected in September 2024 from 104 measuring points along 10 survey lines in the Anqiu-Juxian fault zone,Shandong Province,to reveal its geochemical characteristics and tectonic implications through statistical analysis,multi-dimensional comparison,and mechanistic interpretation. Results show that radon concentrations range from 1930 to 74300Bq/m^(3),displaying a general “north-high,south-low” spatial pattern. The overall distribution approximates normality but contains extreme values associated with faults. Survey line profiles exhibit diverse morphologies:single peaks correspond to individual faults,whereas double or multiple peaks reflect multi-segment radon enrichment zones,consistent with fault and fold structures. In terms of segmentation,the northern section(Changyi-Fangzi-Anqiu)shows a higher background value(33072Bq/m^(3))than the southern section(11663Bq/m^(3)),while the southern section displays a higher extreme-value ratio(3. 16 vs. 2. 25),suggesting that the north is characterized by more developed fractures,whereas the south exhibits stronger localized stress concentration. The spatial distributions of radon,CO_(2),and H_(2) are highly consistent. Comparison with 2017 data reveals an increase in the extreme-value ratio in the Tancheng segment,potentially indicating elevated stress. Overall,the results suggest that radon distribution is controlled by geological structures(strata and fault geometry),seismic activity(frequent earthquakes in the southern section),and meteorological conditions(rainfall). These findings provide important geochemical evidence for evaluating fault activity and seismic risk in the Anqiu-Juxian fault zone.
作者
郑家军
董敏
陈其峰
曹一
冯粱乐
杨立涛
韩博
丁欣
熊玮
李小晗
Zheng Jiajun;Dong Min;Chen Qifeng;Cao Yi;Feng Liangle;Yang Litao;Han Bo;Ding Xin;Xiong Wei;Li Xiaohan(Weifang Earthquake Monitoring Center Station,Shandong Earthquake Agency,Weifang 261041,Shandong,China;Liaocheng Earthquake Monitoring Center Station,Shandong Earthquake Agency,Liaocheng 252000,Shandong,China;Heze Earthquake Monitoring Center Station,Shandong Earthquake Agency,Heze 274000,Shandong,China;Shandong Earthquake Agency,Jinan 250102,China)
出处
《中国地震》
北大核心
2025年第3期476-490,共15页
Earthquake Research in China
基金
山东省地矿局海岸带地质环境保护重点实验室
潍坊市海岸带地下水及地质环境保护与修复重点实验室开放基金项目,山东郯城巨震区低速率挤压逆冲构造野外科学观测研究站,山东省地震局震情跟踪任务(2024),山东省地震局科研项目(YB2323、YB2327)共同资助。
关键词
土壤气氡
安丘—莒县断裂
地球化学特征
断层活动性
构造指示
Soil gas Radon
Anqiu-Juxian Fault
Geochemical characteristics
Fault activity
Tectonic indication
