摘要
温泉水文地球化学监测可以提供很好的地震短临前兆异常信息。通过采集云南宁洱—通关火山区8个温泉出露点的水样进行水化分析,研究了温泉水文地球化学变化与地震的关系。结果表明:(1)通关火山温泉有6种水化类型,分别是Na·Ca-HCO_(3)、Na·Cl-HCO_(3)、Na-HCO_(3)、Ca-HCO_(3)、Na·Ca-SO_(4)·HCO_(3)和Na·Ca-Cl·SO_(4)型。(2)δ^(18)O和δD值分别为12.69%~-10.80‰和-89.2%~-81.5‰,表明研究区温泉水主要补给来源是大气降水,补给高程为2.0~2.7 km。(3)温泉的热储温度在81.7℃~86.3℃,热循环深度为1.1~1.3 km,其热源主要是地热增温及岩浆热。(4)2020年云南绿春M_(L)4.4地震前,清平热水塘和西萨温泉的Na^(+)、Cl^(-)、SO_(4)^(2-)浓度均出现不同幅度的升高;2021年双柏M_(S)5.2地震前,清平、西萨、厄里3个连续监测点的Na^(+)、Cl^(-)、SO_(4)^(2-)短临前兆异常响应较为明显,表现为震前5~10 d离子浓度异常升高,震后离子浓度降低至平均值上下波动。(5)短临前兆异常主要原因是震前区域构造应力场发生了变化,断裂带裂隙通透性改变,岩层渗透率增加,断裂带内的水循环发生变化,原有的水-岩反应平衡状态改变,温泉水各组分含量相应发生了变化。
The hydrogeochemial characteristics reflect information of seismic activities.In this study,eight hot spring sites in Ning’er-Tongguan volcanic area of Yunnan Province are selected for sampling and analysis.The results are as follows:(1) Volcanic hot springs in Tongguan belong to six hydrogeochemical types:Na·Ca-HCO_(3),Na·Cl-HCO_(3),Na-HCO_(3),Ca-HCO_(3),Na·Ca-SO_(4)·HCO_(3) and Na·Ca-Cl·SO_(4).(2)The oxygen and hydrogen isotopes(δ^(18)O and δD)range from 12.69‰ to-10.80‰ and-89.2‰ to-81.5‰ respectively.This indicates that the main source of the recharge for the hot springs is precipitation,and the recharge elevation ranges from 2.0 km to 2.7 km.(3) The geothermal reservoir temperature of the hot springs,calculated by the hydrogeochemical temperature scale,ranges from 52.5 ℃ to 56.4 ℃.The circulation depth of hot springs was estimated from 1.1 km to 1.3 km.The main source of heat is from geothermal gradient and magma heat.(4)Before the 2020 Luchun Earthquake,The concentration of Na^(+),Cl^(-),SO_(4)^(2-) in Qingping Hot Spring and Xisa Hot Spring rose synchronously.The Na^(+),Cl^(-),SO_(4)^(2-) ions on three monitoring sites responded to the 2021 Shuangbai Earthquake.These ions had risen 5-10 days before the Shuangbai Earthquake,then fell to the average level after the earthquake.The seismic anomaly was related to the epicentral distance and earthquake magnitude.(5)The variation of tectonic stress field increased the permeability of the stratum,and then the water in the lower aquifer mixed up with that in the upper aquifer,therefore changed the compositions of the hot-spring water.And the short-term and impending seismic precursors appeared.
作者
欧阳澍培
周晓成
何苗
天娇
李静超
董金元
李营
颜玉聪
刘峰立
姚炳宇
王昱文
曾召君
陈曲菲
罗志鑫
吉庚凤
OUYANG Shupei;ZHOU Xiaocheng;HE Miao;TIAN Jiao;LI Jingchao;DONG Jinyuan;LI Ying;YAN Yucong;LIU Fengli;YAO Bingyu;WANG Yuwen;ZENG Zhaojun;CHEN Qufei;LUO Zhixin;JI Gengfeng(United Laboratory of High Pressure Physics and Earthquake Science,Institute of Earthquake Forecasting,China Earthquake Administration,Beijing 100036,China;Economic and Technological Development Zone Brigade,Fire and Rescue Detachment of Urumqi,Fire and Rescue department of Xinjiang Uygur Autonomous Region,Urumqi 830009,Xinjiang,China)
出处
《地震研究》
CSCD
北大核心
2023年第1期37-48,共12页
Journal of Seismological Research
基金
国家重点研发计划(2017YFC1500501-05,2019YFC1509203)
国家自然科学基金面上项目(41673106,42073063,4193000170)
中国地震局地震预测研究所基本科研业务费(2021IEF0101,2021IEF1201)联合资助。
关键词
温泉
水文地球化学
前兆异常
宁洱—通关火山区
hot-spring fluids
hydrogeochemistry
earthquake precursors
the Ning’er-Tongguan volcanic area
