地震研究

四川理塘毛垭51泉水温在青藏高原东南缘中强地震前的异常特征及机理分析

(1.四川省地震局,四川成都 610041; 2.成都理工大学地球科学学院,四川成都 610041; 3.甘孜州应急管理局,四川康定 626099)

Anomaly Characteristics of the Water Temperature of Maoya,Litang 51th Spring before the Mid-strong Earthquakes in the Southeastern Tibetan Plateau and Its Precursor Mechanisms

RUI Xuelian¹,YANG Yao^1,2,GUAN Zhijun¹,DU Fang¹,XUE Qiaowen³,LONG Feng¹,YANG Xing¹,YANG Peng¹

(1.Sichuan Earthquake Agency,Chengdu 610041,Sichuan,China)(2.College of Earth Science,Chengdu University of Technology,Chengdu 610041,Sichuan,China)(3.Ganzi Prefecture Emergency Management Agency,Kangding 626099,Sichuan,China)

Keywords：Maoya,Litang 51th hot spring; water temperature anomaly; the Yangbi M_S6.4 earthquake; the Litang Fault Zone

DOI: 10.20015/j.cnki.ISSN1000-0666.2022.0040

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参考文献

采用四川理塘毛垭51泉46年的人工观测水温数据,结合区域水文地质、水文地球化学、气象等资料,分析了水温的基本动态特征、水温异常的映震特征及其在漾濞MS6.4地震前的异常变化,并初步讨论了异常机理。结果表明:理塘毛垭51泉水温在不同背景温度下的震前水温上升幅度指标存在差异,2009年以来温泉变为低温温泉,水温上升异常阈值由原8 ℃降低为6 ℃。理塘毛垭51泉具有深循环特征,且处于构造交汇部位,水温异常变化能够反映地壳深度热流和构造活动信息,对青藏高原东南缘中强震具有较好的预测效能,优势预测区域为川滇交界西侧。

Based on the temperature observation data of the water in Maoya,Litang spring over the 46 years,we analyze temperature dynamic variation characteristics of Maoya,Litang spring,and anomaly characteristics before the Yangbi MS6.4 earthquake combined with regional hydrogeology,hydrogeochemistry,meteorology data.Further on,we discuss the probable anomaly mechanism of the spring water.The results show that there are differences in the amplitude of temperature anomaly at different background temperatures.Since 2009,the hot spring has changed from a medium-high temperature to a low-temperature one,and the abnormal threshold has been reduced from the original 8 ℃ to 6 ℃.The Maoya spring is located at the junction of three active faults belonging to the Litang Fault Zone and it is characterized by deep circulation,thus spring's temperature can reflect deep crustal or mantel fluid information and is sensitive to the regional tectonic activity related to earthquakes.The observed temperature of this spring shows abnormal characteristics before mid-strong earthquakes which occurred in the southeastern Tibetan Plateau,and the dominant earthquake-prone area is the southwestern part of the Sichuan-Yunnan Block.

引言
1 构造背景
2 水温历史资料分析
3 数据处理及异常提取
4 水温异常特征分析
5 结论

图1 研究区域大地构造背景(a)与观测点(b)示意图<br/>Fig.1 The schematic diagram of tectonic settingas(a)and observation station(b)in the study area

图1 研究区域大地构造背景(a)与观测点(b)示意图
Fig.1 The schematic diagram of tectonic settingas(a)and observation station(b)in the study area

图2 理塘毛垭51泉测点地质构造图(据郑裕民,1984; 龙德雄等,2006)<br/>Fig.2 Geological structure map of Maoya,Litang 51th spring area(based on Zheng,1984; Long et al,2006)

图2 理塘毛垭51泉测点地质构造图(据郑裕民,1984; 龙德雄等,2006)
Fig.2 Geological structure map of Maoya,Litang 51th spring area(based on Zheng,1984; Long et al,2006)

图3 理塘毛垭51泉水温月均值时序曲线(a)及水温特征统计(b)<br/>Fig.3 Monthly mean values(a)and statistical graph(b)of the water temperature of Maoya,Litang 51th spring

图3 理塘毛垭51泉水温月均值时序曲线(a)及水温特征统计(b)
Fig.3 Monthly mean values(a)and statistical graph(b)of the water temperature of Maoya,Litang 51th spring

图4 理塘毛垭51泉水温一阶差分结果<br/>Fig.4 The first-order difference graph of the water temperature of Maoya,Litang 51th spring

图4 理塘毛垭51泉水温一阶差分结果
Fig.4 The first-order difference graph of the water temperature of Maoya,Litang 51th spring

表1 理塘毛垭51泉水温异常及对应地震统计<br/>Tab.1 Temperature anomalies of Maoya,Litang 51th spring and the corresponding earthquakes

表1 理塘毛垭51泉水温异常及对应地震统计
Tab.1 Temperature anomalies of Maoya,Litang 51th spring and the corresponding earthquakes

图5 不同时段内理塘毛垭51泉水温异常与地震对应关系图<br/>Fig.5 Temperature anomalies of Maoya,Litang 51th spring and the corresponding earthquakes during different periods

图5 不同时段内理塘毛垭51泉水温异常与地震对应关系图
Fig.5 Temperature anomalies of Maoya,Litang 51th spring and the corresponding earthquakes during different periods

图6 理塘毛垭51泉水温异常对应MS≥5.5地震空间分布<br/>Fig.6 Location of Maoya,Litang 51th spring and spatial distribution of earthquakes associated with temperature anomalies

图6 理塘毛垭51泉水温异常对应MS≥5.5地震空间分布
Fig.6 Location of Maoya,Litang 51th spring and spatial distribution of earthquakes associated with temperature anomalies

图7 2020-01—2021-10理塘毛垭51泉水温差分曲线<br/>Fig.7 The first-order difference graph of Maoya,Litang 51th spring from Jan., 2020 to Oct.,2021

图7 2020-01—2021-10理塘毛垭51泉水温差分曲线
Fig.7 The first-order difference graph of Maoya,Litang 51th spring from Jan., 2020 to Oct.,2021

图8 2018-01—2021-10气温(a)、水温(b)观测曲线日值<br/>Fig.8 Daily curves of air temperature(a)and water temperature(b)from Jan.,2018 to Oct.,2021

图8 2018-01—2021-10气温(a)、水温(b)观测曲线日值
Fig.8 Daily curves of air temperature(a)and water temperature(b)from Jan.,2018 to Oct.,2021

表2 理塘毛垭51泉及附近水体水化学成分及同位素分析结果<br/>Tab.2 Chemical compositions and isotopes of the water samples of Maoya,Litang 51th spring and rivers

表2 理塘毛垭51泉及附近水体水化学成分及同位素分析结果
Tab.2 Chemical compositions and isotopes of the water samples of Maoya,Litang 51th spring and rivers

图9 理塘毛垭51泉及河水水样测试结果分析图<br/>Fig.9 Chemical test of groundwater samples from Maoya,Litang 51th spring and rivers

图9 理塘毛垭51泉及河水水样测试结果分析图
Fig.9 Chemical test of groundwater samples from Maoya,Litang 51th spring and rivers

图10 研究区(蓝色矩形框)和青藏高原东缘构造环境及GPS速度场示意图(据Zhang et al,2004; Shen et al,2005; 邓起东等,2007; Hao et al,2019; 瞿伟等,2021修改)<br/>Fig.10 Schematic diagram of tectonic environment and GPS velocity field in the study area(blue rectangle) and the eastern edge of the Qinghai-Tibet Plateau (according to Zhang et al,2004; Shen et al, 2005; Deng et al,2007; Hao et al, 2019; Qu et al,2021)

图10 研究区(蓝色矩形框)和青藏高原东缘构造环境及GPS速度场示意图(据Zhang et al,2004; Shen et al,2005; 邓起东等,2007; Hao et al,2019; 瞿伟等,2021修改)
Fig.10 Schematic diagram of tectonic environment and GPS velocity field in the study area(blue rectangle) and the eastern edge of the Qinghai-Tibet Plateau (according to Zhang et al,2004; Shen et al, 2005; Deng et al,2007; Hao et al, 2019; Qu et al,2021)