甘东南重力、b值异常与岷县—漳县M6.6地震关系探讨
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摘要
利用甘东南测网2010—2014年的流动重力观测数据,分析2013年7月22日甘肃岷县—漳县M6.6地震前后1a尺度的重力场变化,并结合地震b值图像和GNSS结果进一步分析甘东南重力、b值异常与岷县—漳县M6.6地震的关系,结果表明:(1)测区重力异常经历了由"区域重力负值变化→持续负值变化→转折上升正变化—发震→震后恢复变化"的时空演化过程;(2)岷县—漳县M6.6地震前后b值曲线出现"低值—高值—回落发震"的变化特征;(3)岷县—漳县M6.6地震发生在重力变化高梯度带上、"0"等值线附近和低b值区域。
In this paper,the gravity changes of one year scale before and after the Minxian—Zhangxian M6.6 earthquake on July 22,2013 are analyzed using the mobile gravity observation data from 2010 to 2014 in southeast Gansu network,and then the relationship between the gravity and b-value anomalies in southeast Gansu and the Minxian—Zhangxian M6.6 earthquake is discussed considering the b-value image and global navigation satellite systems result.The results indicate the following:(1)The gravity anomaly in the study area underwent a spatiotemporal evolution from regional negative gravity change to constant negative change,positive change of turn and increase,earthquake occurrence,and then recovery after the earthquake;(2)before and after the Minxian—Zhangxian M6.6 earthquake,the b-value curve shows characteristics of low value-high value-reduction and shock;(3)the Minxian—Zhangxian M6.6 earthquake occurred ina high gradient zone of gravity change near the "0" contour line and the lowb-value region.
In this paper,the gravity changes of one year scale before and after the Minxian—Zhangxian M6.6 earthquake on July 22,2013 are analyzed using the mobile gravity observation data from 2010 to 2014 in southeast Gansu network,and then the relationship between the gravity and b-value anomalies in southeast Gansu and the Minxian—Zhangxian M6.6 earthquake is discussed considering the b-value image and global navigation satellite systems result.The results indicate the following:(1)The gravity anomaly in the study area underwent a spatiotemporal evolution from regional negative gravity change to constant negative change,positive change of turn and increase,earthquake occurrence,and then recovery after the earthquake;(2)before and after the Minxian—Zhangxian M6.6 earthquake,the b-value curve shows characteristics of low value-high value-reduction and shock;(3)the Minxian—Zhangxian M6.6 earthquake occurred ina high gradient zone of gravity change near the "0" contour line and the lowb-value region.
引文
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[12]郝洪涛,李辉,张志坚.岷县—漳县6.6级地震前后重力场变化[J].大地测量与地球动力学,2014,34(3):43-47.HAO Hongtao,LI Hui,ZHANG Zhijian.Variation of Gravity-field Before and after Minxian—Zhangxian MS6.6Earthquake[J].Journal of Geodesy and Geodynamics,2014,34(3):43-47.
[13]冯建刚,张辉,杨萍.2013年甘肃岷县漳县6.6级地震前地震b值异常特征研究[J].中国地震,2016,36(1):32-36.FENG Jiangang,ZHANG Hui,YANG Ping.Analysis on Earthquake b-value Abnormity of the Gansu Minxian—Zhangxian MS6.6 Earthquake in 2013[J].Earthquake Research in China,2016,36(1):32-36.
[14]梁伟锋,刘芳,祝意青,等.重力仪一次项系数对重力场动态变化的影响研究[J].大地测量与地球动力学,2015,35(5):882-886.LIANG Weifeng,LIU Fang,ZHU Yiqing,et al.Research on the Effect of One Degree Term of Chromatic Polynomial of Gravimeter on Gravity Dynamic Change[J].Journal of Geodesy and Geodynamics,2015,35(5):882-886.
[15]SCHOLZ C H.The Frequency-magnitude Relation to Microfracturing in Rock and Its Relation to Earthquakes[J].Bull Seism Soc Am,1968,58:399-415.
[16]梅世蓉,冯德益,张国民,等.中国地震预报概论[M].北京:地震出版社,1993.MEI Shirong,FENG Deyi,ZHANG Guomin,et al.Introduction to Earthquake Prediction in China[M].Beijing:Seismological Press,1993.
[17]郑文俊,袁道阳,何文贵,等.甘肃东南地区构造活动与2013年岷县—漳县MS6.6级地震孕震机制[J].地球物理学报,2013,56(12):4058-4071.ZHENG Wenjun,YUAN Daoyang,HE Wengui,et al.Geometric Pattern and Active Tectonics in Southeastern Gansu Province:Discussion on Seismogenic Mechanism of the Minxian—Zhangxian MS6.6Earthquake on July 22,2013[J].Chinese J Geophysics,2013,56(12):4058-4071.
[18]祝意青,李铁明,郝明,等.2016年青海门源MS6.4地震前重力变化[J].地球物理学报,2016,59(10):3744-3752.ZHU Yiqing,LI Tieming,HAO Ming,et al.Gravity Changes Before the Menyuan,Qinghai MS6.4Earthquake of 2016[J].Chinese J Geophysics,2016,59(10):3744-3752.
[2]邓起东.关于四川汶川8.0级地震的思考[J].地震地质,2008,30(4):811-823.DENG Qidong.Some Thoughts on the MS8.0 Wenchuan,Sichuan Earthquake[J].Seismology and Geology,2008,37(1):319-328.
[3]张培震,徐锡伟,闻学泽,等.2008年汶川8.0级地震发震断裂的滑动速率、复发周期和构造成因[J]地球物理学报,2008,51(4):1066-1073.ZHANG Peizhen,XU Xiwei,WEN Xueze,et al.Slip Rates and Recurrence Intervals of the Longmenshan Active Fault Zone,and Tectonic Implications for the Mechanism of the May 12Wenchuan Earthquake,2008,Sichuan,China[J].Chinese J Geophysics,2008,51(4):1066-1073.
[4]陈运泰,杨智娴,张勇,等.从汶川地震到芦山地震[J].中国科学,2013,43(6):1064-1072.CHEN Yuntai,YANG Zhixian,ZHANG Yong,et al.From2008 Wenchuan Earthquake to 2013Lushan Earthquake[J].Chinese J Geophysics,2013,43(6):1064-1072.
[5]祝意青,徐云马,吕弋培,等.龙门山断裂带重力变化与汶川8.0级地震关系研究[J].地球物理学报,2009,52(10):2538-2546.ZHU Yiqing,XU Yunma,LYipei,et al.Relations Beween Gravity Variation of Longmenshan Fault Zone and Wenchuan MS8.0Earthquakes[J].Chinese J Geophysics,2009,52(10):2538-2546.
[6]申重阳,李辉,孙少安,等.重力场动态变化与汶川MS8.0地震孕育过程[J].地球物理学报,2009,52(10):2547-2557.SHEN Chongyang,LI Hui,SUN Shaoan,et al.Dynamic Variations of Gravity and the Preperation Process of the Wenchuan MS8.0Earthquake[J].Chinese J Geophysics,2009,52(10):2547-2557.
[7]梁伟锋,刘芳,徐去马,等.青藏高原东缘重力观测及对芦山M7.0地震的反映[J].地震工程学报,2013,35(2):266-270.LIANG Weifeng,LIU Fang,XQuma,et al.Gravity Observation in the Eastern Margin of Qinghai—Tibetan Plateau and Reflect to the Lunshan M7.0Earthquake[J].China Earthquake Engineering Journal,2013,35(2):266-270.
[8]祝意青,付广裕,梁伟锋,等.鲁甸MS6.5、芦山MS7.0、汶川MS8.0地震前区域重力场时变[J].地震地质,2015,37(1):319-328.ZHU Yiqing,FU Gangyu,LIANG Weifeng,et al.Earthquake Predictions:Spatial-temporal Gravity Changes Before the Ludian MS6.5,Lushan MS7.0and Wenchuan MS8.0Earthquakes[J].Seismology and Geology,2015,37(1):319-328.
[9]刘艳辉,赵根模,吴中海,等.青藏高原东南缘及邻区近年来地震b值特征[J].地质通报,2015,34(1):1756-1765.LIU Yanhui,ZHAO Genmo,WU Zhonghai,et al.An Analysis of b-value Characteristics of Earthquake on the Southeastern Magin of the Tibetan Plateau and Its Neighboring Areas[J].Geological Bulletin of China,2015,34(1):1756-1765.
[10]祝意青,刘芳,郭树松.2010年玉树MS7.1地震前的重力变化[J].大地测量与地球动力学,2011,31(1):1-4.ZHU Yiqing,LIU Fang,GUO Shusong.Gravity Changes Before Yushu MS7.0Earthquake[J].Journal of Geodesy and Geodynamics,2011,31(1):1-4.
[11]祝意青,赵云峰,李铁明,等.2013年甘肃岷县漳县6.6级地震前后重力场动态变化[J].地震地质,2014,36(3):667-674.ZHU Yiqing,ZHAO Yunfeng,LI Tieming,et al.Dynamic Variation of Gravity Field Before and after the Minxian—Zhangxian MS6.6Earthquake[J].Seismology and Geology,2014,36(3):667-674.
[12]郝洪涛,李辉,张志坚.岷县—漳县6.6级地震前后重力场变化[J].大地测量与地球动力学,2014,34(3):43-47.HAO Hongtao,LI Hui,ZHANG Zhijian.Variation of Gravity-field Before and after Minxian—Zhangxian MS6.6Earthquake[J].Journal of Geodesy and Geodynamics,2014,34(3):43-47.
[13]冯建刚,张辉,杨萍.2013年甘肃岷县漳县6.6级地震前地震b值异常特征研究[J].中国地震,2016,36(1):32-36.FENG Jiangang,ZHANG Hui,YANG Ping.Analysis on Earthquake b-value Abnormity of the Gansu Minxian—Zhangxian MS6.6 Earthquake in 2013[J].Earthquake Research in China,2016,36(1):32-36.
[14]梁伟锋,刘芳,祝意青,等.重力仪一次项系数对重力场动态变化的影响研究[J].大地测量与地球动力学,2015,35(5):882-886.LIANG Weifeng,LIU Fang,ZHU Yiqing,et al.Research on the Effect of One Degree Term of Chromatic Polynomial of Gravimeter on Gravity Dynamic Change[J].Journal of Geodesy and Geodynamics,2015,35(5):882-886.
[15]SCHOLZ C H.The Frequency-magnitude Relation to Microfracturing in Rock and Its Relation to Earthquakes[J].Bull Seism Soc Am,1968,58:399-415.
[16]梅世蓉,冯德益,张国民,等.中国地震预报概论[M].北京:地震出版社,1993.MEI Shirong,FENG Deyi,ZHANG Guomin,et al.Introduction to Earthquake Prediction in China[M].Beijing:Seismological Press,1993.
[17]郑文俊,袁道阳,何文贵,等.甘肃东南地区构造活动与2013年岷县—漳县MS6.6级地震孕震机制[J].地球物理学报,2013,56(12):4058-4071.ZHENG Wenjun,YUAN Daoyang,HE Wengui,et al.Geometric Pattern and Active Tectonics in Southeastern Gansu Province:Discussion on Seismogenic Mechanism of the Minxian—Zhangxian MS6.6Earthquake on July 22,2013[J].Chinese J Geophysics,2013,56(12):4058-4071.
[18]祝意青,李铁明,郝明,等.2016年青海门源MS6.4地震前重力变化[J].地球物理学报,2016,59(10):3744-3752.ZHU Yiqing,LI Tieming,HAO Ming,et al.Gravity Changes Before the Menyuan,Qinghai MS6.4Earthquake of 2016[J].Chinese J Geophysics,2016,59(10):3744-3752.