震前重力场变化质源体边界和危险区划定方法研究
|
摘要
在我国大陆开展的流动重力重复观测是监测地震前兆异常的主要技术手段之一。对大地震前流动重力场观测资料研究结果表明,区域性持续的重力场增加和减少与大地震发生有显著关系。目前,区域重力场变化监测已经成为一种常规前兆观测技术手段。本文首先从三维倾斜台阶模型入手,计算了理论重力异常,并对异常进行变换,找到了一种可以更好刻画其场源边界的方法,并进一步应用空间相关系数法进行异常特征分析,得到了从概率意义上估计危险区的方法。最后,本文尝试运用此方法对青藏高原东缘地区1998—2005年的四期流动重力测网资料进行处理和分析。应用本文提出的异常处理技术,可有效地圈定异常梯级带位置,确定质源体边界形态,并可以联合背景重力异常场等其他资料,给出危险区发震概率的空间估计,分析结果在年度震情会商中可以有效地对地震危险区的划定提供技术支持。
Repeated mobile gravity observation in China mainland has been one of the main technical means for monitoring earthquake precursors.Researches on mobile observation of gravity field before large earthquakes indicated that continuous variation of regional gravity field(increase or decrease) significantly related with large earthquake occurrences.In this paper,we carried out computation and transformation of theoretical gravity anomalies based on a 3-D tilt model.We found an effective method to determine the boundaries of density anomaly source.Moreover,analysis on the characteristics of the anomalies is based on a spatial correlation coefficient method.We further obtain a probability method to estimate the hazard zone.At last,we process and analyze mobile observations of gravity in eastern margin of Tibet Plateau from 1998 to 2005 by the preceding method.It is found that the location of anomaly gradient zone and the boundary of hypocentroid can be confirmed effectively.Combined with background gravity field and other information,we can obtain a probability estimate of earthquake hazard zone,which will be necessary to determine the risk region in annual earthquake consultation.
Repeated mobile gravity observation in China mainland has been one of the main technical means for monitoring earthquake precursors.Researches on mobile observation of gravity field before large earthquakes indicated that continuous variation of regional gravity field(increase or decrease) significantly related with large earthquake occurrences.In this paper,we carried out computation and transformation of theoretical gravity anomalies based on a 3-D tilt model.We found an effective method to determine the boundaries of density anomaly source.Moreover,analysis on the characteristics of the anomalies is based on a spatial correlation coefficient method.We further obtain a probability method to estimate the hazard zone.At last,we process and analyze mobile observations of gravity in eastern margin of Tibet Plateau from 1998 to 2005 by the preceding method.It is found that the location of anomaly gradient zone and the boundary of hypocentroid can be confirmed effectively.Combined with background gravity field and other information,we can obtain a probability estimate of earthquake hazard zone,which will be necessary to determine the risk region in annual earthquake consultation.
引文
[1]陈运泰,顾浩鼎,卢造勋.1975年海城地震和1976年唐山地震前后的重力变化[J].地震学报,1980,2(1):21-31.
[2]马杏垣.重力作用与构造运动[M].北京:地震出版社,1989.
[3]Kuo J T,Sun Y F.Modeling gravity variations caused by dilatancies[J].Tectonophysics,1993,227:127-143.
[4]顾功叙,郭宗汾,刘克人,等.中国京津唐张地区时间上连续的重力变化与地震的孕育和发生[J].科学通报,1997,42(18):1 920-1 930.
[5]卢红艳,郑金涵,刘端法,等.1985-2003京津唐张地区重力变化[J].地球物理学进展,2004,19(4):887-892.
[6]郑金涵,宋胜合,刘克人,等.利用重力资料反演京津唐张地区震质中[J].地震学报,2003,25(04):422-431.
[7]Wang W Y,Pan Y,Qiu Z Y.A new edge recognition technology based on the normalized verticalderivative of the total horizontal derivative for potential field data[J].Applied Geophysics,2009,6(4):226-233.
[8]Cordell L.Gravimetric expression of graben faulting in Santa Fe Country and the Espanola Basin[M].New Mexico:New Mexico Geol.Soc.Guidebook,30th Field Conf,1979,59-64.
[9]郭仁忠.空间分析(第二版)[M].北京:高等教育出版社,2001.246-248.
[10]Clark M,Royden L H.Topographic ooze:building the eastern margin of Tibet by lower crustal flow[J].Geology,2000,28(8):703-706.
[11]杨晓松,马瑾.大陆岩石圈解耦及块体运动讨论以青藏高原—川滇地区为例[J].地学前缘,2003,10(特刊):240-247.
[12]Judith H,John H S.Uplift of the Longmen Shan and Tibetan plateau,and the 2008Wenchuan(M=7.9)earthquake[J].Nature,2009,458:194～197.
[13]李勇,徐公达,周荣军,等.龙门山均衡重力异常及其对青藏高原东缘山脉地壳隆升的约束[J].地质通报,2005,24(12):1 162-1 168.
[14]王谦身,滕吉文,张永谦,等.四川中西部地区地壳结构与重力均衡[J].地球物理学报,2009,52(2):579-583.
[15]陈石,王谦身,祝意青,等.青藏高原东缘重力导纳模型均衡异常时空特征[J].地球物理学报,2011,54(1):22-34.
[16]祝意青,王庆良,徐云马.我国流动重力监测预报发展的思考[J].国际地震动态,2008,(9):19-25.
[17]祝意青,梁伟锋,徐云马.重力资料对2008年汶川MS8.0地震的中期预测[J].国际地震动态,2008,(7):36-39.
[18]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):2 538-2 546.
[19]申重阳,李辉,孙少安.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):2 547-2 557.
[20]楼海,王椿镛,吕智勇,等.2008年汶川MS8.0地震的深部构造环境远震P波接收函数和布格重力异常的联合解释[J].中国科学D辑:地球科学,2008,38(10):1 207-1 220.
[21]王谦身,滕吉文,张永谦,等.龙门山断裂系及邻区地壳重力均衡效应与汶川地震[J].地球物理学进展,2008,23(6):1 664-1 670.
[22]滕吉文,白登海,杨辉,等.2008汶川MS8.0地震发生的深层过程和动力学响应[J].地球物理学报,2008,51(5):1 385-1 402.
[2]马杏垣.重力作用与构造运动[M].北京:地震出版社,1989.
[3]Kuo J T,Sun Y F.Modeling gravity variations caused by dilatancies[J].Tectonophysics,1993,227:127-143.
[4]顾功叙,郭宗汾,刘克人,等.中国京津唐张地区时间上连续的重力变化与地震的孕育和发生[J].科学通报,1997,42(18):1 920-1 930.
[5]卢红艳,郑金涵,刘端法,等.1985-2003京津唐张地区重力变化[J].地球物理学进展,2004,19(4):887-892.
[6]郑金涵,宋胜合,刘克人,等.利用重力资料反演京津唐张地区震质中[J].地震学报,2003,25(04):422-431.
[7]Wang W Y,Pan Y,Qiu Z Y.A new edge recognition technology based on the normalized verticalderivative of the total horizontal derivative for potential field data[J].Applied Geophysics,2009,6(4):226-233.
[8]Cordell L.Gravimetric expression of graben faulting in Santa Fe Country and the Espanola Basin[M].New Mexico:New Mexico Geol.Soc.Guidebook,30th Field Conf,1979,59-64.
[9]郭仁忠.空间分析(第二版)[M].北京:高等教育出版社,2001.246-248.
[10]Clark M,Royden L H.Topographic ooze:building the eastern margin of Tibet by lower crustal flow[J].Geology,2000,28(8):703-706.
[11]杨晓松,马瑾.大陆岩石圈解耦及块体运动讨论以青藏高原—川滇地区为例[J].地学前缘,2003,10(特刊):240-247.
[12]Judith H,John H S.Uplift of the Longmen Shan and Tibetan plateau,and the 2008Wenchuan(M=7.9)earthquake[J].Nature,2009,458:194～197.
[13]李勇,徐公达,周荣军,等.龙门山均衡重力异常及其对青藏高原东缘山脉地壳隆升的约束[J].地质通报,2005,24(12):1 162-1 168.
[14]王谦身,滕吉文,张永谦,等.四川中西部地区地壳结构与重力均衡[J].地球物理学报,2009,52(2):579-583.
[15]陈石,王谦身,祝意青,等.青藏高原东缘重力导纳模型均衡异常时空特征[J].地球物理学报,2011,54(1):22-34.
[16]祝意青,王庆良,徐云马.我国流动重力监测预报发展的思考[J].国际地震动态,2008,(9):19-25.
[17]祝意青,梁伟锋,徐云马.重力资料对2008年汶川MS8.0地震的中期预测[J].国际地震动态,2008,(7):36-39.
[18]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):2 538-2 546.
[19]申重阳,李辉,孙少安.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):2 547-2 557.
[20]楼海,王椿镛,吕智勇,等.2008年汶川MS8.0地震的深部构造环境远震P波接收函数和布格重力异常的联合解释[J].中国科学D辑:地球科学,2008,38(10):1 207-1 220.
[21]王谦身,滕吉文,张永谦,等.龙门山断裂系及邻区地壳重力均衡效应与汶川地震[J].地球物理学进展,2008,23(6):1 664-1 670.
[22]滕吉文,白登海,杨辉,等.2008汶川MS8.0地震发生的深层过程和动力学响应[J].地球物理学报,2008,51(5):1 385-1 402.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心