地震重力分析是指,通过研究时变重力场变化,进而获取地球内部介质物性变化信息。本文选取川滇地区2013—2017年流动重力观测资料,采用欧拉反褶积方法,对研究区重力变化场源深度及空间分布特征进行反演和解释,分析研究区重力观测网总体监测能力。以2014年鲁甸MS 6.5地震为例,通过反演计算研究区重力场差分变化,发现重合度较好地区集中在鲁甸以南垂直于昭通断裂的NW向条带状区域,整体场源深度集中分布在20—40 km范围内,与此次鲁甸地震序列主震和余震深度分布范围相对应,重力变化且集中在断裂带附近。研究结果可为进一步研究川滇地区深部孕震环境特征提供一定参考。
Seismic gravity analysis refers to acquiring information on the physical properties of the Earth’s internal medium by studying the changes in the time-varying gravity field. This paper selects the mobile gravity observation data of the Sichuan-Yunnan region from 2013 to 2017 and uses the Euler deconvolution method to invert and interpret the source depth and spatial distribution characteristics of the gravity change field in the study area to analyze the overall monitoring capability of the gravity observation network in the study area. Taking the Ludian MS 6.5 earthquake in 2014 as an example, the differential changes in the gravity field in the study area are calculated through inversion. It is found that the areas with good coincidence are concentrated in the NW-trending strip-shaped area south of Ludian, perpendicular to the Zhaotong Fault. The overall source depth is concentrated in the range of 20-40 km, which corresponds to the depth distribution range of the main shock and aftershocks of this Ludian earthquake sequence. The gravity changes are concentrated near the fault zone. The research results can provide a certain reference for further studying the deep seismogenic environment characteristics of the Sichuan-Yunnan region.
2025,46(1): 13-19 收稿日期:2024-9-19
DOI:10.3969/j.issn.1003-3246.2025.01.002
基金项目:中国地震局第一监测中心科技创新主任基金(项目编号:XH21030Y);中国地震局震情跟踪项目(项目编号:2024020203)
作者简介:程程(1996—),女,硕士研究生,助理工程师,主要从事地球物理资料分析与地震预测工作。E-mail:767795897@qq.com
参考文献:
陈运泰,顾浩鼎,卢造勋. 1975年海城地震与1976年唐山地震前后的重力变化[J]. 地震学报,1980,2(1):21-31.
焦新华,吴燕冈. 重力与磁法勘探[M]. 北京:地震出版社,2009.
祝意青,闻学泽,孙和平,等. 2013年四川芦山MS 7.0地震前的重力变化[J]. 地球物理学报,2013,56(6):1 887-1 894.
王同庆,陈石,梁伟锋,等. 2016年门源MS 6.4地震前的区域重力场变化与定量参数分析[J].地震地质,2018,40(2):349-360.
张双喜,陈超,王林松,等. 二维经验模态分解及其在位场去噪和分离中的应用[J].地球物理学进展,2015,30(6):2 855-2 862.
张双喜,陈兆辉,王青华,等. 利用小波变换提取川滇地区流动重力异常特征-以2014年鲁甸MS 6.5、景谷MS 6.6地震为例[J]. 大地测量与地球动力学,2020,40(1):87-93.
刘芳,祝意青,陈石. 华北时变重力场离散小波多尺度分解[J]. 中国地震,2013,29(1):124-131.
徐伟民,陈石,阮明明,等. 川滇地区陆地流动重力测网场源分辨能力评估[J]. 地震,2021,41(1):191-204.
范美宁. 欧拉反褶积放阀的研究与应用[D]. 长春:吉林大学,2006:12-25.
高倩,陈石. 基于欧拉反褶积方法计算川滇交界重力变化场源特征[J]. 地球物理学进展,2015,30(2):503-509.
刘芳,祝意青,梁伟锋,等. 基于欧拉反褶积方法估算华北地区重力变化的等效源参数[J]. 地震,2016,4(36):163-170.
祝意青,刘芳,李铁明,等.川滇地区重力场动态变化及其强震危险含义[J]. 地球物理学报,2015,58(11):4 187-4 196.
张培震,邓起东,张国民,等. 中国大陆的强震活动与活动地块[J]. 中国科学:地球科学,2003,33(Z1):12-20.
付广裕,孙文科. 地球横向不均匀结构对地表以及空间固定点同震重力变化的影响[J]. 地球物理学报,2012,55(8):2 728-2 746.
陈石,王谦身,祝意青,等. 汶川MS 8.0震前区域重力场变化与震质中研究[J].地球物理学进展,2011,26(4):1 147-1 156.
陈石,王青华,王谦身,等. 云南鲁甸MS 6.5地震震源区和周边三维密度结构及重力场变化[J].地球物理学报,2014,57(9):3 080-3 090.
贾晓东,翟丽娜,陈石. 辽宁地区时变重力场源变化特征分析[J]. 地震,2021,41(1):180-190.
翟丽娜,贾晓东,焦明若,等. 辽宁地区时变重力场源变化特征分析[J]. 地震研究,2020,43(2):388-393+418.
李大虎,丁志峰,梁明剑,等. 四川地区流动重力资料的位场分离与异常特征提取[J]. 地震学报,2014,36(2):261-274.
郭树松,刘芳,祝意青. 小波多尺度分解在地震预测中的应用[J]. 大地测量与地球动力学,2014,34(4):34-38.
Chen S, Jiang C S, Zhuang J C. Statistical evaluation of efficiency and possibility of earthquake predictions with gravity field variations and its analytic signal in western china[J]. Pure and Applied Geophysics, 2016, 173(1): 305-319.
Chen Y T, Gu H D, Lu Z X. Variations of gravity before and after the Haicheng earthquake, 1975, and the Tangshan earthquake, 1976[J]. Physics of the Earth and Planetary Interiors, 1979, 18(4): 330-338.
Kuo J T, Zheng J H, Song S H. Determination of earthquake epicentroids by inversion of gravity variation data in the BTTZ region, China[J]. Tectonophysics, 1999, 312(2): 267-281.
Reid A B, Allsop J M, Granser H, et al. Magnetic interpretation in three dimension using Euler deconvolution[J]. Geophysics, 1990, 55: 80-91.
Thompson D T. Anew technique for making computer-assisted depth estimates from magnetic data[J]. Geophysics, 1982, 47: 32-38.
Zhu Y Q, Liang W F, Zhang S. Earthquake precursors: spatial-temporal gravity changes before the great earthquakes in the Sichuan-Yunnan area[J]. Journal of Seismology, 2017.
Zhu Y, Zhan F B, Zhou J, et al. Gravity measurements and their variations before the 2008 Wenchuan eathquake[J]. Bull Seismol Soc Am, 2010, 100(5B): 2 815-2 824.
Zhu Y, Zhan F B, Zhou J, et al. Gravity measurements and their variations before the 2008 Wenchuan eathquake[J]. Bull Seismol Soc Am, 2010, 100(5B): 2 815-2 824.