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Title:: Analysis of Gravity Field Change and Index Quantity in Southern Part of the South-North Seismic Belt

Author(s):: CHEN Zhaohui; WANG Tongqing; LIU Jinzhao; ZHU Chuandong; ZHANG Pin; ZHANG Shuangxi; (The First Monitoring and Application Center,China Earthquake Administration,Tianjin 300180,China)

摘要:: 利用2014—2017年南北地震带南段流动重力观测资料,基于重力段差值的重力场可视化方法和显著性指标量G值和C值,对南北地震带南段重力场变化特征和地震孕育之间的关系做初步的探讨和分析。结果表明:(1)研究区近期4.5级以上地震多发生在重力场变化的正、负异常过渡带和高梯度带附近,与深部物质运移的复杂动力学过程、地壳运动和断裂活动具有一定的关系;(2)指标量G值和C值作为评价测网重力场变化显著性异常程度的定量依据,反映了研究区同一时间段内地震活动和未来潜在强震的综合效应,对于深入判定潜在地震危险性具有一定的参考价值。

Abstract:: By deeply processing the mobile gravity data of the southern part of the South-North Seismic Belt from 2014 to 2017,this paper makes a preliminary discussion and analysis on the relationship between gravity field change and earthquake preparation in the study area with the gravity field visualization method based on the gravity segment difference and the significant index G and C.These results show that(1)the recent earthquakes with M_S4.5+ in the study area always occur near the positive and negative anomalous transition zone and the high gradient zone,which is related to the complex dynamical process of deep matter migration,the crustal movement and the fault activity.(2)The quantity of G and C is useful for quantitative evaluation of the gravity anomaly degree,reflecting the combined effects of seismic activity within the same time period and potential strong earthquakes,which is of great scientific significance for the further determination of potential seismic risk region.