摘要
对2018~2020年山东及周边50个流动地磁矢量测点观测数据进行处理,得到2018-04~2019-04和2019-04~2020-04连续两期岩石圈磁场变化特征。结果表明,两期水平和垂直矢量在济南长清M4.1地震震中附近均具有较明显的局部异常特征,震前近2 a出现异常。前一期震中附近水平矢量幅值较高,近场发生转向且方向较为一致,垂直矢量幅值同样较高,在震中附近发生反转;后一期震中附近水平矢量方向汇聚,能量弱化,垂直矢量同样幅值较低,方向在震中附近发生反转。这种异常能量先强后弱特征,可能与震区应力状态的阶段性改变有关。
By processing the observation data of 50 mobile geomagnetic vector survey points in Shandong and its surrounding areas from 2018 to 2020,we obtain the variation characteristics of lithospheric magnetic field in two consecutive periods from April 2018 to April 2019 and April 2019 to April 2020.The results show that the horizontal and vertical vectors in the two periods have obvious local anomaly characteristics near the epicenter of Changqing M4.1 earthquake;the anomaly may appear nearly 2 a before the earthquake.The amplitude of horizontal vector near the epicenter of the previous period is relatively high,the direction turns in the near field and is relatively consistent,the amplitude of vertical vector is also high,and reversal occurs near the epicenter.In the later stage,the horizontal vector direction near the epicenter converges and the energy weakens,the amplitude of the vertical vector is also low,and the direction is reversed near the epicenter.The abnormal energy is first strong and then weak,which may be related to the phased change of stress state in the earthquake area.
作者
刘德强
LIU Deqiang(Hebei Hongshan National Observatory on Thick Sediments and Seismic Hazards,1540 West-Quanbei Street,Xingtai 054000,China;Mobile Survey Team of Hebei Earthquake Agency,206 Mid-Tianwei Road,Baoding 071000,China)
出处
《大地测量与地球动力学》
CSCD
北大核心
2023年第4期425-428,共4页
Journal of Geodesy and Geodynamics
基金
河北省地震科技星火计划(DZ2021121400007,DZ2021121500001)。
关键词
长清M4.1地震
岩石圈磁场
矢量异常
亚失稳
Changqing M4.1 earthquake
lithosphere magnetic field
vector anomaly
meta-stable
