广西北流—广东化州5.2级地震前粤桂琼地区重力变化特征

(1. 海南省地震局,海口 570203;2.广东省地震局,广州 510070)

连续重力;流动重力;重力累积变化;重力变化异常;地震

The Characteristics of Gravity Variations in Guangdong, Guangxi and Hainan Regions before the Beiliu-Huazhou MS5.2 Earthquake in the Junction of Guangxi and Guangdong
LI Sheng1, HU Jiuchang1, LIAO Guijin2, WANG Zhicheng1, JIANG Lei1

(1.Hainan Earthquake Agency, Haikou 570203, China; 2.Guangdong Earthquake Agency, Guangzhou 510070, China)

Continuous gravity;Mobile gravity;Cumulative gravity change;Abnormal gravity change; Earthquake

DOI: 10.13512/j.hndz.2020.02.08

备注

收集了粤桂琼地区4个台站的连续重力观测资料和雷琼地区的流动重力观测资料,研究了广西北流—广东化州5.2级地震前粤桂琼地区重力变化特征。其中连续重力观测资料的分析从重力扰动和重力M2波潮汐因子变化两个方面进行;流动重力观测资料的分析从重力场差分动态和累积动态变化两个方面进行。连续重力观测资料的研究表明震前粤桂琼地区连续重力观测资料无异常现象;雷琼地区流动重力观测资料的研究结果表明,广西北流—广东化州5.2级地震前,震中附近地区存在重力场变化异常,异常持续时间约2年,异常范围约100km,异常量级约50x10-8m·s-2,地震发生于重力场变化的高梯度带上。

This paper collected the continuous gravity observation data of 4 seismic stations in Guangdong, Guangxi and Hainan, and mobile gravity observation data in Leizhou-Hainan area, and studied the characteristics of gravity changes in the Guangdong, Guangxi and Hainan area before the Beiliu-Huazhou MS5.2 Earthquake. The analysis of continuous gravity observation data is carried out from two aspects of the gravity disturbance and the tide factor change of gravity M2 wave. The analysis of mobile gravity observation data is carried out from two aspects of the differential dynamics and cumulative dynamics of gravity field. The study of continuous gravity observation data shows that the continuous gravity observation data don’t have abnormal. The results of the mobile gravity data in Leizhou-Hainan show that before the Beiliu-Huazhou MS5.2 earthquake, there was an abnormal change in the gravity field near the epicenter. The anomaly lasted about 2 years,of which the range was about 100 km and the magnitude was about 50x10-8m·s-2, and the earthquake occurred on the high gradient zone of gravity field change.