地震研究

昆明地震监测中心站gPhone连续重力数据DF频段信号异常变化特征与干扰分析

黄雅^1,2,韦进³,申重阳³,段毅^1,2,方伟¹

(1.云南省地震局,云南昆明 650224; 2.中国地震科学实验场大理中心,云南大理 671000; 3.中国地震局地震研究所,湖北武汉 430071)

关键词：DF频段; 视垂直位移; ASSM模型; gPhone重力仪; 台风; 地震活动

Abnormal Variation Characteristics and Interference Analysisof DF Band Signal in gPhone Continuous Gravity Dataat Kunming Earthquake Monitoring Centre Station

HUANG Ya^1,2,WEI Jin³,SHEN Chongyang³,DUAN Yi^1,2,FANG Wei¹

(1.Yunnan Earthquake Agency,Kunming 650224,Yunnan,China)(2.Dali Center of China Earthquake Science Experiment Site,Dali 671000,Yunnan,China)(3.Institute of Seismology,China Earthquake Administration,Wuhan 430071,Hubei,China)

Keywords：DF frequency; apparent vertical displacement; ASSM model; gPhone gravimeter; typhoon; seismicity

DOI: 10.20015/j.cnki.ISSN1000-0666.2025.0069

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基于2015—2020年昆明地震监测中心站(以下简称“昆明站”)的gPhone连续重力观测数据,采用时频分析方法计算双频微震(DF)频段视垂直位移,利用全球地震背景噪声能量辐射模型(ASSM)正演昆明站DF频段信号,并结合台风和邻近重力站数据,对昆明站DF频段信号异常变化特征进行研究,探讨了昆明站周边地震活动与DF频段信号之间的关系。结果显示:①年变化趋势显示昆明站周边300 km范围内M_S≥5.0地震易发生在台风频繁且DF频段视垂直位移较高的月份内,月变化趋势则显示地震易发生在视垂直位移由低转高的过程中。②2020年巧家M_S5.0地震前DF频段信号的异常变化,并不是由巧家地震引起,而与印度洋台风有关。总结震前DF频段信号异常特征,有助于该地区中强地震预测研究。

Based on gPhone continuous gravity data collected from Kunming Earthquake Monitoring Centre Station during 2015-2020,we adopted the time-frequency analysis method to calculate the apparent vertical displacement in the DF frequency band.We used the global seismic background noise energy radiation model(ASSM)to forward the DF frequency band signal at Kunming station.Referring to the data of the typhoon in the Indian Ocean,and the gravity data from the adjacent stations of Kunming station,we studied the abnormal characteristics of the DF frequency band signal at Kunming station,and explored the relationship between the earthquake activity around Kunming station and the DF frequency band signal.The results reveal that:①The annual variation trend indicates that M_S≥5.0 earthquakes around Kunming station within 300 km are prone to occuring in months with frequent typhoons and high apparent vertical displacement in the DF frequency band,while the monthly variation trend shows that earthquakes are prone to occuring during the process of the apparent vertical displacement changing from low to high.②The abnormal change of DF band signal before the Qiaojia M_S5.0 earthquake are not the precursor of the Qiaojia earthquake,but related to the typhoon from the Indian Ocean.It is helpful to predict moderate and strong earthquakes in the study area by summarizing the abnormal characteristics of DF band signal before the earthquake.

引言
1 数据与方法
2 计算结果分析
3 讨论
4 结论

图1 2015—2020年昆明站周边300 km内MS≥5.0地震分布<br/>Fig.1 Seismicity of MS≥5.0 earthquakes aroundKunming gravity station within 300 kmfrom 2015 to 2020

图1 2015—2020年昆明站周边300 km内MS≥5.0地震分布
Fig.1 Seismicity of MS≥5.0 earthquakes aroundKunming gravity station within 300 kmfrom 2015 to 2020

图2 gPhone重力仪与CTS-1地震计视垂直位移相关性分析<br/>Fig.2 Analysis of the correlation between theapparent vertical displacement from the gPhonegravimeter and the apparent vertical displacement from the CTS-1 seismometer

图2 gPhone重力仪与CTS-1地震计视垂直位移相关性分析
Fig.2 Analysis of the correlation between theapparent vertical displacement from the gPhonegravimeter and the apparent vertical displacement from the CTS-1 seismometer

图3 昆明站gPhone实际观测(a)和ASSM模型模拟(b)视垂直位移结果<br/>Fig.3 Comparison between the observed the gPhone apparent vertical displacement(a)and thesimulated apparent vertical displacement from ASSM model(b)at Kunming gravity station

图3 昆明站gPhone实际观测(a)和ASSM模型模拟(b)视垂直位移结果
Fig.3 Comparison between the observed the gPhone apparent vertical displacement(a)and thesimulated apparent vertical displacement from ASSM model(b)at Kunming gravity station

图4 2020年5月昆明站重力仪时频分析与视垂直位移变化<br/>Fig.4 Time-frequency analysis of the apparent vertical displacement and the apparentvertical displacement variation at Kunming gravity station in May 2020

图4 2020年5月昆明站重力仪时频分析与视垂直位移变化
Fig.4 Time-frequency analysis of the apparent vertical displacement and the apparentvertical displacement variation at Kunming gravity station in May 2020

图5 昆明站DF频段信号ASSM模型数值模拟结果<br/>Fig.5 Numerical simulation of the DF frequency band through ASSM model at Kunming station

图5 昆明站DF频段信号ASSM模型数值模拟结果
Fig.5 Numerical simulation of the DF frequency band through ASSM model at Kunming station

图6 腾冲站(a)、云龙站(b)、昆明站(c)gPhone重力仪和昆明站CTS-1地震计(d)观测资料时频分析结果<br/>Fig.6 Time-frequency analysis of the gravity data observed by gPhones at Tengchong station(a),Yunlong station(b),Kunming station(c)and seismic data observed by CTS-1 seismometer at Kunming station(d)

图6 腾冲站(a)、云龙站(b)、昆明站(c)gPhone重力仪和昆明站CTS-1地震计(d)观测资料时频分析结果
Fig.6 Time-frequency analysis of the gravity data observed by gPhones at Tengchong station(a),Yunlong station(b),Kunming station(c)and seismic data observed by CTS-1 seismometer at Kunming station(d)

图7 巧家MS5.0地震前后不同站点不同仪器短期视垂直位移变化特征<br/>Fig.7 Variation of short-term,apparent vertical displacement observed by instruments at some stations before and after the Qiaojia MS5.0 earthquake

图7 巧家MS5.0地震前后不同站点不同仪器短期视垂直位移变化特征
Fig.7 Variation of short-term,apparent vertical displacement observed by instruments at some stations before and after the Qiaojia MS5.0 earthquake

图8 昆明站周边300 km内MS≥5.0地震活动和视垂直位移的关系<br/>Fig.8 Relation between the seismicity of MS≥5.0 earthquakes and the apparentvertical displacement around Kunming station within 300 km

图8 昆明站周边300 km内MS≥5.0地震活动和视垂直位移的关系
Fig.8 Relation between the seismicity of MS≥5.0 earthquakes and the apparentvertical displacement around Kunming station within 300 km

图9 2015—2020年昆明站周边300 km内MS≥5.0地震发震时刻台风风向与断层走向的关系<br/>Fig.9 Relation between the wind direction of typhoon and fault's strike at the original time of theMS≥5.0 earthquakes around Kunming gravity station within 300 km from 2015 to 2020

图9 2015—2020年昆明站周边300 km内MS≥5.0地震发震时刻台风风向与断层走向的关系
Fig.9 Relation between the wind direction of typhoon and fault's strike at the original time of theMS≥5.0 earthquakes around Kunming gravity station within 300 km from 2015 to 2020