高频GPS监测的阿拉斯加地震同震形变与震级预估
Coseismic deformation characteristics and magnitude estimation of Alaska earthquake observed by high-frequency GPS
李波 1高志钰 2曾致 3李亚芳 1李金香1
作者信息
- 1. 新疆维吾尔自治区地震局, 乌鲁木齐 830011
- 2. 中国地震局地质研究所 地震动力学国家重点实验室, 北京 100029;兰州交通大学 测绘与地理信息学院, 兰州 730070
- 3. 西安市勘察测绘院, 西安 710054
- 折叠
摘要
为了进一步研究 2020 年阿拉斯加矩震级(MW)7.8 地震同震形变获取及震级预估,提出一种高频全球定位系统(GPS)监测的阿拉斯加地震同震形变与震级预估方法:利用双差动态定位方法处理震中周边 9 个高频GPS测站数据,并解算得到这些测站的三维位移波形;最后获取此次地震引起的同震形变并对震级结果进行预估分析.结果表明,近场GPS 测站位移波形变化幅度显著,波动幅度变化不仅受震中距的影响,也可能受破裂断层、地震波传播路径及场地效应等的影响;距震中最近的AC12 测站水平地面峰值位移约为 40 cm,永久水平位移约为 24 cm,垂向抬升约 30.6 cm,震中140 km范围内的GPS测站均能够监测到量值大于 1 cm的永久水平形变,330 km范围内的GPS测站能够监测到毫米级以上的永久水平形变,除AC12 测站与AC45 测站外,此次地震造成其余测站明显的永久沉降.这些结果反映出此次地震的震源特征表现为逆冲性质,也可为后续的研究工作提供参考;利用这些高频 GPS地面峰值位移(PGD)预估此次地震的震级为 7.78,与实际震级基本一致,表明利用高频GPS数据进行强震震级快速预估的可靠性.
Abstract
In order to further study the acquisition of the coseismic deformation and the prediction of the magnitude for the 2020 Alaska moment magnitude scale(Mw)7.8 earthquake,the paper proposed a method of coseismic deformation characteristics analysis and magnitude estimation of Alaska earthquake observed by high-frequency GPS:a double difference dynamic positioning method was used to process the data of nine high-frequency global positioning system(GPS)stations around the epicenter,and the three-dimensional displacement waveforms of these stations were calculated;finallly,the coseismic deformation caused by this earthquake was obtained and the magnitude results were predicted and analyzed.Results showed that the displacement waveforms of near-field GPS stations would change significantly,and the fluctuation amplitude change could be affected not only by the epicentral distance,but also by fracture faults,seismic wave propagation paths and site effects;moreover,the peak horizontal ground displacement of the AC12 station closest to the epicenter would be about 40 cm,the permanent horizontal displacement about 24 cm,and the vertical uplift about 30.6 cm,meanwile,GPS stations within 140 km of the epicenter could monitor the permanent horizontal deformation with a magnitude greater than 1 cm,while GPS stations within 330 km could monitor the permanent horizontal deformation with a magnitude greater than millimeter level,and except for AC12 and AC45 stations,this earthquake could cause significant permanent settlement at other stations.These results reflected that the focal characteristics of this earthquake would be characterized by thrust,and could provide a reference for subsequent research work;furthermore,the magnitude of this earthquake was estimated to be 7.78 using high-frequency GPS ground peak displacement(PGD),which could be basically consistent with the actual magnitude,indicating the reliability of using high-frequency GPS data for rapid estimation of strong earthquake magnitudes.
关键词
高频全球定位系统(GPS)/位移波形/同震形变/震级估计/矩震级(Mw)/阿拉斯加Mw7.8/地震Key words
high-frequency global positioning system(GPS)/displacement waveforms/coseismic deformation/magnitude estimation/moment magnitude scale(Mw)/Alaska Mw7.8 earthquake引用本文复制引用
基金项目
新疆地震科学基金项目(202213)
国家自然科学基金项目(U2139202)
兰州交通大学青年科学基金项目(2023003)
地震应急青年重点任务(CEAEDEM202218)
出版年
2024
NETL
NSTL
万方数据