卡斯卡迪亚慢滑移信息的GNSS时空探测  

Spatiotemporal detection of slow slip information in Cascadia based on GNSS

作　　者：杜久升[1] 王羽 侯争[1] 冯云超 DU Jiusheng;WANG Yu;HOU Zheng;FENG Yunchao(School of Surveying and Land Information Engineering,Henan Polytechnic University,Jiaozuo,Henan 454003,China)

机构地区：[1]河南理工大学测绘与国土信息工程学院,河南焦作454003

出　　处：《导航定位学报》2024年第1期130-136,共7页Journal of Navigation and Positioning

基　　金：河南省科技攻关项目(232102321004,212102310436);河南省高等学校重点科研项目(22A420005)。

摘　　要：针对断层慢滑移时空分布信息探测困难的问题,基于全球卫星导航系统(GNSS)坐标序列,提出一种利用多通道奇异谱分析(MSSA)探测卡斯卡迪亚消减带慢滑移事件时空分布的方法:根据慢滑移分量的振荡特点确定窗口长度,采用时间迟滞矩阵对协方差阵进行增广,以提高对异常信息的识别能力;对振幅归一化获取空间响应,通过快速傅里叶变换分析慢滑移频谱特征。结果表明,卡斯卡迪亚消减带2007-01-05—2007-02-23和2008-04-22—2008-06-14发生了2次慢滑移事件,2次事件呈东南、西北区域的反向运动特征,且东南部响应程度明显高于西北地区;频谱特征显示,慢滑移信息表现为低频特征,且主要为随机游走噪声。研究结果可为板内地震前兆性信息探测提供参考。Aiming at the problem of difficulty in detecting the spatiotemporal distribution information of fault slow slip,the paper proposed a method to extract the spatiotemporal distribution of slow slip events in the Cascadian subduction zone by using the multichannel singular spectrum analysis(MSSA)based on the global navigation satellite system(GNSS)coordinate series:the window length was set according to the oscillation characteristics of the slow slip signal,and the time hysteresis matrix was used to augment the covariance matrix for improving the identification ability of abnormal information;then the spatial response was obtained by amplitude normalization,and the slow slip spectrum characteristics were analyzed by fast Fourier transform.Results showed that two slow-slip events had occurred in the Cascadia subduction zone from January 5,2007 to February 23,2007 and from April 22,2008 to June 14,2008;the two events presented the reverse movement characteristics of the southeast and northwest regions,and the response degree of the southeast region was significantly higher than that of the northwest region;moreover,the spectrum characteristics illustrated that the slow slip information would be characterized by low frequency and mainly random walk noise.In general,the results could provide a reference for the detection of precursory information of earthquakes in the plate.

关 键 词：全球卫星导航系统(GNSS) 慢滑移 多通道奇异谱分析(MSSA) 快速傅里叶变换 随机游走噪声 

分 类 号：P227[天文地球—大地测量学与测量工程] P228.4[天文地球—测绘科学与技术]