GPS station short-term dynamic characteristics of micro displacement before Menyuan M6.4 earthquake

作     者：Wei Feng Jinwei Ren Zaisen Jiang 

作者机构：Institute of Earthquake ScienceChina Earthquake AdministrationBeijing 100036China China Earthquake Networks CenterBeijing 100045China 

出 版 物：《Geodesy and Geodynamics》 (大地测量与地球动力学（英文版）)

年 卷 期：2016年第7卷第4期

页      面：237-244页

学科分类：081802[工学-地球探测与信息技术] 070801[理学-固体地球物理学] 07[理学] 08[工学] 081105[工学-导航、制导与控制] 0708[理学-地球物理学] 0818[工学-地质资源与地质工程] 0804[工学-仪器科学与技术] 0811[工学-控制科学与工程] 

基　　金：funded by the Project of National Natural Science Foundation of China,based on GPS and leveling data simulation and study on the state of seismogenic deformation field and its mechanical characteristics(41274008) the Basic Research Project of Institute the Earthquake Science,China Earthquake Administration,crustal deformation observation experiment and dynamic process simulation research(2014IES010201) 

主　　题：Menyuan earthquake Global positioning system (GPS) Undulatory motion Hilbert-Huang transform (HHT) Cross spectrum 

摘      要：Continuous observation data from 24 GPS stations are selected in the area （33.0°N-41.0°N, 95.0°E-105.0°E） for this study （the period is from Jan. 1, 2015 to Jan. 20, 2016）. Three components, NS, EW and UD, of the daily solutions are filtered by the Hilbert-Huang transform （HHT） with frequency band of 5.787×10^-7-7.716 ×10^-8 Hz （20-150 days in period）. And short-term dynamic characteristics of micro displacement before Menyuan M6.4 earthquake are studied by using the temporal dependencies and cross spectrum analysis. The results show that before the earthquake the horizontal undulatory motions are higher than the average level in the series data which indicate the disturbance feature of regional stress before the earthquake. Three GPS stations on Qinghai-Tibet Plateau with their setting perpendicular to the seismogenic fault have consistent movement. The increase of amplitude of the horizontal micro motion observed before the quake is conducive to the earthquake occurrence. However, we could not be sure if the undulatory motion triggered the earthquake. It is quite necessary to build more GPS continuous observation stations and optimize the monitoring network so as to improve the understanding of the shortterm dynamic crustal variation before earthquake.