【摘要】 运用经验模态分解方法,提取定点倾斜和应变固体潮观测数据的长趋势变化。通过对在震中周边600km范围内的地震台站的倾斜潮汐长趋势变化进行倾斜矢量分析,发现在2010年4月14日青海玉树MS7.1地震前,距震中31km的玉树台倾斜矢量曲线出现"打结"现象。同时,对该区域内的应变潮汐长趋势变化进行面应变分析,发现处于玉树—甘孜断裂带两端的格尔木台和甘孜台的面应变在玉树地震发生前半年出现了异常转折,这种变化可能反应了该断裂带在地震前的面应变的变化。经验模态分解方法可用于认识某个区域内的倾斜、应变状态。更多还原

【Abstract】 On Apr.14,2010,an MS7.1 earthquake occurred in Yushu,Qinghai.Using the Empirical Model Decomposition method,we analyzed the data of tilt earth tide and the data of strain earth tide from 6 stations(Yushu,Xiangcheng,Delingha,Huangyuan,Geermu,Ganzi)located within 600km from the Yushu earthquake’s epicenter,to extract the long-trend variations of tilt earth tide and strain earth tide.Some abnormalities were found before the Yushu earthquake on the tilt vector map and plane strain map.The curves of tilt vector at Yushu Station which was only 31 km away from the epicenter quickly twisted before the Yushu earthquake.The curves of plane strain at Geermu Station and Ganzi Station which were located at both ends of the Yushu-Ganzi Fault changed their directions six months before the earthquake.This may reflect the Fault Zone’s plane strain change before Yushu earthquake.更多还原