摘要
基于2016年门源M6.4地震震中周边GPS基准站的连续观测资料,通过三分量位移时间序列分析和去周期化分析、站间基线时间序列分析以及震中附近变形单元的应变时间序列分析,探讨了震前地壳变形特征。结果表明：位移分量时间序列出现群体性的准同步变化异常,异常分量主要为EW分量,异常出现在震前一个月左右,幅度约为6-10mm;QHME和QHQL两个GPS基准站去周期后的NS、EW分量在2015年下半年出现自有观测数据以来最大幅度的趋势转折变化;震中附近的基线缩短速率明显较小,表明震中附近区域在震前存在一定程度的应变积累背景;震前、震中附近区域的EW向线应变和面应变率从2014年开始存在弱化现象,表明该区域近两年存在形变亏损的迹象,也反映了该区域在震前积累了一定程度的应变能。
Based on GPS reference data since 2010 surrounding the epicenter of 2016 Menyuan M6.4 earth- quake, the characteristics of crustal deformation before the earthquake are discussed on the basis of the a- nalysis results of the displacement time-series,the processing to remove the periodization, baseline time-se- ries and strain time-series.The results show that the displacement time-series, especially the EW compo- nent of each GPS station appear a synchronous abnormal change since a month before the earthquake, the abnormal range is about 6- 10 mm within 5 days. In addition, the results of remove the periodization of QHME and QHQL station show a biggest tendency change about the EW and NS component in the latter half of the year 2015.The baseline shortening rate smaller significantly near the epicenter,which shows the regions near the epicenters may in an obvious background of strain accumulation.Moreover,the EW strain and plane strain rate began to weaken since 2014.It indicates that the existence of deformation loss region in the past two years,a certain strain accumulation background may exist before the earthquake as well.
出处
《遥感技术与应用》
CSCD
北大核心
2016年第6期1167-1173,共7页
Remote Sensing Technology and Application
基金
地震科技星火计划项目(XH14049
XH16038Y)
甘肃省地震局地震科技发展基金项目(2016M02)
国家自然科学基金项目(51408567
41304048)
