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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 the continuous observation data of GPS reference stations around the epicenter of the M6.4 Moyuan earthquake in 2016, the three-component displacement time series analysis and de-periodic analysis, the baseline time series analysis of stations and the strain time series analysis of the deformation units near the epicenter were discussed. Before the earthquake crustal deformation characteristics. The results show that: the quasi-synchronous variation of the displacement component time series appears abnormal, the anomalous component is mainly EW component, the anomaly appears about one month before the earthquake, the amplitude is about 6 ~ 10mm; QHME and QHQL two GPS reference stations after the cycle Of the NS and EW components in the second half of 2015. The baseline rate of shortening near the epicenter is obviously smaller, indicating that there is a certain degree of strain accumulation before the epicenter. Before the epicenter, EW line strain and surface strain rate in the vicinity of the epicenter have been weakened since 2014, indicating that there is evidence of deformation loss in the past two years. It also shows that a certain degree of strain energy is accumulated in the area before the earthquake.