摘要
采用国际通用高精度数据处理软件对1999—2015年汶川地震震后龙门山断裂两侧分布的109个GNSS连续站和区域站资料进行数据处理与分析,得到各测站点水平向坐标时间序列。考虑2013年芦山地震同震位移影响,通过时间序列分析,获取震后该区域109个测站在2010—2015年间累计震后形变场,断裂带上盘靠近震中的近场区域,水平向最大震后位移达到5~7cm。基于震后黏弹性松弛模型,通过格网搜索,根据3种不同破裂模型分别反演龙门山断裂上盘中上地壳最佳弹性层厚度估值与下地壳/上地幔黏弹性层最佳黏滞系数,获取3种不同破裂模型在2010—2015年间震后形变观测值与模拟值分布。根据模型二反演得到的模型参数,推估汶川地震在未来几十年内对周边区域地壳形变影响,其中仅2018—2058年40年尺度累计震后位移最大能达到19cm。
Processing and analysis of 109 GNSS continuous stations and campaign stations after Wenchuan earthquake on both sides of the Longmen shan fault during the year of 1999—2015,we use the international highprecision data processing software to obtain the time series of horizonal coordinate for each site.Considering the effect of coseismic deformation of Lushan earthquake in 2013 and performing time series analysis,get the postseismic deformation field of 109 stations in the earthquake area during 2010—2015,maximum postseismic displacement in horizontal up to 5~7 cm in the epicenter near the upper falut.Based on the model of postseismic viscoelastic relaxation and searched by grid,inverted the best thickness of the middle to upper crustal elastic layer and the best coefficient of viscosity in viscoelastic layer of lower crust and upper mantle according to three different rupture models,and obtained the distribution of deformation from observation and simulation value of three different rupture models during 2010—2015.According to the parameters obtained by inversion of model 2,calculate the impact on crustal deformation in the surrounding area in next few decades after Wenchuan earthquake,the maximum cumulative postseismic deformation in 40 years during 2018—2058 up to 19 cm.
引文
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