基于GRACE RL05数据研究智利地震长期震后重力变化特征  

Research of the long-term gravity change pattern related to Chile earthquake via GRACE RL05 data

作　　者：严畅达 徐亚[1,2] YAN ChangDa;XU Ya(Key Laboratory of Petroleum Resources Research,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Institutions of Earth Science,Chinese Academy of Sciences,Beijing 100029,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院地质与地球物理研究所,中国科学院油气资源研究重点实验室,北京100029 [2]中国科学院地球科学研究院,北京100029 [3]中国科学院大学,北京100049

出　　处：《地球物理学报》2019年第6期2115-2127,共13页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(91428204和41374139);中国科学院青年创新促进会(2016064)联合资助

摘　　要：利用GRACE卫星重力可对地震引起的大范围重力变化进行观测,并从重力数据中发现主要的变化特征.发生于2010年的MW8.8智利地震震级较高,可观测到震中附近广泛的同震和震后长期重力变化.本文基于GRACERL05Level-2时变重力场数据,对2010年智利地震的同震和震后长期变化进行了计算.对同震变化的计算发现,智利地震引起的同震变化极值达-5μGal,而本文为减小水文信号的干扰而采用的3年平均的方法可以获得良好的效果.在对震后重力变化的计算中发现,智利地震震后在2011-2016年间的重力变化存在先增大后逐渐衰减的过程.对震后变化的拟合表明,智利地震震中附近有约1μGal的震后重力变化,震后变化的特征时间约1.1年.同时,在智利地震中未出现较明显的两个震后变化阶段(短期、长期).Large scale gravity change related to earthquakes could be observed by GRACE satellite gravity data and the changing patterns could be recognized.Co-seismic and post-seismic gravity change could be observed close to the epicenter of the M W8.8 Chile earthquake in 2010.This paper calculated the co-seismic and post-seismic gravity change of the 2010 Chile earthquake based on the GRACE RL05 Level-2 time-variable gravity data.From the co-seismic result,we discovered that the co-seismic maximum gravity change reached -5 μGal.Our method of reducing the disturbance of water mass change by calculating the 3-year average before and after the earthquake performed well.From the post-seismic result,we observed that the gravity change from 2011 to 2016 having a first increase then decrease pattern.The fitting to the post-seismic change revealed that the post-seismic gravity change is about 1μGal close to the epicenter,and the characteristic time is about 1.1 year.The Chile earthquake didn′t show a typical post-seismic change of two terms (short and long).

关 键 词：智利地震 GRACE 震后重力变化 

分 类 号：P228[天文地球—大地测量学与测量工程]