由GPS测量得到的台湾两次7级大地震前后
福建沿海地区地壳运动的变化
史粦华 丁学仁 李延兴 胡新康 张静华 张中伏
1）福建省地震局,福州 350003
2）中国地震局第一监测中心,天津 300180
摘 要 福建沿海地区GPS网从1995年建设至今已积累了6期观测资料,分析该网各GPS站位移变化与运动速度变化的时间序列,发现在1999年9月20日（UTC）台湾集集Ms7.7大地震与2001年12月18日（UTC）花莲东Ms7.6大地震前,各GPS站同步出现了向西与向北位移的大幅度偏移,即向东与向南运动速度明显减小。在集集Ms7.7大地震发生后,各GPS站出现了同步的向东与向南位移的大幅度偏移,即向东与向南运动速度大幅度增加。福建沿海地区在1997～2001年期间出现的地壳运动的变化不仅在时间上与集集、花莲东两次7级大地震的孕育发生相关,而且二者在形成机理上一致,都是由孕育这两次地震的应力场决定的。
关键词 福建沿海 位移变化 速度变化 形变机理 地震
THE CRUSTAL MOVEMENT CHANGE IN COASTAL AREAS OF FUJIAN BEFORE AND AFTER TWO M7 EARTHQUAKES IN TAIWAN FROM GPS SURVEY
Shi Linhua1) Ding Xueren1) Li Yanxing2) Hu Xinkang2) Zhang Jinghua2) Zhang Zhongfu2)
1).Earthquake Administration of Fujian Province, Fuzhou 350003
2) First Crust Monitoring and Application Center, China Earthquake Administration, Tianjin 300180
Abstract The GPS network of Fujian have been 6 time surveying data from 1995 to this day. We analyzed change at time orders of displacement and movement velocity, discovered westward and northward large sync-deviation of GPS sites as that eastward and southward movement velocity decrease obvious before CHI-CHI Ms7.7earthquake in Sept.20,1999 (UTC) and Ms7.6 in East of Hualian in Dec.18,2001 (UTC). Eastward and southward large sync-deviation of GPS sites as that movement velocity large increase occurred after CHI-CHI Ms7.7 earthquake. The crustal movement change in 1997~2001 in coastal areas of Fujian have relative to growth and occurrence of CHI-CHI and East of Hualian earthquakes in time not only, but their growth mechanism are consistency which have decided by stress field of growing these two time earthquakes.
Key words: coastal areas of Fujian, displacement change, velocity change, deformation mechanism, earthquake