台湾及其邻海的重力特征与构造、地震的关系

Relation between gravity field feature and tectonics and earthquakes in Taiwan and its adjacent regions

分析认为 ,在台湾及其邻海的重力场中 ,具有短波长特征的空间重力异常受地形与海深所制约 .玉山的 2 0 0× 1 0 -5 m/s2 ,琉球海沟的 - 1 6 0× 1 0 -5 ms-2 是其极端反映 .与接近地表物质有关的布格异常 ,除反映莫氏面起伏外 ,也反映了地下的断裂 (如纵谷等 ) ,在它的拐弯处易发生地震 .具有中长波特征的大地水准面是反演地壳厚度的最好资料 ,由此已计算出该区地壳厚度的分布 ,其中最大值为 38km ,最小值为1

Short wave gravity anomaly is correlated to sea floor topography in gravity field of Taiwan and its adjacent regions. Gravity value 200×10 -5 m/s 2 at Yushan and -160×10 -5 m/s 2 at Ryukyu Trench is respectively maximum and minimum gravity values in this area. Bouguer gravity anomaly reflects not only Moho interface undulation, but also faults distribution. In the inflexion of gradient belt of Bouguer gravity anomaly, earthquake are easily occurring. Middle long wave Geoid is the best data to invert crustal thickness. We calculated crustal thickness by using Geoid data, maximum value is 38km; minimum value is 12km in Taiwan and its adjacent regions.[WT5F1]