岛弧-海沟地区浅源强震分布和地球自转

本文初步研究了全球某些岛弧海沟构造系统中浅源强震的震中位置和地球自转速率变化的相关关系（简称ER关系）。汤加-克马德克、印尼爪哇、日本和阿拉斯加-阿留申等的岛弧海沟地段的ER关系表明,在海沟及其附近的重力负异常地区内,地震多在地球自转加快的年份中发生;而在岛弧及其附近的重力正异常地区内,地震主要发生在自转相对减慢的年份中。这种特征可能不仅和海洋与大陆板块汇聚边界的岛弧海沟上的基本应力状态有关,而且与自转速率不均匀产生的附加应力状态有关。

DISTRIBUTION OF THE SHALLOW EARTHQUAKES INTHE ISLAND ARC-TRENCH ZONES ANDTHE EARTH'S ROTATION

The correlation between the epicentral distribution of the stronge shallow earthquakes in some island arc-trench systems and the rotation velocity variation of the earth was preliminarily analysed （ER correlation）.The ER correlations of the Tonga-Kermadec. Java, Japan and Alaska-Aleutian island arc-trench show that the shocks under the zones of deep-sea trench and seaward with the negative gravity anomaly occurred mainly in the years with accelerated rotation of the earth; the shocks under the zones of island arc and landward of deep-sea trench with the positive gravity anomaly took place in the years with decreased rotation.These correlations depend not only on the state of the basic stress field in the island arc-trench but also on the additional stress field caused by the variation of rotation velocity of the earth.