【摘要】 东亚岛弧海沟系在平面形态上表现明显的不连续性,各段两端向大陆弯曲,中部向海凸出,这种形式与海底岭脊密切相关;地震活动沿岛弧呈狭窄的带状分布.但其活动性在岛弧的延伸方向上及岛弧间存在明显的差异,表现在岛弧两端或岛弧与海岭的交接地段活动性较强,而中段活动性较弱。菲律宾海板块西侧(靠大陆)活动性较其东侧(靠太平洋)强,马里亚纳弧的NNE和NE方向段地震活动弱于其它的方向段。岛弧地震和大陆地震发生的时间关系,也反映地震活动的应力来源于大陆向海洋的运动。更多还原

【Abstract】 The island -arc is not always in a row. Both ends of each island arc bend toward the continent, and the middle part is convex to the sea. The author considers that there are close relationships between the plane form of island-arcs and submarine ridges. The seismic activity shows a distribution in narrow belt-shape along island arcs, but the activity frequency differs greatly along island-arc stretch or between island-arcs. It is shown that the activity frequency at both ends of island-arcs or the cross point of island-arc and sea ridge is more intensive than that in the middle. And that along island-arcs in the west (near the continent) of the Philippine Plate is more intenssive than that in the east (near the Pacific Ocean), that along the island-arc in NNE and NE direction is less intensive than that in the other direction of Marianasarc. The author considers that these facts may not support the view that the Pacific plate moves and extrudes to the continent on its own initiative, but shows that the stress of seismic activity comes from the movement of continent (or island arc) to the sea.更多还原