The Okinawa Trough is an active back-arc basin of the Ryukyu island arc-trench system caused by the Phillippine Sea plate subduction. Its unique location makes it attractive to study the lithosphere of continental margins, and it is of great significance to understand the dynamic mechanism of the trench-arc-basin convergent plate boundary. In this paper, we developed the spectral correlation method to calculate the effective elastic thickness of the lithosphere in the study area. The results show that the effective elastic thickness of the lithosphere is distributed in the range of 9–30 km and the lithosphere strength gradually decreases accordingly. Comparing the spatial variations of effective elastic thickness with the data sets of tectonic activities, we conclude that: The spatial variations of the effective elastic thickness have the negative correlation with that of the heat flow. The thermal tectonic activities of the trough gradually become intense from north to south. There are close links between the spatial variations of the effective elastic thickness and the distribution earthquakes. Most of earthquakes are distributed in the relatively lower effective elastic thickness areas or steep effective elastic thickness gradient zones, which indicate that the weak lithosphere and areas with steep change of effective elastic thickness are prone to accumulate and then release tectonic stresses causing earthquakes. The total characteristics of tectonic activities of the Okinawa Trough indicate a strong trend from north to south in the deep region, and the opposite in the shallow region.

冲绳海槽是由菲律宾海板块俯冲引起的琉球岛弧沟系统的活跃弧后盆地。它的独特位置使它对研究大陆边缘的岩石圈具有吸引力，并且对了解沟槽-弧盆盆地收敛板边界的动力学机制具有重要意义。在本文中，我们开发了光谱相关方法来计算研究区域岩石圈的有效弹性厚度。结果表明，岩石圈的有效弹性厚度分布在9-30 km范围内，岩石圈强度相应地逐渐减小。比较有效弹性厚度的空间变化与构造活动的数据集，我们得出以下结论：有效弹性厚度的空间变化与热流负相关。海槽的热构造活动从北向南逐渐增强。有效弹性厚度的空间变化与分布地震之间有着密切的联系。大部分地震分布在有效弹性厚度相对较低的区域或有效弹性厚度梯度较陡的区域，表明弱岩石圈和有效弹性厚度变化较大的区域容易积聚，然后释放构造应力，引起地震。冲绳海槽的构造活动的总体特征表明，深部区域从北向南呈强趋势，而浅部区域则呈相反趋势。