Effective elastic thickness (T_e) is a proxy for lithospheric strength. Here, we present high-resolution T_e maps over the Northeast Indian Seamount Province and surroundings using both multitaper and wavelet analyses of coherence between Bouguer gravity anomaly and topography. Both methods show fairly equivalent spatial variations of T_e that are representative of the tectonic provinces. The islands, seamount provinces, Wharton Basin, and Sunda trench are characterized by low T_e, indicating weak lithosphere due to lithospheric extension, and/or multiple episodes of magmatism. Moderate and high T_e recovered in the Java trench, Sumatra, Billiton Island and northwest of Nicobar Fan suggest a relatively cold and strong upper mantle. Locally, T_e can be correlated with geothermal proxies, such as surface heat flow and Curie-point depth, but temperature only plays a late-stage role in controlling the lithospheric strength within an isothermal range of 150–600 °C. Tectonic factors such as multiple episodes of magmatism, lithospheric extension, uplift, and relaxed tectonic stress of the lithosphere have dynamically affected the flexural rigidity of the lithosphere in the region. The Sumatra forearc shows crustal thickening due to diffused deformation at all crustal levels that promotes fracturing and upward migration of fluids, whereas the Java forearc shows relatively strong lithosphere and shallow fore-arc mantle.

有效弹性厚度 ( T _e ) 代表岩石圈强度。在这里，我们使用布格重力异常和地形之间的相干性的多锥分析和小波分析，展示了印度东北海山省和周边地区的高分辨率T _e地图。两种方法都显示出相当等效的代表构造省的T _e空间变化。岛屿、海山省、沃顿盆地和巽他海沟的特点是T _e低，表明由于岩石圈伸展和/或多次岩浆活动导致岩石圈弱。中高T _e在爪哇海沟、苏门答腊、比利顿岛和尼科巴扇西北部发现的表明上地幔相对寒冷而坚固。在当地，Ť _ē可以与地热代理相关，例如地表热流和居里点深度，但温度仅在控制岩石圈强度在 150-600 °C 的等温范围内发挥后期作用。多次岩浆活动、岩石圈伸展、隆升、岩石圈构造应力松弛等构造因素动态影响了该地区岩石圈的抗弯刚度。苏门答腊前弧显示出由于在所有地壳层级的扩散变形导致地壳增厚，促进了流体的破裂和向上迁移，而爪哇前弧显示出相对强的岩石圈和浅前弧地幔。