Southeast Asia lies within one of the most complex tectonic settings on Earth and exhibits a range of features, including strongly curved subduction zones, arc‐continent collision, and slab break‐off, which are not well understood. To help gain insight into mantle structure and processes beneath this region, we perform an inversion for variations in V_p, V_s, and structure using arrival time information from the ISC‐EHB catalog. The oceanic lithosphere subducting beneath Java is imaged as a positive dV_p and negative d(V_p/V_s) anomaly. At 200 km depth, the forearc mantle beneath Sumatra and Java is revealed by positive dV_p and d(V_p/V_s) anomalies which cease at Sumba island, where negative d(V_p/V_s) anomalies mark the presence of cold Australian lithosphere (down to 200–250 km depth) which is colliding with Sundaland. These negative d(V_p/V_s) anomalies depict a ∼WE trending structure that appears to correspond with the underthrusting of Australian continental crust. One notable salient has a location and shape which appears to coincide with those of ancient terranes or a Gondwana‐related microcontinent reconstructed by paleogeographic studies and may have been entrained in the subduction process. The velocity and d(V_p/V_s) patterns beneath the Banda Arc support the existence of a single curved subducting slab associated with rollback. The extreme extensional strike‐slip setting in Seram produces the highest positive d(V_p/V_s) anomalies in the model which may be due to one or more of widespread serpentinization, high concentrations of intraslab fluid‐filled faulting, and mantle upwelling.

中文翻译：

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东南亚比例的S‐P微分到达时间直接反演

东南亚是地球上最复杂的构造环境之一，并表现出一系列特征，包括强烈弯曲的俯冲带，弧-大陆碰撞和平板断裂，这是人们所不了解的。为了帮助深入了解该区域以下的地幔结构和过程，我们使用ISC-EHB目录中的到达时间信息对V _p，V _s和结构的变化进行了反演。在Java下面俯冲的海洋岩石圈成像为正d V _p和负d（V _p / V _s）异常。在200 km的深度处，苏门答腊和爪哇岛下方的前臂地幔由正的d V _p和d（V _p / V _s）异常揭示，这些异常终止于Sumba岛，而负的d（V _p / V _s）异常表明存在与桑达兰相撞的澳大利亚寒冷的岩石圈（最深200-250公里）。这些负数d（V _p / V _s）异常描绘了一个〜WE趋势结构，似乎与澳大利亚大陆壳的逆冲作用相对应。一个显着的凸出物的位置和形状似乎与古代地形或通过古地理研究重建的冈瓦纳相关的微大陆的位置和形状相符，并且可能已被带入俯冲过程。班达弧下方的速度和d（V _p / V _s）模式支持与回滚相关的单个弯曲俯冲板的存在。Seram中极端的伸展走滑设置会产生最高的正d（V _p / V _s）模型中的异常，可能是由于广泛的蛇形化，高浓度的板内流体充填断层和地幔上涌中的一种或多种引起的。