A total of 10,586 P‐to‐S radial receiver functions recorded by 64 broadband seismic stations were utilized to image the 410 and 660 km discontinuities (d410 and d660, respectively) bordering the mantle transition zone (MTZ) beneath the Sumatra Island, the Malay Peninsula, and the western margin of the South China Sea. The d410 and d660 were imaged by stacking receiver functions in successive circular bins with a radius of 1°, after moveout corrections based on the 1‐D IASP91 Earth model. The resulting apparent depths of the discontinuities exhibit significant and spatially systematic variations. The apparent depths of the d410 and d660 range from 382 to 459 km and 637 to 700 km with an average of 406 ± 13 and 670 ± 12 km, respectively, while the corresponding values for the MTZ thickness are 217 to 295 km and 261 ± 13 km. Underneath southern Sumatra and adjacent regions, the MTZ is characterized by an uplifted d410 and a depressed d660. While the former is probably caused by the low temperature anomaly, the latter is most likely related to a combination of the low temperature anomaly and dehydration associated with the subducted Australian Plate that has reached at least the d660. In contrast, an abnormally thin MTZ is imaged to the southwest of the Toba Caldera. This observation, when combined with results from previous seismic tomography studies, can be explained by advective thermal upwelling through a slab window.

中文翻译：

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苏门答腊俯冲带附近的板块脱水和地幔上涌：来自地幔过渡带不连续性的接收器功能成像的证据

总共10586的P -到- š由64个宽带地震台站记录径向接收机功能被用来在图像410个660公里不连续性（分别为D410和D660）接壤，苏门答腊岛之下的地幔过渡带（MTZ），马来半岛和南海西部边缘。根据一维IASP91 Earth模型校正位移后，通过将接收器功能堆叠在半径为1°的连续圆形仓中来对d410和d660进行成像。所产生的不连续的表观深度表现出明显的空间上的系统变化。d410和d660的视在深度范围为382至459 km和637至700 km，平均为406  ±  13和670 ± MTZ厚度分别为12 km和217至295 km和261  ±  13 km。在苏门答腊南部和邻近地区下方，MTZ的特征是d410升高而d660降低。尽管前者可能是由低温异常引起的，但后者最有可能与低温异常和与俯冲的澳大利亚板块至少达到d660相关的脱水有关。相反，在鸟羽破火山口的西南部成像了异常稀薄的MTZ。结合以前的地震层析成像研究的结果，可以通过平板窗对流热上升解释这一观察结果。