Seismic evidence for the 410 km discontinuity beneath the Hindu Kush-Pamir region from the SdP converted phases
Seismic evidence for the 410 km discontinuity beneath the Hindu Kush-Pamir region from the SdP converted phases
复制标题
SdP 转换阶段的兴都库什-帕米尔地区下方 410 公里不连续性的地震证据
DOI：
10.1016/j.tecto.2019.06.001
复制
发表时间：
2019
期刊：
影响因子：
2.9
通讯作者：
Guohui Li
中科院分区：
文献类型：
--
作者：
Qinghui Cui;Yuanze Zhou;Wenlan Li;Rongqiang Wei;Guohui Li
在这项研究中，我们利用SDP转换相的宽带记录探测了兴都库什-帕米尔地区下方的410 Km不连续(410)。在兴都库什之下，410出现在367-384 公里处，平均深度为375 公里；而在帕米尔下面，它出现在380-414 公里处，平均深度为395 公里。与地球模型IASP91相比，410显示出较大的隆起26-43 公里，在兴都库什之下平均35 公里，而较小的隆起7-30 公里，平均在帕米尔以下15 公里。根据地震层析成像图像，S410P转换点都位于兴都库什之下的印度板块内部，并靠近亚洲板块，其中一些位于帕米尔下方的板块内部。亚洲板块附近有7-22 公里的隆起，平均为11 公里；亚洲板块内部有21-30 公里的隆起，平均为25 公里。如果深度变化是由热不均匀引起的，则印度板块内部35 km的隆起指示422 K的低温异常，而亚洲板块附近11 km的隆起和亚洲板块内部25 km的隆起分别指示133 K和302 K的低温异常。我们认为410的抬升可能是由冷俯冲板块引起的，抬升差异暗示了兴都库什和帕米尔下方板块的不同热影响。
In this study, we detect the 410 km discontinuity (410) beneath the Hindu Kush-Pamir region using broadband records of SdP converted phases. Beneath Hindu Kush, the 410 appears at the depths of 367–384 km with an average depth of 375 km; while beneath Pamir, it appears at the depths of 380–414 km with an average depth of 395 km. Compared with the Earth model IASP91, the 410 shows larger uplifts of 26–43 km with an average of 35 km beneath Hindu Kush, and smaller uplifts of 7–30 km with an average of 15 km beneath Pamir. Based on seismic tomographic images, the S410P conversion points are all located inside Indian slab beneath Hindu Kush, and near Asian slab with some of them inside the slab beneath Pamir. The 410 shows the 7–22 km uplifts with an average of 11 km near Asian slab, and the 21–30 km uplifts with an average of 25 km inside Asian slab. If depth variations are caused by the thermal heterogeneity, the 35 km uplift inside Indian slab indicates a low-temperature anomaly of 422 K; whereas the 11 km uplift near Asian slab and 25 km uplift inside Asian slab imply low-temperature anomalies of 133 K and 302 K, respectively. We suggest that the uplifts of the 410 are likely caused by cold subducted slabs, and the uplift differences imply different thermal impacts of the slabs beneath Hindu Kush and Pamir.