Characterization of Crustal and Uppermost‐Mantle Seismic Discontinuities in the Ontong Java Plateau
Characterization of Crustal and Uppermost‐Mantle Seismic Discontinuities in the Ontong Java Plateau
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翁通爪哇高原地壳和上地幔地震不连续特征
DOI：
10.1029/2018jb016970
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
Kobayashi T.
中科院分区：
文献类型：
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作者：
Tonegawa T.;Miura S.;Ishikawa A.;Sano T.;Suetsugu D.;Isse T.;Shiobara H.;Sugioka H.;Ito A.;Ishihara Y.;Tanaka S.;Obayashi M.;Yoshimitsu J.;Kobayashi T.
西南太平洋的早白垩世翁通爪哇高原（OJP）是地球上体积最大的海洋高原，人们进行了广泛的观测以揭示其形成和演化。然而，由于迄今为止对 OJP 及周边地区的海底地震观测还不够，此类实验能够产生有关 OJP 地壳和地幔结构的额外信息。为了对从地壳到最上地幔的地震速度不连续性进行成像，我们对 OJP 及其周围区域部署的 17 个宽带海底地震仪和位于密克罗尼西亚海洋岛屿上的 3 个宽带站（一个：永久，两个：临时）获取的地震记录进行了接收函数分析。结果显示，OJP 中部的中地壳不连续性和莫霍面深度分别为 10-20 公里和 30-40 公里（距基底顶部）。此外，在 OJP 中央 55-60 公里（距基底顶部）深度处也拍摄到了地幔不连续性。这些边界并未在 OJP 之外成像，这意味着它们是 OJP 的特征。此外，接收函数图像显示OJP东部20公里深度处有莫霍面信号，此前很少在此进行地震勘探。该深度与可能与 OJP 分离的马尼希基高原和希库朗吉高原的深度相当。
The Early Cretaceous Ontong Java Plateau (OJP) in the southwestern Pacific Ocean is the largest oceanic plateau by volume on Earth, and a broad range of observations has been conducted to reveal its formation and evolution. However, because seafloor seismic observations of the OJP and surrounding areas have been insufficient so far, such experiments are capable of generating additional information regarding the crustal and mantle structure of the OJP. To image seismic velocity discontinuities from the crust to the uppermost mantle, we applied receiver function analysis to seismic records acquired by 17 broadband ocean bottom seismometers deployed across the region in and around the OJP and 3 broadband stations located on ocean islands in Micronesia (one: permanent, two: temporary). The results revealed midcrustal discontinuities and the Moho at depths of 10–20 and 30–40 km (from the top of the basement), respectively, in the central OJP. Moreover, a mantle discontinuity was also imaged at the depth of 55–60 km (from the top of the basement) in the central OJP. These boundaries were not imaged outside the OJP, implying that they are characteristic features of the OJP. In addition, receiver function images showed Moho signals at the depth of 20 km in the eastern OJP, where few previous seismic exploration surveys have been conducted. This depth is comparable with that found in the Manihiki and Hikurangi Plateaus that were potentially separated from the OJP.