Two‐dimensional electrical section beneath the eastern margin of Japan Sea
Two‐dimensional electrical section beneath the eastern margin of Japan Sea
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DOI：
10.1029/2006gl027435
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发表时间：
2006-11
影响因子：
5.2
通讯作者：
H. Toh;K. Baba;M. Ichiki;T. Motobayashi;Y. Ogawa;M. Mishina;I. Takahashi
中科院分区：
文献类型：
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作者：
H. Toh;K. Baba;M. Ichiki;T. Motobayashi;Y. Ogawa;M. Mishina;I. Takahashi
四个海底电磁仪提供了九个多月的海底地球电磁数据，以揭示日本海东缘之下的地幔动力学，迄今为止，日本海东缘多次发生了几次大的危险地震。对来自海底阵列的高质量大地电磁（MT）数据以及日本东北部另外四个陆地站点的数据进行了分析，并仔细校正了地形/水深影响，以提取每个站点的二维（2D）MT响应。在这里，我们展示了如何通过反演校正的2D MT响应得到的2D电截面描绘了由冷而快速的俯冲太平洋板块向楔和弧后地幔深处注入流体。在佐渡洋脊下150至200 km深度处发现的高电导率异常可能是直接的现场证据，支持水以蛇纹岩的形式从地球表面输送到楔和弧后地幔。
Four ocean bottom electromagnetometers provided seafloor geoelectromagnetic data for more than nine months in order to reveal mantle dynamics beneath the eastern margin of Japan Sea, where several large and hazardous earthquakes have repeatedly occurred so far. High‐quality magnetotelluric (MT) data from the seafloor array, together with those of four additional land sites in northeast Japan, were analyzed and carefully corrected for topographic/bathymetric effects to extract two‐dimensional (2D) MT responses at each site. Here we show how the 2D electrical section derived by inverting the corrected 2D MT responses depicts fluid injection deep into the wedge and back‐arc mantle by the cold and fast subducting Pacific plate. A high conductivity anomaly found beneath the Sado Ridge at depths ranging from 150 to 200 km may be direct field evidence that supports water transportation from the Earth's surface to the wedge and back‐arc mantle in the form of serpentinite.