Melt region structures beneath back-arc basin spreading centers

研究弧后扩展轴下方的熔体区结构是理解弧后扩展系统的关键。我们研制了一台小型海底磁力仪（OBM），它是为美国海底地震仪（OBS）配套而设计的，是世界上第一台通过国际合作实现的海底地震仪和磁力仪（OBSM）。利用该仪器在东劳扩张轴附近进行了为期一年的海底观测。海洋大地电磁分析使用海底数据，使我们能够成像的电阻率结构的上地幔下的扩展轴，比较，以确定熔融区结构的差异，并了解差异的原因。

Investigations on melt region structures beneath spreading axes are a key to understand back-arc spreading system. We developed a compact ocean bottom magnetometer(OBM), which was designed to be attached to US ocean bottom seismograph(OBS); that became first ocean bottom seismograph and magnetometer(OBSM) in the world achieved by an international cooperation. We carried out one year ocean bottom observation near the Eastern Lau spreading axis using the instruments. Marine magnetotelluric analysis using ocean bottom data allows us to image the resistivity structures of the upper mantle beneath the spreading axis, which were compared to identify differences in melt region structures and to understand the cause of the differences.