| Budget Amount *help |
¥17,420,000 (Direct Cost: ¥13,400,000、Indirect Cost: ¥4,020,000)
Fiscal Year 2018: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2017: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2016: ¥7,280,000 (Direct Cost: ¥5,600,000、Indirect Cost: ¥1,680,000)
Fiscal Year 2015: ¥6,890,000 (Direct Cost: ¥5,300,000、Indirect Cost: ¥1,590,000)
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| Outline of Final Research Achievements |
Our main results of 2-D electrical resistivity structure and of numerical simulation lead us to propose a hypothesis that the low viscosity region in the mantle wedge due to hydration driven by water release from the subducting slab results in highly asymmetric seafloor spreading, which is commonly recognized in many back-arc basins. The resistivity structure was imaged through marine magnetotelluric experiment across a spreading segment in the Southern Mariana Trough back-arc basin. This result shows that a low resistivity region exists beneath the spreading axis and is asymmetrically extended to the subducting slab; the low resistivity region is interpreted as asymmetric melting in the mantle wedge due to hydration driven by water release from the subducting slab. Further, numerical simulation results indicate that the spreading axis is kept locating above the low viscosity mantle zone that capture the mantle upwelling zone due to water release from the subducting slab.
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