2017 Fiscal Year Final Research Report
Comprehensive study on waveform analysis, model, and simulations for understanding the mechanism of anomalously large intensity caused by deep earthquakes
| Project/Area Number |
26400444
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Solid earth and planetary physics
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| Research Institution | The University of Tokyo |
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Principal Investigator |
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| Project Period (FY) |
2014-04-01 – 2018-03-31
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| Keywords | 地震 / 深発地震 / 異常震域 / MOW / 地震波伝播シミュレーション |
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| Outline of Final Research Achievements |
We examined the broadband waveform of deep-focus earthquakes occurring beneath Sea of Japan and find that the S waveforms suddenly change to show low-frequency precursor as the source depth increase over 400 km. Since it is anticipated to be occur due to the effect of wedge-shaped low-wavespeed MOW, we conducted finite-difference method simulation of seismic wave for the deep Vladivostok earthquake (578 km, Mw6.8) of 12 Feb. 2010. The result of simulation demonstrateed that the effect of low-wavespeed anomaly of MOW for guiding seismic wave in frequency between 2 to 4 Hz towards upward along the slab. Due to this, the slab-waveguide effect becomes 3 times larger than that without MOW.
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| Free Research Field |
地震学
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