Magnetotelluric imaging for fluids in the crust and upper mantle beneath the southern part of Northeast Japan subduction zone
| Autor: | Diba, D., Uyeshima, M., Ichiki, M., Sakanaka, S., Tamura, M., Yuan, Y., Gresse, M., Yamaya, Y., Usui, Y. |
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| Rok vydání: | 2023 |
| Zdroj: | XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) |
| DOI: | 10.57757/iugg23-0773 |
| Popis: | Northeast Japan is one of the world's most active subduction zones, having great earthquakes and volcanic eruptions, such as the M9.1 Tohoku Earthquake in 2011. Efforts to understand the subsurface structure via magnetotelluric studies have been extensive because electrical resistivity is sensitive to fluids in the crust and upper mantle. As a result, the deep, regional resistivity structure has been obtained beneath the northern and central parts of Northeast Japan (Ogawa et al., 1986; Ichiki et al., 2015). In this study, we aimed to image the southern part. This area has quaternary volcanoes on the backbone range and the back-arc side, active deformation regions, and shallow to deep seismic activities. Such activities are generally viewed to be caused by fluids in the crust and upper mantle that originated from the subducting slab (e.g., Iwamori, 1998; Wallace, 2005). So, we performed a wide-band magnetotelluric study by deploying electromagnetic field recording stations on three parallel NW-SE profile lines across the island arc. Each line consists of about 15 stations with nearly 10 km intervals. We estimated the MT impedance, vertical magnetic field transfer function (VMTF), and inter-station horizontal magnetic field transfer function (HMTF) at periods 0.03 - 13,000 seconds using the BIRRP code (Chave and Thomson, 2004). FEMTIC inversion code (Usui, 2015; Usui et al., 2017) was used for three-dimensional inversion because it can jointly invert the three response functions. In the presentation, we discuss the resulting resistivity structure and its correlation with active volcanoes and seismic activities. The 28th IUGG General Assembly (IUGG2023) (Berlin 2023) |
| Databáze: | OpenAIRE |
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