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Ogawa, Yasuo*; Ichiki, Masahiro*; Kanda, Wataru*; Mishina, Masaaki*; Asamori, Koichi
Earth, Planets and Space (Internet), 66(1), p.158_1 - 158_13, 2014/12
Times Cited Count:77 Percentile:91.85(Geosciences, Multidisciplinary)We have analyzed three-dimensional resistivity structure around Naruko volcano, NE Japan. From the inversion of full tensor components, the following model features are found. Sub-vertical conductors exist at Naruko volcanoes below a depth of few kilometers. The conductor reaches to the surface of Naruko volcano and deepens southward away from the volcano along the backbone ranges. High seismicity in the upper crust is observed above and around the conductors. This implies that the seismicity is fluid-driven and also that the fluid trap is created by the precipitation of quartz due to loss of solubility at shallow depth.
Motoyama, Aoi*; Ogawa, Yasuo*; Uyeshima, Makoto*; Asamori, Koichi; Uchida, Toshihiro*; Hase, Hideaki*; Koyama, Takao*; Sakanaka, Shinya*; Yamaya, Yusuke*; Aizawa, Koki*; et al.
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no abstracts in English
Motoyama, Aoi*; Ichiki, Masahiro*; Ogawa, Yasuo*; Uyeshima, Makoto*; Asamori, Koichi; Uchida, Toshihiro*; Koyama, Takao*; Sakanaka, Shinya*; Hase, Hideaki*; Aizawa, Koki*; et al.
no journal, ,
We compiled the magnetotelluric (MT) and geomagnetic transfer function (GDS) data which were acquired by Uchida (2004), Umeda et al. (2008), Asamori et al. (2011), Uyeshima (private comm.) and Ogawa (private comm). The 118 observation sites locate in the study area. Both MT and GDS frequency response was used to model three-dimensional resistivity distribution of the southern Tohoku district, NE Japan. The resultant resistivity model reveals no conductor beneath the onshore forearc in Fukushima prefecture. The model rather shows resistor there with over several-thousand ohm-m, which corresponds to the Abukuma batholiths. Thus, our model indicates that the area only around Iwaki-city is peculiar forearc, where fluid migrates upward from deep crust.