A Three-dimensional electrical conductivity model of the crust beneath the southern Tohoku district, NE Japan

Motoyama, Aoi*; Ichiki, Masahiro*; Ogawa, Yasuo*; Uyeshima, Makoto*; Asamori, Koichi; Uchida, Toshihiro*; Koyama, Takao*; Sakanaka, Shinya*; Hase, Hideaki*; Aizawa, Koki*; Yamaya, Yusuke*

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.