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Usui, Yoshiya*; Ueshima, Makoto*; Hase, Hideaki*; Ichihara, Hiroshi*; Aizawa, Koki*; Koyama, Takao*; Sakanaka, Shinya*; Ogawa, Tsutomu*; Yamaya, Yusuke*; Nishitani, Tadashi*; et al.
Journal of Geophysical Research; Solid Earth, 129(5), p.e2023JB028522_1 - e2023JB028522_22, 2024/05
Times Cited Count:1 Percentile:0.00(Geochemistry & Geophysics)We elucidated the crustal heterogeneities beneath a strain concentration area on the back-arc side of the northeastern Japan Arc based on electrical resistivity. By deploying magnetotelluric surveys, we revealed the three-dimensional electrical resistivity structure in the crust, suggesting the coexistence of two types of strain-concentration mechanisms in the strain-concentration area. The shallow conductive layers and lower-crustal conductors appear to act as low-elastic-modulus and low-viscosity areas, respectively, and are responsible for the strain concentration. We found a spatial correlation between the edges of the lower-crustal conductors and the epicenters of large intraplate earthquakes. Weak shear zones in the conductive lower crust may cause stress loading on faults in the brittle upper crust, resulting in large earthquakes. We also identified vertical conductors ranging from the lower crust to Quaternary volcanoes, which may indicate fluid paths to these volcanoes.
Sugimoto, Makoto; Isono, Takaaki; Nunoya, Yoshihiko; Koizumi, Norikiyo; Nakajima, Hideo; Kato, Takashi; Matsukawa, Makoto; Hamada, Kazuya; Matsui, Kunihiro; Nishijima, Gen; et al.
IEEE Transactions on Applied Superconductivity, 10(1), p.564 - 567, 2000/03
Times Cited Count:22 Percentile:70.71(Engineering, Electrical & Electronic)no abstracts in English
Takayanagi, Tadatoshi*; Kuno, Kazuo*; Ichihara, Tadashi*; Nomoto, Kazuhiro*; Hasegawa, Mitsuru*; Koizumi, Norikiyo; Matsui, Kunihiro; Okuno, Kiyoshi
no journal, ,
no abstracts in English
Hasegawa, Mitsuru*; Takayanagi, Tadatoshi*; Ichihara, Tadashi*; Sugimoto, Makoto; Isono, Takaaki; Okuno, Kiyoshi
no journal, ,
no abstracts in English
Usui, Yoshiya*; Ueshima, Makoto*; Hase, Hideaki*; Ichihara, Hiroshi*; Aizawa, Koki*; Koyama, Takao*; Sakanaka, Shinya*; Ogawa, Tsutomu*; Yamaya, Yusuke*; Nishitani, Tadashi*; et al.
no journal, ,
In the back-arc area of the southern Tohoku region, there are several quaternary volcanos and active faults that have the potential to cause M7-class inland earthquakes. In the vicinity of some of the volcanoes, deep low-frequency earthquakes occur, implying the transfer of melt or aqueous fluid. So as to reveal the magma supply system around the area, it is important to reveal the distribution of the subsurface fluid. Also, understanding the fluid distribution helps elucidate the earthquake generation process. To delineate the subsurface electrical resistivity structure, the authors estimated the resistivity structure in the area by performing magnetotelluric surveys and generating the 3-D resistivity structure model with high resolution. In this study, the authors show the resultant electrical resistivity structure and discuss the subsurface fluid distribution as well as its relationship with the volcanic and seismic activities around the study area.