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A fault‐zone conductor beneath a compressional inversion zone, northeastern Honshu, Japan
Author(s) -
Ichihara Hiroshi,
Uyeshima Makoto,
Sakanaka Shinya,
Ogawa Tsutomu,
Mishina Masaaki,
Ogawa Yasuo,
Nishitani Tadashi,
Yamaya Yusuke,
Watanabe Atsushi,
Morita Yuichi,
Yoshimura Ryokei,
Usui Yoshiya
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl047382
Subject(s) - geology , magnetotellurics , seismology , fault (geology) , tectonics , inversion (geology) , petrology , strike slip tectonics , conductor , electrical resistivity and conductivity , geometry , mathematics , engineering , electrical engineering
A resistivity section based on magnetotelluric data was obtained for the Shonai Plain fault in northeastern Honshu, Japan. Faults in this area were created as normal faults during the opening of the Japan Sea in the Miocene but are now reactivated as high‐angle reverse faults under compressional tectonics. Geological interpretations of the resistivity section support the proposed fault reactivation. An estimated east‐dipping conductor along a deep part of the Shonai Plain fault system probably represents a fluid‐rich zone around the fault zone. The high 3 He/ 4 He ratio near the fault indicates transportation of mantle fluid through this fluid‐rich zone. These evidences may reflect the development of pronounced fracture permeability after fault rupturing, as in the fault‐valve hypothesis.