Open Access

The electrical structure across the Median Tectonic Line in east Shikoku, southwest Japan

  • Tadanori Goto1, 4Email author,
  • Satoru Yamaguchi2,
  • Norihiko Sumitomo1 and
  • Katsumi Yaskawa3
Earth, Planets and Space201450:BF03352127

https://doi.org/10.1186/BF03352127

Received: 20 January 1997

Accepted: 9 April 1998

Published: 6 June 2014

Abstract

The Median Tectonic Line (MTL) is one of the longest tectonic lines in Japan with the lateral movement. In order to investigate the subsurface structure around the MTL, we carried out the magnetotelluric soundings and the geomagnetic depth soundings in the northeastern Shikoku district, southwest Japan. We estimated the resistivity model at the depth from the surface to 10 km, which explains the observed apparent resistivities and phases. The most remarkable feature of the resistivity model is that the subsurface extension of the MTL has a north dip down to 5 km depth. This dipping interface also corresponds to a reflection seismic result. The north dipping MTL cannot be created by just a present strike slip motion. It requires that the horizontally compressive stress dominated in the early stage of the fault.