Open Access

Weak interplate coupling beneath the subduction zone off Fukushima, NE Japan, inferred from GPS/acoustic seafloor geodetic observation

  • Yoshihiro Matsumoto12, 32Email author,
  • Tadashi Ishikawa12,
  • Masayuki Fujita12,
  • Mariko Sato12,
  • Hiroaki Saito12,
  • Masashi Mochizuki22,
  • Tetsuichiro Yabuki12 and
  • Akira Asada22
Earth, Planets and Space200860:BF03353114

Received: 30 April 2008

Accepted: 9 June 2008

Published: 18 June 2008


We have been carrying out GPS/acoustic seafloor geodetic observations at several reference points situated along the Japan Trench, a major plate boundary of subduction. A time series of horizontal coordinates of one of the seafloor reference points, located off Fukushima, obtained from seven campaign observations for the period 2002-2008, exhibits a linear trend with a scattering root mean square of about 3 cm. A linear fit to the time series gives an intraplate crustal movement velocity of 3.1 cm per year in a westerly direction, which is significantly smaller than that at the other seafloor reference point 120 km away along the trench axis. This result implies weak interplate coupling in this region.

Key words

GPS/acousticseafloor geodetic observationback-slipOff Fukushimaintraplate deformation