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Postseismic slip associated with the 2007 Chuetsu-oki, Niigata, Japan, Earthquake (M 6.8 on 16 July 2007) as inferred from GPS data

  • Takeshi Iinuma16Email author,
  • Yusaku Ohta16,
  • Satoshi Miura16,
  • Kenji Tachibana16,
  • Takeshi Matsushima26,
  • Hiroaki Takahashi36,
  • Takeshi Sagiya46,
  • Takeo Ito46,
  • Shin’ichi Miyazaki56,
  • Ryosuke Doke66,
  • Akira Takeuchi66,
  • Kayo Miyao16,
  • Akihiko Hirao26,
  • Takahiro Maeda36,
  • Teruhiro Yamaguchi36,
  • Masamitsu Takada36,
  • Makiko Iwakuni56,
  • Tadafumi Ochi56,
  • Irwan Meilano46 and
  • Akira Hasegawa16
Earth, Planets and Space200860:BF03353141

Received: 30 November 2007

Accepted: 26 February 2008

Published: 18 November 2008


Postseismic crustal deformation associated with the 2007 Chuetsu-oki Earthquake, which occurred on 16 July 2007 with a magnitude of 6.8 at the southeastern rim of the Sea of Japan, near the coast of Mid-Niigata Prefecture, Central Japan, are detected by GPS observations. We analyzed continuous GPS data from the sites of the Geographical Survey Institute of Japan (GSI) and another dense temporary network, which we established just after the main shock to reveal spatio-temporal evolution of postseismic slip for 50 days after the main shock by geodetic inversion methods. Four models of faults are configured following Ohta et al. (2008, this issue), and these are optimized based on ABIC (Akaike’s Bayesian Information Criterion). The results of the inversion analysis show that the postseismic slip on the faults occurred at a downdip and updip extension of the coseismically slipped portion. The slip in the shallower portion decayed to be negligible within 2 weeks, and the slip in the deeper portion was still large after the slip in the shallower portion had almost terminated.

Key words

Crustal deformationpostseismic slipGPSstrain concentrated zoneNiigata-Kobe Tectonic Zone