First measurement of the displacement rate of the Pacific Plate near the Japan Trench after the 2011 Tohoku-Oki earthquake using GPS/acoustic technique

Fumiaki Tomita, Motoyuki Kido, Yukihito Osada, Ryota Hino, Yusaku Ohta, Takeshi Iinuma

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)

Abstract

The subduction rate of an oceanic plate may accelerate after large earthquakes rupture the interplate coupling between the oceanic and overriding continental plates. To better understand postseismic deformation processes in an incoming oceanic plate, we directly measured the displacement rate of the Pacific Plate near the Japan Trench after the 2011 Tohoku-Oki earthquake using a GPS/acoustic technique over a period of 2 years (September 2012 to September 2014). The displacement rate was measured to be 18.0 ± 4.5 cm yr-1 (N302.0°E) relative to the North American Plate, which is almost twice as fast as the predicted interseismic plate motion. Because the sum of steady plate motion and viscoelastic response to the Tohoku-Oki earthquake roughly accounts for the observed displacement rate, we conclude that viscoelastic relaxation is the primary mechanism responsible for postseismic deformation of the Pacific Plate and that significant subduction acceleration did not occur at least not during the observation period. Key Points Direct geodetic observations have been made on the Pacific Plate near the trench A high displacement rate was measured after the 2011 Tohoku-Oki earthquake Viscoelastic response following the earthquake probably causes the high displacement rate

Original languageEnglish
Pages (from-to)8391-8397
Number of pages7
JournalGeophysical Research Letters
Volume42
Issue number20
DOIs
Publication statusPublished - 2015 Oct 28

Keywords

  • oceanic plate
  • postseismic deformation
  • seafloor geodesy
  • subduction rate
  • the 2011 Tohoku-Oki earthquake

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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