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First measurement of the displacement rate of the Pacific Plate near the Japan Trench after the 2011 Tohoku‐Oki earthquake using GPS/acoustic technique
Author(s) -
Tomita Fumiaki,
Kido Motoyuki,
Osada Yukihito,
Hino Ryota,
Ohta Yusaku,
Iinuma Takeshi
Publication year - 2015
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 - 10.1002/2015gl065746
Subject(s) - subduction , geology , trench , pacific plate , seismology , plate tectonics , displacement (psychology) , deformation (meteorology) , geodesy , global positioning system , acceleration , viscoelasticity , oceanic crust , vertical displacement , tectonics , oceanography , geomorphology , psychology , telecommunications , layer (electronics) , psychotherapist , chemistry , physics , organic chemistry , classical mechanics , computer science , thermodynamics
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.