Premium
Along‐trench variations in the seismic structure of the incoming Pacific plate at the outer rise of the northern Japan Trench
Author(s) -
Fujie Gou,
Kodaira Shuichi,
Sato Takeshi,
Takahashi Tsutomu
Publication year - 2016
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 - 10.1002/2015gl067363
Subject(s) - trench , geology , subduction , seismology , convergent boundary , ridge , oceanic crust , transect , fracture zone , pacific plate , plate tectonics , crust , induced seismicity , tectonics , geophysics , paleontology , oceanography , chemistry , organic chemistry , layer (electronics)
Abstract To investigate along‐trench variations in the seismic structure of the incoming oceanic plate and their effect on water transportation by the oceanic plate, we conducted a wide‐angle seismic survey of a trench‐parallel transect 270 km long on the outer rise of the northern Japan Trench. The resulting seismic structure models show that the central part of the transect is characterized by rough topography, thick oceanic crust, low seismic velocities, and high V p / V s ratios, suggesting pervasive fracturing and high water content (hydration) there. These observations are consistent with the presence of an ancient fracture zone associated with ridge propagation. The trenchward extension of this fracture zone corresponds to an area of low interplate seismicity, low seismic velocities, and high V p / V s ratio around the depth of the subduction interface. Our results suggest that this ancient scar on the oceanic plate influences along‐trench variations in interplate seismic coupling through its effect on water transportation.