Widely distributed thrust and strike-slip faults within subducting oceanic crust in the Nankai Trough off the Kii Peninsula, Japan

Takeshi Tsuji, Shuichi Kodaira, Juichiro Ashi, Jin Oh Park

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

We identified widely distributed thrust and strike-slip faults within subducting oceanic crust in the Nankai Trough, southeast of the Kii Peninsula, Japan, on the basis of 2D and 3D seismic reflection data. The seafloor seaward of the trough axis is deformed by displacement on these intraoceanic reverse faults, producing topographic highs (part of Kashinosaki Knoll). Because the thrust faults extend to the Moho and offset the Moho reflection, they may be related to serpentinization of the mantle due to seawater invasion. These faults are seismically active, given that their geometries are consistent with the focal mechanisms of intraplate earthquakes and microearthquakes. The thrust faults appear to extend landward to a high-density dome within the accretionary prism off the Kii Peninsula. Because the dome and the associated thick accretionary prism are expected to generate high friction at the plate interface due to their large vertical load, the intraoceanic thrusts are likely to have grown with ongoing subduction. Furthermore, because the geometry of the fault system we identified off the Kii Peninsula has characteristics similar to faults at Zenisu Ridge east of our study area, the thrusts observed in the study area may be considered to be the westward continuation of those at Zenisu Ridge. Since the Euler rotation pole of relative motion between the Philippine Sea plate and Zenisu Ridge is consistent with the high-density dome off the Kii Peninsula, we interpret the high-density dome as well as Kashinosaki Knoll as a westward termination of the Zenisu compression zone.

Original languageEnglish
Pages (from-to)52-62
Number of pages11
JournalTectonophysics
Volume600
DOIs
Publication statusPublished - Jul 17 2013

Fingerprint

peninsulas
domes
troughs
strike-slip fault
thrust
oceanic crust
dome
crusts
Japan
trough
slip
ridges
accretionary prism
thrust fault
Moho
prisms
geometry
Philippines
Philippine Sea plate
serpentinization

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Earth-Surface Processes

Cite this

Widely distributed thrust and strike-slip faults within subducting oceanic crust in the Nankai Trough off the Kii Peninsula, Japan. / Tsuji, Takeshi; Kodaira, Shuichi; Ashi, Juichiro; Park, Jin Oh.

In: Tectonophysics, Vol. 600, 17.07.2013, p. 52-62.

Research output: Contribution to journalArticle

@article{dae3e83e960d49af817db9dc096b9f74,
title = "Widely distributed thrust and strike-slip faults within subducting oceanic crust in the Nankai Trough off the Kii Peninsula, Japan",
abstract = "We identified widely distributed thrust and strike-slip faults within subducting oceanic crust in the Nankai Trough, southeast of the Kii Peninsula, Japan, on the basis of 2D and 3D seismic reflection data. The seafloor seaward of the trough axis is deformed by displacement on these intraoceanic reverse faults, producing topographic highs (part of Kashinosaki Knoll). Because the thrust faults extend to the Moho and offset the Moho reflection, they may be related to serpentinization of the mantle due to seawater invasion. These faults are seismically active, given that their geometries are consistent with the focal mechanisms of intraplate earthquakes and microearthquakes. The thrust faults appear to extend landward to a high-density dome within the accretionary prism off the Kii Peninsula. Because the dome and the associated thick accretionary prism are expected to generate high friction at the plate interface due to their large vertical load, the intraoceanic thrusts are likely to have grown with ongoing subduction. Furthermore, because the geometry of the fault system we identified off the Kii Peninsula has characteristics similar to faults at Zenisu Ridge east of our study area, the thrusts observed in the study area may be considered to be the westward continuation of those at Zenisu Ridge. Since the Euler rotation pole of relative motion between the Philippine Sea plate and Zenisu Ridge is consistent with the high-density dome off the Kii Peninsula, we interpret the high-density dome as well as Kashinosaki Knoll as a westward termination of the Zenisu compression zone.",
author = "Takeshi Tsuji and Shuichi Kodaira and Juichiro Ashi and Park, {Jin Oh}",
year = "2013",
month = "7",
day = "17",
doi = "10.1016/j.tecto.2013.03.014",
language = "English",
volume = "600",
pages = "52--62",
journal = "Tectonophysics",
issn = "0040-1951",
publisher = "Elsevier",

}

TY - JOUR

T1 - Widely distributed thrust and strike-slip faults within subducting oceanic crust in the Nankai Trough off the Kii Peninsula, Japan

AU - Tsuji, Takeshi

AU - Kodaira, Shuichi

AU - Ashi, Juichiro

AU - Park, Jin Oh

PY - 2013/7/17

Y1 - 2013/7/17

N2 - We identified widely distributed thrust and strike-slip faults within subducting oceanic crust in the Nankai Trough, southeast of the Kii Peninsula, Japan, on the basis of 2D and 3D seismic reflection data. The seafloor seaward of the trough axis is deformed by displacement on these intraoceanic reverse faults, producing topographic highs (part of Kashinosaki Knoll). Because the thrust faults extend to the Moho and offset the Moho reflection, they may be related to serpentinization of the mantle due to seawater invasion. These faults are seismically active, given that their geometries are consistent with the focal mechanisms of intraplate earthquakes and microearthquakes. The thrust faults appear to extend landward to a high-density dome within the accretionary prism off the Kii Peninsula. Because the dome and the associated thick accretionary prism are expected to generate high friction at the plate interface due to their large vertical load, the intraoceanic thrusts are likely to have grown with ongoing subduction. Furthermore, because the geometry of the fault system we identified off the Kii Peninsula has characteristics similar to faults at Zenisu Ridge east of our study area, the thrusts observed in the study area may be considered to be the westward continuation of those at Zenisu Ridge. Since the Euler rotation pole of relative motion between the Philippine Sea plate and Zenisu Ridge is consistent with the high-density dome off the Kii Peninsula, we interpret the high-density dome as well as Kashinosaki Knoll as a westward termination of the Zenisu compression zone.

AB - We identified widely distributed thrust and strike-slip faults within subducting oceanic crust in the Nankai Trough, southeast of the Kii Peninsula, Japan, on the basis of 2D and 3D seismic reflection data. The seafloor seaward of the trough axis is deformed by displacement on these intraoceanic reverse faults, producing topographic highs (part of Kashinosaki Knoll). Because the thrust faults extend to the Moho and offset the Moho reflection, they may be related to serpentinization of the mantle due to seawater invasion. These faults are seismically active, given that their geometries are consistent with the focal mechanisms of intraplate earthquakes and microearthquakes. The thrust faults appear to extend landward to a high-density dome within the accretionary prism off the Kii Peninsula. Because the dome and the associated thick accretionary prism are expected to generate high friction at the plate interface due to their large vertical load, the intraoceanic thrusts are likely to have grown with ongoing subduction. Furthermore, because the geometry of the fault system we identified off the Kii Peninsula has characteristics similar to faults at Zenisu Ridge east of our study area, the thrusts observed in the study area may be considered to be the westward continuation of those at Zenisu Ridge. Since the Euler rotation pole of relative motion between the Philippine Sea plate and Zenisu Ridge is consistent with the high-density dome off the Kii Peninsula, we interpret the high-density dome as well as Kashinosaki Knoll as a westward termination of the Zenisu compression zone.

UR - http://www.scopus.com/inward/record.url?scp=84879795641&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84879795641&partnerID=8YFLogxK

U2 - 10.1016/j.tecto.2013.03.014

DO - 10.1016/j.tecto.2013.03.014

M3 - Article

AN - SCOPUS:84879795641

VL - 600

SP - 52

EP - 62

JO - Tectonophysics

JF - Tectonophysics

SN - 0040-1951

ER -