Sakaguchi, Arito et al. (2011): Episodic seafloor mud brecciation due to great subduction zone earthquakes

Leg/Site/Hole:
IODP 316
Identifier:
2011-097142
georefid
10.1130/G32043.1
doi
Creator:
Sakaguchi, Arito
JAMSTEC (Japan Agency for Marine-Earth Science and Technology), IFREE (Institute for Frontier Research on Earth Evolution), Yokohama, Japan
author
Kimura, Gaku
University of Tokyo, Japan
author
Strasser, Michael
University of Bremen, Germany
author
Screaton, Elizabeth J.
University of Florida, United States
author
Curewitz, Daniel
Syracuse University, United States
author
Murayama, Masafumi
Kochi University, Japan
author
Identification:
Episodic seafloor mud brecciation due to great subduction zone earthquakes
2011
Geology (Boulder)
Geological Society of America (GSA), Boulder, CO, United States
39
10
919-922
The Nankai Trough off southwest Japan has an approximately 1300 yr historical record of great earthquakes, including the most recent, the A.D. 1944 Tonankai (M = 8.2) earthquake. Evaluation of the activity of an individual submarine fault is difficult when only onland observations are available. Submarine core records can pinpoint individual fault activity. Here we present Integrated Ocean Drilling Program (IODP) Nankai Trough Seismogenic Zone Experiment data from the shallow portion. IODP Expedition 316 drilled and cored several holes in the shallow portion of the offshore Tonankai earthquake area, including sites in the hanging wall of a margin-dominating splay fault that has previously been interpreted to have ruptured coseismically during megathrust earthquakes. X-ray computed tomography scanning revealed that the uppermost core at one site contains repeated occurrences of mud breccia. Radioisotope dating of the uppermost mud breccia indicates a deposition time consistent with the 1944 Tonankai earthquake, suggesting that the mud-breccia layers result from episodic brecciation caused by seismic shaking. Mud brecciation provides a potential new tool to reconstruct ancient earthquake history in subduction zones.
English
Serial
Coverage:Geographic coordinates:
North:33.1400
West:136.4300East: 136.4800
South:33.0100
Seismology; Asia; breccia; brecciation; clastic sediments; computed tomography data; cores; coseismic processes; deep-sea environment; earthquakes; Expedition 316; Far East; faults; great earthquakes; Integrated Ocean Drilling Program; Japan; marine environment; marine sediments; mud; Nankai Trough; NanTroSEIZE; North Pacific; Northwest Pacific; Pacific Ocean; paleoseismicity; periodicity; reconstruction; sediments; splay faults; subduction zones; Tonankai earthquake 1944; troughs; West Pacific;
.