Large mass transport deposits in Kumano Basin, Nankai Trough, Japan

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doi: 10.1007/978-3-319-20979-1_37
Author(s): Moore, Gregory F.; Strasser, Michael
Author Affiliation(s): Primary:
University of Hawaii, Department of Geology and Geophysics, Honolulu, HI, United States
Eidgenössische Technische Hochschule Zurich, Switzerland
Volume Title: Submarine mass movements and their consequences; 7th international symposium
Volume Author(s): Lamarche, Geoffroy, editor; Mountjoy, Joshu J.; Bull, Suzanne; Hubble, Thomas; Krastel, Sebastian; Lane, Emily M.; Micallef, Aaron; Moscardelli, Lorena; Mueller, Christof; Pecher, Ingo A.; Woelz, Susanne
Source: Advances in Natural and Technological Hazards Research, Vol.41, p.371-379; 7th symposium on Submarine mass movements and their consequences, Wellington, New Zealand, Nov. 1-4, 2015, edited by Geoffroy Lamarche, Joshu J. Mountjoy, Suzanne Bull, Thomas Hubble, Sebastian Krastel, Emily M. Lane, Aaron Micallef, Lorena Moscardelli, Christof Mueller, Ingo A. Pecher and Susanne Woelz. Publisher: Springer, Dordrecht, Netherlands. ISSN: 1878-9897. ISBN: 978-3-319-20979-1
Note: In English. 22 refs.; illus., incl. geol. sketch maps, sects., block diag.
Summary: Large-scale landsliding is a common process in the Kumano Forearc Basin of the Nankai Trough accretionary prism. We use a 3D seismic data volume to map the seafloor reflection, which shows that there are two surficial landslides, one rotational slump ∼3.4 km wide, 1.8 km long and 150 m thick and one disintegrative slide that has left a seafloor scar ∼>3.65 km wide, 2.6 km long and ∼200 m deep. We see no evidence for any deposits related to the latter in our data, so the entire mass must have been transported as debris flows/turbidites outside the area covered by 3D data. The slump failures occurred along a bedding plane that dips ∼5-7° landward, but the disintegrative landslide has a gently-dipping base and is associated with steep normal fault scarps. Several large subsurface mass-transport deposits (MTD)s are mapped in the 3D seismic data--all have slid along single landward-dipping bedding planes. Their bases range in depth from 140 to 700 m below sea floor (mbsf). The thickest MTD is ∼6.5 km2×155 m thick, encompassing a volume of ∼1.0 km3. The three other large MTDs range from 0.3 to 0.6 km3 in volume. The toes of the MTDs are imbricated, and the imbricate structure, as imaged in continuity displays, is aligned parallel to the slope. Many less extensive, thinner (<20 m thick) MTDs are also present in the Kumano Basin. Regional seismic-stratigraphy and age-constraints on MTD-correlative seismic reflections drilled at IODP drill Sites C0009 and C0002 reveal that four of the investigated MTDs are younger than 0.3-0.44 Ma, three are 0.44-0.9 Ma, and three others are between ∼0.9 and 1.24 Ma
Year of Publication: 2016
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Accretionary wedges; Asia; Bathymetry; Cenozoic; Debris flows; Expedition 319; Failures; Far East; Faults; Geomorphology; Geophysical methods; IODP Site C0002; IODP Site C0009; Integrated Ocean Drilling Program; Japan; Kumano Basin; Landslides; Mass movements; Mass transport deposits; NanTroSEIZE; Nankai Trough; North Pacific; Northwest Pacific; Ocean floors; Pacific Ocean; Quaternary; Scarps; Sediment transport; Seismic methods; Seismic stratigraphy; Slides; Slumping; Transport; Turbidite; West Pacific
Coordinates: N331800 N331801 E1363801 E1363800
N332728 N332728 E1363209 E1363209
Record ID: 2016091755
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.