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doi:10.2204/iodp.proc.338.106.2014

Site C00211

M. Strasser, B. Dugan, K. Kanagawa, G.F. Moore, S. Toczko, L. Maeda, Y. Kido, K.T. Moe, Y. Sanada, L. Esteban, O. Fabbri, J. Geersen, S. Hammerschmidt, H. Hayashi, K. Heirman, A. Hüpers, M.J. Jurado Rodriguez, K. Kameo, T. Kanamatsu, H. Kitajima, H. Masuda, K. Milliken, R. Mishra, I. Motoyama, K. Olcott, K. Oohashi, K.T. Pickering, S.G. Ramirez, H. Rashid, D. Sawyer, A. Schleicher, Y. Shan, R. Skarbek, I. Song, T. Takeshita, T. Toki, J. Tudge, S. Webb, D.J. Wilson, H.-Y. Wu, and A. Yamaguchi2

Background and objectives

During Integrated Ocean Drilling Program (IODP) Expedition 338, a slope basin seaward of the megasplay was logged and cored at Site C0021. The slope basin, characterized in 3-D seismic data by stacked mass transport deposits (MTDs) (Strasser et al., 2011), was drilled and sampled in IODP Hole C0018A during IODP Expedition 333 and logged during Expedition 338 (Figs. F1, F2, F3) (Expedition 333 Scientists, 2012a) to establish the stratigraphy of a Quaternary mass-movement event and to sample the distal part of a thick MTD for analyzing its rheological behavior to constrain sliding dynamics and tsunamigenic potential. Site C0018 was drilled at a location where the MTD bodies wedge out and basal erosion is minimal.

During Expedition 338, logging while drilling (LWD) and coring to 294 and 194.5 meters below seafloor (mbsf), respectively, were conducted at Site C0021 (proposed Site NTS-1C) as contingency operations. This site is located ~2 km northwest of Site C0018 at a more proximal site for the MTDs analyzed at Site C0018 (Figs. F2, F3, F4). Therefore, LWD and coring at Site C0021 provided additional information on the nature, provenance, and kinematics of MTDs. By combining data from drilling and postexpedition laboratory experiments on samples from Sites C0021 and C0018 (see the “Site C0018” chapter [Strasser et al., 2014c]), we will improve our understanding of dynamics of submarine landslides as it relates to their tsunamigenic potential.

Hole C0021B core processing and measurements were divided into two phases: shipboard and shore based. The lack of ship time to completely process Hole C0021B cores on board during Expedition 338 dictated that only whole-round examinations could be performed; all remaining sampling tasks and analyses were deferred to a shore-based sampling party at the Kochi Core Center (KCC). Selected personnel from the science party, with some shore-based researchers, met at KCC in Kochi, Japan, from 25 to 30 April 2013 to participate in the sampling party and complete the site chapter reports.

1 Strasser, M., Dugan, B., Kanagawa, K., Moore, G.F., Toczko, S., Maeda, L., Kido, Y., Moe, K.T., Sanada, Y., Esteban, L., Fabbri, O., Geersen, J., Hammerschmidt, S., Hayashi, H., Heirman, K., Hüpers, A., Jurado Rodriguez, M.J., Kameo, K., Kanamatsu, T., Kitajima, H., Masuda, H., Milliken, K., Mishra, R., Motoyama, I., Olcott, K., Oohashi, K., Pickering, K.T., Ramirez, S.G., Rashid, H., Sawyer, D., Schleicher, A., Shan, Y., Skarbek, R., Song, I., Takeshita, T., Toki, T., Tudge, J., Webb, S., Wilson, D.J., Wu, H.-Y., and Yamaguchi, A., 2014. Site C0021. In Strasser, M., Dugan, B., Kanagawa, K., Moore, G.F., Toczko, S., Maeda, L., and the Expedition 338 Scientists, Proc. IODP, 338: Yokohama (Integrated Ocean Drilling Program). doi:10.2204/iodp.proc.338.106.2014

2Expedition 338 Scientists’ addresses.

Publication: 13 January 2014
MS 338-106