Proc. IODP | Volume 338 doi:10.2204/iodp.proc.338.105.2014 Strasser, M., Dugan, B., Kanagawa, K., Moore, G.F., Toczko, S., Maeda, L., and the Expedition 338 Scientists Proceedings of the Integrated Ocean Drilling Program, Volume 338 Background and objectives During Integrated Ocean Drilling Program (IODP) Expedition 338, a slope basin seaward of the megasplay fault was logged with logging while drilling (LWD)/measurement while drilling (MWD) at Site C0018. The slope basin, characterized in 3-D seismic data by stacked mass transport deposits (MTDs) (Strasser et al., 2011) was drilled and sampled during IODP Expedition 333 in Hole C0018A (Fig. F1) (Expedition 333 Scientists, 2012a). The primary goals of operations at Site C0018 were to establish the stratig- raphy of Quaternary mass-movement events and to sample the distal part of an exceptionally thick MTD for analyzing its rheo- logical behavior to constrain sliding dynamics and tsunamigenic potential. Site C0018 (proposed Site NTS-1A; water depth = 3084.35 m) is lo- cated ~5 km southwest of IODP Sites C0004 and C0008, which were drilled and cored during IODP Expedition 316 (Screaton et al., 2009) (Figs. F1, F2). Site C0018 is located within a lower slope basin that (1) represents the depocenter for downslope mass transport, (2) is characterized by stacked MTDs that were seismi- cally identified as acoustically transparent to chaotic bodies with ponded geometries (Fig. F2), and (3) includes a large (as thick as 182 m) MTD (Strasser et al., 2011). Hole C0018A was drilled at a location where the MTD bodies wedge out and basal erosion is thought to be minimal. Coring to ~314.15 meters below seafloor (mbsf) allowed sampling of the MTDs across this stratigraphic succession. Sediment cored in Hole C0018A are divided into two lithologic subunits. Lithologic Subunit IA (0–190.65 mbsf) is primarily com- posed of hemipelagic mud (i.e., silty clay) with interbedded vol- canic ash layers and is affected by MTDs, whereas lithologic Sub- unit IB (190.65–313.65 mbsf) is a sandy turbidite sequence (Expedition 333 Scientists, 2012a; Strasser et al., 2012). Six MTDs (numbered 1–6 from top to bottom) ranging in thickness from 50 cm to 61 m are identified within Subunit IA (Expedition 333 Sci- entists, 2012a; Strasser et al., 2012) (Fig. F3). These MTDs are com- posed of chaotic and convolute bedding with intervals of coher- ent bedding and commonly have bases defined by shear zones. A mass-movement event related to deposition of the lowermost and most prominent MTD 6 is younger than 1.05 Ma (because an ash layer immediately below the thick MTD 6 is identified as the one dated on land as 1.05 Ma) but older than 0.85 Ma, as constrained Chapter contents Background and objectives . . . . . . . . . . . . . . . . 1 Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Logging while drilling . . . . . . . . . . . . . . . . . . . . 2 Core-log-seismic integration . . . . . . . . . . . . . . . 5 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 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 C0018. 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.338.105.2014 2 Expedition 338 Scientists’ addresses. Site C0018 1 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. Yamaguchi 2