International Ocean Discovery Program; Expedition 380 scientific prospectus; NanTroSEIZE Stage 3; frontal thrust long-term borehole monitoring system (LTBMS)

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doi: 10.14379/iodp.sp.380.2017
Author(s): Becker, Keir; Kinoshita, Masataka; Toczko, Sean
Author Affiliation(s): Primary:
University of Miami, Department of Marine Geosciences, Miami, FL, United States
Other:
University of Tokyo, Japan
Japan Agency for Marine-Earth Science and Technology, Japan
Source: Scientific Prospectus (International Ocean Discovery Program), Vol.380, 14p. Publisher: International Ocean Discovery Program, College Station, TX, United States. ISSN: 2332-1385
Note: In English. 53 refs.
Summary: The Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) program is a coordinated, multiexpedition drilling project designed to investigate fault mechanics and seismogenesis along subduction megathrusts through direct sampling, in situ measurements, and long-term monitoring in conjunction with allied laboratory and numerical modeling studies. The fundamental scientific objectives of the NanTroSEIZE drilling project include characterizing the nature of fault slip and strain accumulation, fault and wall rock composition, fault architecture, and state variables throughout the active plate boundary system. International Ocean Discovery Program (IODP) Expedition 380 will deploy a permanent long-term borehole monitoring system (LTBMS) in a new cased hole at Site C0006 above the frontal thrust, where previous expeditions have conducted logging-while-drilling and coring operations. This deployment will be the third borehole observatory deployed as part of the NanTroSEIZE program, and it will extend the existing NanTroSEIZE LTBMS network seaward to include the frontal thrust region of the Nankai accretionary prism. This expedition will cover a period of 40 days, beginning on 12 January 2018 and ending on 24 February. The LTBMS sensors will include seafloor reference and formation pressure sensors, a thermistor string, a broadband seismometer, a tiltmeter, a volumetric strainmeter, geophones, and accelerometers. The casing plan does not include a screened interval for this LTBMS; the monitoring zone will be isolated from the seafloor by a swellable packer (inside the casing) and cement at the casing shoe. This LTBMS will be later linked to the Dense Oceanfloor Network System for Earthquakes and Tsunamis (DONET) submarine network. This Scientific Prospectus outlines the scientific rationale, objectives, and operational plans for Site C0006. A congruent "NanTroSEIZE Investigation at Sea" will convene researchers aboard the D/V Chikyu to use the latest techniques and equipment to reexamine cores, shipboard measurement data (including X-ray computed tomography scans), and logging-whiledrilling data collected during NanTroSEIZE Stage 1 in 2007.
Year of Publication: 2017
Research Program: IODP Integrated Ocean Drilling Program
IODP2 International Ocean Discovery Program
Key Words: 07 Marine Geology and Oceanography; 20 Geophysics, Applied; Asia; Boreholes; Cores; Drilling; Earthquakes; Expedition 380; Far East; Faults; Geophysical methods; Geophysical profiles; Geophysical surveys; Honshu; IODP Site C0006; Integrated Ocean Drilling Program; International Ocean Discovery Program; Japan; Kii Peninsula; Marine drilling; Marine sediments; Monitoring; NanTroSEIZE; Nankai Trough; North Pacific; Northwest Pacific; Observatories; Pacific Ocean; Planning; Plate convergence; Sediments; Seismic methods; Seismic profiles; Subduction zones; Surveys; Well logs; West Pacific
Coordinates: N330100 N330200 E1364800 E1364800
Record ID: 2017072977
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