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| HOME > Expedition > NanTroSEIZE > NanTroSEIZE Exp. 315 |
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IODP Nankai Trough Seismogenic Zone Experiment
Stage 1 Expedition 315 "Megasplay Riser Pilot" |
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OVERVIEW |
| Expedition Number |
Expedition 315 |
| Expedition Prospectus |
Expedition 315, entitled "Megasplay Riser Pilot," is a pilot study for the future deep riser drilling of the megasplay fault in Stage 2. The primary engineering and scientific objectives of this expedition are to obtain geotechnical information needed for well planning of future riser drilling to 3500 meters below seafloor. This site's location is also critical for understanding the nature of the shallow portions of splay faults. The scientific targets of this expedition are deformation mechanics, fault-related fluid source and migration pathways, and correlations between fault activity and slump deposits on the trench slope. |
| Location |
Nankai Trough, Kumano-nada, Offshore Kii peninsula, Japan |
| Duration of Expedition |
From Nov. 16 to Dec. 18 2007 |
| Drilling Vessel |
The Chikyu |
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EXPEDITION SCIENTISTS |
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Juichiro Ashi
University of Tokyo (Japan)
Siegfried Lallemant
University of Cergy-Pontoise (France/ECORD) |
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Summary of drilling result |
Summary of Coring Operation
| Drilling site:C0001(Proposed site:NT2-03) |
| North Latitude:33°14.0’ East Longitude:136°42.0’ |
Hole
Name |
Water
depth |
Core sampling depth
(below seafloor) |
Summary of Result |
| E |
2188.5m |
0m to 118.1m |
Collected samples by Hydraulic Piston Core Sampling System(HPCS) |
| F |
2187.5m |
108.0m to 229.8m
(HPCS)
229.8m to 248.8m
(ESCS) |
Collected samples by Hydraulic Piston Core Sampling System(HPCS) and Extended Shoe Coring System (ESCS) |
| G |
2187.0m |
- |
Abandoned drilling since ROV cable tangled to drill pipe right after starting core sampling by Rotary Core Barrel Sampling System (RCB). |
| H |
2197.0m |
240.0m to 458.0m |
Collected samples by Rotary Core Barrel Sampling System (RCB). Skip coring the difficult portion and tried to collect samples from 600meters below seafloor or deeper, borehole wall was not stable. Moved to next site. |
| I |
2198.5m |
- |
Tried to collect samples by Rotary Core Barrel Sampling System (RCB) from 600mbsf or deeper, but borehole wall was not stable. Moved to next site. |
| Drilling site:C0002(Proposed site:NT3-01) |
| North Latitude:33°18.0’ East Longitude:136°38.0’ |
Hole
Name |
Water
depth |
Core sampling depth
(below seafloor) |
Summary of Result |
| B |
1937.5m |
475.5m to 1057.0m |
Collected samples by Rotary Core Barrel Sampling System (RCB). Abandoned further coring since borehole wall conditions never get any better despite many efforts. |
| C |
1937.1m |
0m to 13.77m |
Collected samples by Rotary Core Barrel Sampling System (RCB). Abandoned further coring since borehole wall conditions never get any better despite many efforts. |
| D |
1937.1m |
0m to 204.0m |
Collected samples by Rotary Core Barrel Sampling System (RCB). Abandoned further coring since borehole wall conditions never get any better despite many efforts. |
*About core sampling system
Hydraulic Piston Core Sampling System (HPCS) : Applied to very soft formations. Stub edgy tip like knife into layers using hydraulic pressure, and collect core without rotate drill bit.
Extended Shoe Coring System (ESCS) : Applied to soft formation that is difficult to collect. Tip of the system can adjust to layers intensity using spring power.
Rotary Core Barrel Sampling System (RCB) : Applied to layers of middle to high intensity. Collect samples while rotating drill bit and scraping layers. Good for consolidated layers with less ruptures.
Drilled only : Zone at where only drilling was operated (no core sampling) in accordance with scientific objectives.
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Expedition 315 Scientific Prospectus |
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