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doi:10.2204/iodp.sp.315add.2007

Changes to the drilling program

Contingency sites added

Two new contingency sites have been added and approved by the Integrated Ocean Drilling Program Environmental Pollution and Safety Panel and Site Survey Panel based on

1. Newly recognized scientific targets determined from 3-D seismic data,


2. Anticipated extra contingency time, and


3. The need for alternate sites in areas where drilling/weather/current conditions may be better than at primary sites.

Proposed contingency Sites NT2-05A and NT2-10A are located on the trench slope, between proposed Sites NT2-01D and NT1-03B (Table T1). The details of these sites are as follows:

• Proposed Site NT2-05A: 33°12.433′N 136°43.867′E, water depth = 2839 m, total depth = 275 meters below seafloor (mbsf)


• Proposed Site NT2-10A: 33°12.830′N 136°43.600′E, water depth = 2758 m, total depth = 325 mbsf.

See Figures F1, F2, and F3 for location, seismic data, and borehole position/depth information.

Both sites are available for contingency operations for both logging-while-drilling and coring/measurement operations using the hydraulic piston coring system. The scientific significance of the new contingency sites is related to the recognition that significant amounts of material shed from uplifted thrust blocks transported to the surface by faulting on the megasplay system have been deposited on older thrust blocks downslope toward the trench. Cores taken in these sedimentary packages may reveal the timing and relative age of past fault motions through the identification of provenance and age of deposited material and the age across any disconformities between newly deposited sediments and older uplifted fault blocks.

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