Advanced CORKs for ODP Drilling in the Nankai Trough: Sustained Observations of Subsurface Pressures in an Accretionary Prism

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Becker 00-83156Recommended project is for acquisition and instrumentation costs for two Advanced Circulation Obviation Retrofit Kits (A-CORKs) that will be installed on Ocean Drilling Program (ODP) Leg 196. These will be used for sustained observations of subsurface fluid pressures in three stratigraphic regions of the Nankai Trough subduction zone- the oceanic basement of the subducting plate, the decollement between the accretionary wedge and the subducting crust, and in major faults within the accretionary wedge. The advanced CORKs use multiple packer strings to independently seal off several regions of the borehole, in contrast to the original CORK design that integrated fluid pressure measurements over the entire borehole length. The A-CORKs will also allow for eventual sampling of in-situ fluids. This proposal is part of a larger, multi-national effort that includes Canadian and ODP resources in designing and fabricating the A-CORKs, installation of the A-CORKs and associated, Japanese-funded instrument strings by the ODP JOIDES Resolution drillship, and related logging-while-drilling (LWD) occurring in conjunction on the same cruise. Ship and submersible operations for follow-up data recovery and instrument servicing will be funded by the Japanese technology agency JAMSTEC.***