Spiess -- The recommended project will develop and deploy two wireline-deployable, new-generation instrumented borehole seals (Circulation Obviation Retrofit Kits or CORKs) that will integrally contain instrumented multi-packers. These integrated systems will be fully deployable and recoverable by the Marine Physical Lab, Scripps Institution of Oceanography wireline Control Vehicle, making installation and recovery of these next-generation CORKs possible by ships of convenience rather than the ODP drillship JOIDES Resolution. These two systems will be installed within Hole 504B and the nearby Hole 896A to measure in-situ hydrogeological fluid flow and processes within the upper oceanic crust on the south flank of the Costa Rica Rift. Development of this wireline system fulfills the two principle recommendations for future CORK development proposed by the December, 1997 JOI/USSP-sponsored workshop on "Advanced CORKs"- that of 1) independent sealing and monitoring of multiple formations zones; and 2) maximizing wireline access to sealed boreholes. ***