Long term continuous monitoring of hydrogeologic properties in instrumented boreholes
Project Manager & Lead Scientist: Hans Jannasch
Lead Scientist: Geoff Wheat
This will be the last year of a collaborative, four-year NSF/ODP-funded project to study sediment processes within the subduction zone off Costa Rica by using MBARI-developed downhole OsmoSamplers to continuously monitor porewaters within the subducting sediments. This grant is helping to transition the OsmoSampler technology to the outside community and testing the newly-developed directional OsmoFlowmeter.
In September - October 2002, two boreholes were drilled down to the decollemont, up to 800 meters below the seafloor on both sides of the Costa Rican Subduction Zone. The holes (ODP 1253 and 1255) were outfitted with custom pressure-maintaining CORK-II's containing OsmoSamplers, OsmoFlowmeters, and P/T sensors. This year we will recover the samplers and install a more easily accessible downhole system to simplify future turn-arounds. In this last year of the project, we expect to be involved in data analysis, manuscript writing, and preparing another NSF proposal to continue work at these boreholes.