Texas A&M University, United States

Integrated Ocean Drilling Program Expedition 341S is an engineering expedition dedicated to two separate projects. One is the first deployment of the Simple Cabled Instrument for Measuring Parameters In situ (SCIMPI) on the Cascadia margin. The second is to replace the CORK in Hole 858G for formation pressure monitoring in the Middle Valley axial rift of the Juan de Fuca Ridge. Both installations are to be incorporated into the NEPTUNE Canada observatory network. The SCIMPI is a new observatory instrument designed to study dynamic processes in the subseabed based on a simple and low-cost approach. The SCIMPI was developed to provide, when appropriate, an alternative to CORK subseafloor observatories that can be more complex, costly, and time consuming to install. The SCIMPI makes time series measurements of subseafloor temperature, pressure, and electrical resistivity at several depths that can be tailored for site-specific scientific objectives. The SCIMPI's modular design enables custom configuration based on the study goals and the subseafloor characteristics. The new CORK to be installed in Hole 858G will be constructed with a simplified seal system that has been designed to survive the overpressures and high temperatures at this location. Pressure and temperature data from the refitted hole will complement those from the nearby Hole 857D CORK, which has been in continuous service since 1996, as well as data from seismometers and other instruments that will be part of a multidisciplinary NEPTUNE Canada observatory at this seismically, geodynamically, and hydrothermally active site.