Sustained Observations of Subseafloor Pressures at ODP Advanced CORKs at the Nankai Trough Accretionary Prism

University Of Miami, Coral Gables FL

Investigators

Abstract

Recent installation of a well-head bridge plug at the A(advanced)CORK site in the Nankai Trough now permits continued monitoring of pressures with superior resolution in geological formations of a subduction zone (upper basement of incoming plate, plate boundary fault itself, and overlying sediments). This important time series of pressure measurements will be made from two ACORKs deployed during IODP leg 196: 1) a reference hole (1173B) through the sediment column in the oceanic plate and 2) at a deep site (hole 8081) at the frontal thrust of an accretionary prism. From these measurements relationships between subseafloor fluid pressures, fluid flow, and tectonic strain events will be made. Broader Impacts: Relationships between subseafloor pressures and earth quake cycles have societal relevance. The research wiIl support graduate research, strengthen international collaborations between RSMAS-JAMSTEC-GSC, and make good use of existing ODP observatories such as ACORKs