Drilling Vessel Chikyu: Status, Capabilities, and Current Operations

The Deep Sea Drilling Vessel Chikyu is a state-of-the-art drilling platform that can reach geological targets previously inaccessible to scientifi c drilling. This 210-m-long, 57,000-ton vessel comes equipped with a 121-m-tall drilling derrick, a fully integrated riser drilling system and blow-out preventer (BOP), and a highly automated drill fl oor system that runs effi ciently and safely with a small number of operating personnel. The Chikyu is fl exible enough to allow both riser and riserless operations, depending on the scientifi c and technical requirements of a given expedition

The First D/V Chikyu IODP Operations: Successful Drilling and Coring During NantroSEIZE Stage 1 Expeditions

The Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) is a multi-expedition IODP drilling project aimed at drilling, coring, logging, and instrumenting the seismogenic zone of an active subduction margin , in a region thought to generate megathrust earthquakes of magnitude >8.0 on the moment-magnitude scale (Tobin and Kinoshita, 2006). The Nankai Trough, offshore of the Kii Peninsula, Honshu, Japan (Fig. 1) was chosen as the location for thisproject based on a number of scientific drilling proposals to IODP. These reviewed existing drilling data in the region, the long-term historical and recent record of great earthquakes, the social and societal relevance of the area, and the accessibility of the seismogenic zone to present drilling technology. The first stage of this multi-stage project was intended to accomplish a broad characterization of the shallow geology, geophysics, physical properties, heat flow, and fluid flow in a transect across the downgoing Philippine Sea Plate, the toe of the Nankai accretionary prism, the megasplay fault zone region on the continental slope, and the Kumano Basin that lies between the accretionary prism and the KiiPeninsula, on the continental shelf (Fig. 2)