This Japanese vessel has added a deep-drilling capability to scientific ocean drilling. Chikyu, operated by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Center for Deep Earth Exploration, can handle up to 12 kilometers of drill string and has a riser capable of drilling in 2.5 kilometers of water. Chikyu’s on-board laboratory is equipped with a suite of state-of-the-art analytical equipment for core analyses (including a CT scanner). Chikyu’s riser technology, which provides mud circulation to clear drill cuttings and stabilizes the borehole, enables deep penetration into unstable formations, allowing sampling of active fault zones and downhole measurements of pore pressure and stress. Since 2005, Chikyu has drilled deep holes in the Nankai subduction zone off the eastern cost of Japan, an area with a 1,400-year-long recorded history of magnitude 8-plus earthquakes recurring at 120-year intervals. Chikyu was damaged by the tsunami during the 2011 Tohoku earthquake but has been repaired and is now drilling again.
The Future
The scientific ocean drilling community, through NSF and the other international IODP funding agencies, is actively pursuing funding to expand this ambitious exploration program beyond 2013. The international scientific drilling community has developed a scientific plan for the next decade. The new plans set forth a program to conduct expeditions that will target pressing questions about climate and ocean change, biodiversity and the limits of deep life, and the processes associated with geohazards on human time scales.
Achieving these goals will require a wide variety of drilling capabilities, in-situ measurements and long-term monitoring capabilities, including deep drilling up to 7 kilometers into the ocean floor, at continental margins, and in extreme environments such as shallow water (less than 100 meters) and the Arctic.
No single drilling platform or coring technique can accomplish this task. The next phase of ocean drilling, if successfully funded, will continue to use the two principal platforms, the JR and the Chikyu, complemented by the use of mission-specific platforms. With a planned development of Chikyu’s riser capability from 2.5 kilometers to more than 4 kilometers of water depths, along with new generations of advanced CORKs to isolate and sample multiple subsurface zones and continued development of coring and logging tool, the new program will have the necessary technology to continue its unparalleled exploration of the Earth beneath the sea. https://www.sea-technology.com
No comments:
Post a Comment