The CHIKYU is operated by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) in partnership with the Integrated Ocean Drilling Program. The expedition began with drilling operations at the Kumano Basin, off the Kii Peninsula on May 10, 2009.
Expedition 319 marks the first riser drilling in the history of the scientific ocean drilling program, and the first subseafloor observatory operations for NanTroSEIZE. The expedition was led by four Co-Chief Scientists: Eiichiro Araki, Research Scientist of JAMSTEC; Timothy Byrne, Professor of the University of Connecticut, USA; Lisa McNeill of the University of Southampton, UK; and Demian Saffer, Associate Professor of Geosciences at The Pennsylvania State University, and was joined by scientists from eight countries.
Expedition 319 conducted drilling operations at three drill sites in the Nankai Trough. At the first Site C0009, located directly above the seismogenic zone where great earthquakes occur, scientists conducted the first riser drilling in IODP history and successfully drilled down to a depth of 1,603.7 meters beneath the sea floor. Riser-based drilling allowed the scientists to conduct several scientific operations unprecedented in IODP, including 12 successful measurements of stress and pore fluid pressure in the subsurface using the dynamic formation testing tool, a two ship seismic experiment using a dense seismic array in the borehole, real-time mud gas analysis, and laboratory analyses of drill cuttings that are generated as the drill bit penetrates through the formation. In addition, 57.87 meters of core sample (a cylindrical geological sample) were obtained from depths between 1,510 and 1,593.9 meters below the seafloor. The scientific party developed several new techniques for analyzing these materials, which will be essential for future riser-based drilling.
At a second borehole (Site C0010), drilling crossed one of the major faults in the plate boundary, known as the mega-splay fault, at a depth of about 400 meters below the seafloor. This fault is a prime candidate for tsunami generation, and may have slipped in historical great earthquakes. During the drilling operation, scientists documented rock physical properties and gained information about stresses in the formation. The borehole was then cased and utilized for observatory operations for future long-term borehole monitoring. These included lowering of test instruments, as well as emplacement of a temporary sensor package that will monitor conditions in the fault zone in the next few years.
The new data from Expedition 319 indicate that the stresses in the upper plate reflect the forces acting on the earthquake generating fault zones below. The direction of the maximum stresses follows the direction of tectonic plate motion in most of the region, but rotates drastically in a very narrow region above the mega-splay fault. In addition, the rock units, and in particular the ages of the rocks obtained by examining microfossils and the sediment types observed in the drill cuttings, provide new constraints on the geologic history of the major fault zone and its activity level.
The CHIKYU is now berthed at the Port of Yokkaichi, where it is preparing for IODP Expedition 322 scheduled to sail on Sept. 4. Operations will include core sampling and logging for all layers in the formation, with an aim to better understand the initial state of geological input materials before they are entering the seismogenic zone.
The Integrated Ocean Drilling Program (IODP) is an international marine research drilling program dedicated to advancing scientific understanding of Earth by monitoring, sampling, and instrumenting subseafloor environments. Through multiple platforms, preeminent scientists explore IODP principal themes: the deep biosphere, environmental change, and solid Earth cycles. IODP has operated since October 2003, funded jointly by the Japan Ministry of Education, Culture, Sports, Science and Technology and the U.S. National Science Foundation. Additional support is provided by the 17-member European Consortium of Ocean Research Drilling, the People's Republic of China, the Republic of Korea, Australia, India, and New Zealand. http://www.iodp.org
To learn more about NanTroSEIZE, visit http://www.jamstec.go.jp/chikyu/eng/Expedition/NantroSEIZE/index.html or access the NanTroSEIZE media kit at http://www.iodp.org/NanTroSEIZE-Media-Kit/3
Find more information on riser drilling at http://www.iodp.org/riser-vessel/.Contacts:
Raesah Et'Tawil | EurekAlert!
Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute
Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder
Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
09.12.2016 | Life Sciences
09.12.2016 | Ecology, The Environment and Conservation
09.12.2016 | Health and Medicine