With its acclaimed past surveys, ever greater expectations are placed on the CHIKYU worldwide.
A preliminary survey for drilling into the mantle off Hawaii will start this summer, and the CHIKYU will set sail to take on new challenges on the world’s oceans.
| Interviewee: Deputy Director Dr. Shin’ichi Kuramoto Planning and Coordination Department, Center for Deep Earth Exploration |
The world’s scientists gather to discuss the future of the CHIKYU
What kind of research will the CHIKYU engage in in the next 10 years? The inter- national workshop CHIKYU+10 was held in April 2013 to pool knowledge and discuss this. Approximately 400 scientists from 20 different countries and regions took part. A great many people, especially young scientists, attended in numbers that exceeded our expectations, and we experienced first-hand the high acclaim which past surveys by the CHIKYU are held in and the international recognition they are receiving. In future, the CHIKYU will broaden its field of activity to include all the world’s oceans.
The most important themes covered at the CHIKYU+10 workshop were ‘seismogenic zones’, ‘mantle survey’, ‘subseafloor biosphere’, ‘continent formation’, and ‘environment change in the earth’s history’. What we want to focus our efforts on out of these is, of course, the challenge of reaching the mantle. Drilling to great depths beneath the sea floor and recovering samples from the mantle, which nobody in the world has as yet been capable of doing: it is the main reason why the CHIKYU was built in the first place.
Sailing the world's oceans to reach the as yet unexplored mantle
A preliminary survey to drill into this mantle will start this summer off the Hawaiian coast. Apart from Hawaii, there are two other candidate fields for the mantle survey, namely areas off the Costa Rican coast and off Mexico.
As this is an unprecedented challenge in the history of science, there naturally is a number of barriers to overcome. The ocean in all of these three areas is close to 4,000 m deep, and there is no previous example of riser drilling at such great (underwater) depths. On top of that drilling is needed for a further 6,000 m or more beneath the seafloor, so that the total length of the drill pipe will extend to more than 10 km. New long-life drill bits and observational instruments that can cope with the inhospitable environment are also required. We believe however that these kinds of technical breakthroughs are by no means impossible.
As with Einstein’s relativity theory, or the moon landing by the Apollo 11, I think that if the CHIKYU succeeds in recovering a sample from the mantle, it may well lead to great outcomes that could usher in a new epoch in the history of science.
The mantle is mainly made up of peridotite, and its convection is the motive power behind continental drift and volcanic activity etc. Moreover, the existence of massive amounts of carbon and water that are contained in the mantle and circulate inside the earth have recently attracted the attention of scientists. If we can investigate the mantle directly, that should contribute substantially to clarifying the origin and structure of the earth.
Investigating the mantle is also intimately connected to the other important themes previously mentioned. To reach the mantle, we will pass through the borders of the subseafloor biosphere, and should also produce results for the study of crust formation and transitions in the earth’s history. Moreover, as this is a theme that will also lead to clarifying the mechanisms in the generation of large earthquakes, we will continue to engage in that in the same way as before.
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