Vol.6 No.3 2014

Research paper−158−Synthesiology - English edition Vol.6 No.3 pp.158-165 (Dec. 2013) in Japan. The Basic Act on Ocean Policy was established in 2007, followed by the Ocean Policy Basic Plan and the Marine Energy and Mineral Resources Development Plan in 2008. Under the Marine Energy and Mineral Resources Development Plan, the commercialization of submarine hydrothermal mineral deposits was set for 2018. Also, the situation of the mineral resources changed greatly because of the worldwide increases in resource prices after the global financial crisis in 2007. With such a background, the importance of submarine mineral resource development increased dramatically. The future utilization of these resources depends on the provision of geological information that contributes to the management, maintenance, and development of Japan’s vast exclusive economic zone (EEZ).In April 2012, the United Nations approved the majority of Japan’s application for governance over an extended continental shelf area,[2] which was widely reported by the media. This approval covered an area of approximately 310,000 km2 (Fig. 1), and included the ocean regions of Shikoku Basin, Ogasawara Plateau, Minami-Io-jima Island, and Southern Oki-Daito Ridge. It is expected that these areas will hold significant mineral resources, and sufficient marine geological information is required to identify potential zones of concentration within existing geological structures. Conducting surveys effectively and accelerating the organization of data will therefore serve the national interests of Japan.In the present study, we report the significance and current practices of organizing basic geological information from 1 Introduction“Marine Geological Investigations on the Continental Shelves and Slopes around Japan” is a special research program of the Agency of Industrial Science and Technology started in FY 1974. As part of this project, marine geological surveys were conducted to obtain geological information on ocean regions around Japan and create 1:200,000 marine geological maps. Surveys of the four main islands of Japan (Honshu, Hokkaido, Kyushu, and Shikoku) were completed in FY 2006. The marine geological survey for the region around Okinawa, for which there was no basic geological information, was started in 2008 (hereinafter referred to as the Okinawa Project). In the Okinawa Project, the region around Okinawa-jima Island was surveyed in 3 years from FY 2008 to 2010, and the northern part of the Okinawa Trough was surveyed during the GH11 cruise in FY 2011. The names of the AIST survey cruises are derived from the name of the organization (G stands for Geological Survey of Japan), the name of the survey ship (H for Hakurei Maru No. 2), and the western calendar year in which the survey was conducted. A survey of the ocean region around Okinoerabu-jima, Tokuno-shima, and Amami-oshima islands in Kagoshima Prefecture which began in FY2012 is planned to continue for 4 years. After completion of the large-scale survey of the southern Okinawa Trough, a survey is scheduled of the area around the islands of Southern Ryukyu (Miyako-jima, Ishigaki-jima, and Yonakuni-jima islands).[1]The planned duration of the Okinawa Project overlaps with a major change in policies for marine development and use - Geoinformation for the development of submarine mineral resources-AIST has been conducting marine geological surveys in the Okinawa area to construct geological maps since 2008. The chain of islands extending from Kyushu to Taiwan in the Okinawa area is called the Ryukyu Arc, and was formed with the subduction of the Philippine Sea Plate beneath the Eurasian Plate along the Ryukyu Trench. The Okinawa Trough is a back-arc basin formed behind the Ryukyu Arc. Active submarine volcanoes and hydrothermal phenomena are known to exist in the trough. Because large scale mineral deposits may exist in relation to the geological structures, collecting the marine geological information around the area where submarine mineral resources are expected is very effective for grasping the location of resource-rich zone. Being surrounded by sea, Japan is expected to increase marine utilization within the Exclusive Economic Zone (EEZ) in the future. Methods for developing submarine mineral resources based on the geological phenomena are presented as tools for exploiting fundamental geological information.Marine geological mapping project in the Okinawa area Keywords : Marine geology, geological structures, Okinawa Trough, back-arc basin, marine mineral resources[Translation from Synthesiology, Vol.6, No.3, p.162-169 (2013)]Kohsaku Arai*, Gen Shimoda and Ken IkeharaGeological Survey of Japan, AIST Tsukuba Central 7, 1-1-1 Higashi, Tsukuba 305-8567, Japan *E-mail: Original manuscript received October 2, 2012, Revisions received January 31, 2013, Accepted February 15, 2013


page 25