| Co-Investigator(Kenkyū-buntansha) |
KANAZAWA Toshihiko The University of Tokyo, Earthquake Research Institute, Professor, 地震研究所, 教授 (30114698)
ISHII Teruaki The University of Tokyo, Ocean Research Institute, Associate Professor, 海洋研究所, 助教授 (80111582)
TOKUYAMA Hidekazu The University of Tokyo, Ocean Research Institute, Professor, 海洋研究所, 教授 (10107451)
GAMO Toshitaka Hokkaido University, Graduate school of Science, Professor, 理学部, 教授 (70143550)
FUJIMOTO Hiromi Tohoku University, Research Center for Prediction of Earthquakes and Volcanic Eruptions, Professor, 大学院・地震火山噴火予知研究観測センター, 教授 (50107455)
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| Research Abstract |
The purpose of the project is to understand the mid-ocean ridge process at ultra-slow spreading system in the Arctic Ocean. We conducted an international and interdisciplinary cruise in the second year of the project and obtained high-resolution sonar images along the ultra-slow spreading ridge as well as other datasets.
The pre-cruise meetings were held in St. Petersburg in early 2000, and the original science plan was devised to focus research at the Knipovich Ridge using the R/V Professor Logachev (VNIIO, St. Petersburg, Russia, 5620 t). The research strategy consists of an along-axis towing of deep-tow side scan sonar with additional self-recording instruments (light scattering sensor, CTD, magnetometer and pH meter), geophysical measurements (magnetics, heat flow, seismicity) and bottom and water sampling. Scientists from Japan, Russia, USA, UK, Norway, China, Taiwan and Korea participated the cruise. During the cruise on the Knipovich Ridge (Knipovich-2000 cruise), we acquired a 400 km-long profile of the axial valley, 〜75% of the ridge. We detected a few thermal and chemical anomalies along the sonar profile, indicating the existence of the hydrothermal activity. Rock and sediment samples were also collected. We deployed 10 ocean bottom seismometers to detect micro earthquakes in the volcanically active area and recovered them after one-month observation.
The last year of the project (2001) was devoted to analyze the data and to prepare publications. Preliminary results were reported in the Japan Earth and Planetary Science Joint Meeting (Tokyo, 2001). An international post-cruise meeting was held in St. Petersburg, in November, 2001, to synthesize the results. A paper on the segmentation of the ridge has been submitted to an international journal and other results will be submitted to the appropriate journals within a year.
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