Journal of The School of Marine Science and Technology,Vol.8 No.2
Development of magnetic exploration tools for seabed mineral resources
−Performance test in R/V Yokosuka YK09-09 cruise−
Makoto HARADA, Keizo SAYANAGI, Nobuhiro ISEZAKI, Takafumi KASAYA,
Takao SAWA, Miho ASADA, Noriko TADA, Hiroshi ICHIHARA,
Tada-nori GOTO, Yoshifumi NOGI, Nobuhito ONISHI and Jun MATSUO
Abstract
The authors have developed new precise exploration tools for seabed resources by electrical and magnetic
method in order to estimate accurate abundance of those resources. The exploration tools will be mounted underwater
platforms such as deep-tow system, ROV (Remotely Operated Vehicle), and AUV (Autonomous Underwater
Vehicle). In July, 2009, we carried out the R/V Yokosuka cruise in Kumano-nada, off Kii Peninsula, Japan, in order
to investigate the performance of developed equipments for magnetic exploration. We mounted two flux-gate
magnetometers and an Overhauser magnetometer on the deep-tow (DT) system and AUV Urashima. This paper will
present the summary of the test by the AUV. In the test, we used a magnetic target which is consisted of iron bars
and 50 neodymium magnets. The magnetic target was put into water and set at the depth of 2,058 meters. The
navigation of AUV was performed at height of 20-30 meters in the area with a radius of about 300 meters. After the
effects of the magnetization of platform were properly eliminated, the two flux-gate magnetometers successfully
detected prominent magnetic anomaly produced by the magnetic target. We could understand the efficiency of our
system, restrictions of navigation and their suitable operation, and technical problems which are related to some
kinds of noise component. Note that this project has been supported by the Ministry of Education, Culture, Sports,
Science & Technology (MEXT).