Magnetic anomalies over and around the Japan Trench off Sanriku and the Yamato Bank in the Japan Sea.
Ship borne magnetic surveys were carried out along the Japan Trench off Sankiku Coast and over and around the Yamato Bank in the Japan Sea using a towed proton procession magnetometer. The spacing was about 5 miles. Total magnetic intensiity was observed to the absolute accuracy of 土 10 γ. The positions of observation points were measured by means of Loran system. A magnetic total force distribution chart for the sea was obtained. Substracting the regional trend from the data, an anomaly chart was also drawn. From the observation results, it was found that there was a series of magnetic anomaly of about 500 γ along the Japan Trench in the Pacific Ocean. This means that the magnetic anomaly is related to the structure of the Japan Trench. It also was found that there were positive and negative magnetic anomalies of about 500 γ over and around the Yamato Bank. In this case, the pattern of the anomaly distribution is complicated due to the existence of the sea mounts, including the Yamato Bank and the North Yamato Bank. It seems that the magnetic material causing the anomalies must be embedded quite near the surface of the bank.
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| Format: | Journal Contribution biblioteca |
| Language: | Japanese |
| Published: |
1966
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| Online Access: | http://hdl.handle.net/1834/16411 |
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