海底地震観測から推定される深海底の強い流れ(序報)

概要

論文の詳細を見る
To prove experimentally the former conclusion that the cause of "sinusoidal noise" with the frequency of 2-3 Hz observed by a pop-up ocean bottom seismometer (pop-up OBS) is the Karman vortexes around an antenna produced by the bottom current with a greater speed than 16 cm/sec, a comparative measurement between a pop-up OBS and a bottom current meter was carried out in the Ozuchi Bay. During the above measurement, four OBS's which is the same type as the above were deployed east of the Sanriku coast. The OBS in the bay showed no "sinusoidal noise" greater level than 250 μ kine and the bottom current observed showed a maximum current speed of 9 cm/sec during 15 days. On the contrary, three of four OBS's at depth from 1,000 meter to 1,900 meter showed a large 2.2 Hz "sinusoidal noise" varing with time and place. If the cause for the noise is a bottom current greater than 16 cm/sec, the bottom current at the abyssal slope east of Sanriku coast might be greater than 16 cm/sec. Several other pop-up OBS measurements performed by ERI also showed similar sinusoidal noises suggesting a common feature of large deep-sea bottom currents.
東京大学地震研究所,Earthquake Research Institute, University of Tokyo,東京大学地震研究所の論文
1981-08-31