ディジタル圧力変換器を利用した,新しい長波計測装置(ERI-V型津波計)が,江の島,伊豆大島両津波観測所に設置された.この装置により,サンプリング間隔30secで,1/10mm単位,6桁の数値として海水位のデータが,フロッピーディスクに記録される.またO～+5mの潮汐と,±50cmの長周期波のアナログ記録が,2ペンレコーダーによって得られる.時平均,日平均潮位,24時間パワースペクトルが計算され,ディジタルプリンターに印刷される.現在までに得られた記録の解析処理の二,三の例が示されるが,今後のデータの蓄積によって,海岸付近の長周期海洋波の性質を一層明らかにできるものと期待される.
New instruments for measuring long-period ocean waves were installed at the Enoshima Tsunami Observatory in March 1980 and at the Izu-Oshima Tsunami Observatory in March 1981. A quartz-crystal resonator applying the principle of piezoelectric excitation is used as the water pressure transducer for measurements of sea-surface variation. Values of sea surface elevation calculated from the transducer's output are succesively stored at 30 second intervals to one of a pair of IC memories which are alternatly used every other day. The data on the memory, which consists of 2880 samples every day and can be automatically or manually copied on a floppy disk to preserve them the next day, is expressed by integers of six figures in 0.1 milli-meters. Tide data (0-5 m) obtained by low-pass filtering of 3 min and long-period wave data (±50 cm) obtained by high-pass filtering of 180 min are converted to analog signals and recorded by a two-pen recorder as a monitor. Hourly and daily mean sea levels and power spectrum for the 24 hours data of long-period waves are computed and printed out by a digital printer. These instruments are operating quite well at both tsunami observatories. A small tsunami (about 10 cm) accompanying the earthquake on Jan. 19, 1981 was observed at Enoshima. Spectra of long-period variations of the sea surface are obtained every day and have been analyzed as a clue to finding the general feature of shallow water oscil- lations. It is expected that the data accumulated by this instrument will elucidate the origin of generation and the mechanism of long-period sea surface variations.
雑誌名
東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo
巻
56
号
3
ページ
571 - 585
発行年
1982-01-08
ISSN
00408972
書誌レコードID
AN00162258
フォーマット
application/pdf
日本十進分類法
453
出版者
東京大学地震研究所
出版者別名
Earthquake Research Institute, University of Tokyo
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津波観測所に設置された新しい長波計測装置(ERI-V型津波計)
ji0563007.pdf
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