2025-08-08 東京大学
図：距離が近い観測点での海底温度時系列の比較。
(a,b)距離50-60km程度の観測点のペアを比較している。(a)はほぼ同じ深さ、(b)は異なる深さ。
(c,d)距離40km程度の観測点のペアを比較している。(c)はほぼ同じ深さ、(d)は異なる深さ。
＜関連情報＞
- https://www.iis.u-tokyo.ac.jp/ja/news/4844/
- https://link.springer.com/article/10.1007/s10872-025-00770-y
DONETの海底温度記録における南海トラフ沿いの同相変動 In-phase variation along the Nankai trough in the ocean bottom temperature records of DONET
Tomohiro Inoue,Yusuke Yokota & Tatsuya Kubota
Journal of Oceanography Published:26 July 2025
DOI:https://doi.org/10.1007/s10872-025-00770-y
Abstract
Ocean bottom temperature is affected by waves propagating along the seafloor. Understanding fluctuations in ocean bottom temperature caused by such wave phenomena can enhance the accuracy of geophysical observations. If seafloor seismic observation networks such as the Dense Ocean floor Network system for Earthquakes and Tsunamis (DONET), which was installed for earthquake disaster prevention in the Nankai Trough region, can detect ocean waves generated along the continental slope, they may serve broader multidisciplinary research objectives across various ocean bottom seismic networks. Here, we investigated the spatiotemporal characteristics of ocean bottom temperature data recorded by DONET and identified in-phase wave patterns. Our findings reveal that temperature correlations are more strongly dependent on relative water depths than on the horizontal distances between observation sites. Such in-phase variations observed in DONET thermometers suggest that seafloor seismic networks can indeed detect and assess oceanographic phenomena such as wave propagation. Furthermore, we discuss the implications of such wave activity on the accuracy of distributed acoustic sensing (DAS) data used in geophysical studies, highlighting potential applications of DAS in oceanography and its relevance to crustal deformation observation.
