[A-OS21] 全球海洋観測システムの現状・成果と将来：ニーズへの適合と発展

[AOS21-P06] Three-year seismic observation by hydrophone floats

*大林 政行¹、杉岡 裕子^2,3、吉光 淳子¹、Simon Joel⁴ (1.独立行政法人海洋研究開発機構 海域地震火山部門、2.神戸大学海洋底探査センター、3.神戸大学理学研究科惑星学専攻、4.Department of Geosciences, Princeton University)

キーワード：フロート、ハイドロフォン、太平洋プルーム、西之島、地震観測

An international joint seismic observation project using autonomous float instrument (MERMAID) started from 2018. More than 50 MERMAID instruments were deployed in the south Pacific to study the mantle beneath the South Pacific Superswell, broad seafloor anomalously elevated and concatenated by several volcanic island (hot spot) chain. The MERMAID is an autonomous robotic float equipped with a hydrophone and drifts passively at 1,500–2,000 m depth until an earthquake signal is detected. 9 Japanese MERMAIDs out of them were deployed in the winter and summer of 2019. We will report on the current data set and show that these signals are of sufficient quality for high-resolution tomographic inversion.
Additionally, we launched two MERMAIDs to observe the seismic signals from submarine volcano in the Bonin region in December, 2020. We will discuss the availability of the MERMAID to monitor seafloor volcano activities.