Accelerating Seafloor Uplift of Submarine Caldera Near Sofugan Volcano, Japan, Resolved by Distant Tsunami Recordings

Abstract On 8 October 2023 UTC, significant tsunamis were observed around Japan without any major tsunamigenic earthquake, associated with a series of 14 successive minor earthquakes (mb = 4.5–5.4) near Sofugan in the Izu‐Bonin Islands. To examine the cause of this tsunami, we estimated the horizont...

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Bibliographic Details
Main Authors: Tatsuya Kubota, Osamu Sandanbata, Tatsuhiko Saito, Takanori Matsuzawa
Format: Article
Language:English
Published: Wiley 2024-06-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1029/2024GL108415
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Summary:Abstract On 8 October 2023 UTC, significant tsunamis were observed around Japan without any major tsunamigenic earthquake, associated with a series of 14 successive minor earthquakes (mb = 4.5–5.4) near Sofugan in the Izu‐Bonin Islands. To examine the cause of this tsunami, we estimated the horizontal locations of the tsunami source and temporal history of the seafloor displacement, using the tsunami data recorded by the ocean‐bottom pressure gauges >∼600 km away. Our results showed the main tsunami source was an uplift located at a caldera‐like bathymetric feature near Sofugan, suggesting the involvement of caldera activity in the tsunami generation. The total seafloor uplift was estimated as ∼4 m, and the uplift amount of each event gradually increased over time, reflecting an accelerating occurrence of volcanic unrest of the submarine caldera within only a few hours.
ISSN:0094-8276
1944-8007