Ancient Tsunami Records in the Viscous Remanent Magnetization of Reworked Boulders in the Kingdom of Tonga

Abstract The movement history of boulders is crucial for the reconstruction of paleo‐tsunamis. We report findings from viscous remanent magnetization studies of the boulders on Tongatapu Island, aiming to reconstruct their reworkings. Two boulders exhibited viscous remanence, whereas two larger boul...

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Main Authors: Tetsuro Sato, Norihiro Nakamura, Masahiko Sato, Chie Kato, Kazuhisa Goto, Masashi Watanabe, Kenji Satake, Taaniela Kula
Format: Article
Language:English
Published: Wiley 2024-11-01
Series:Geophysical Research Letters
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Online Access:https://doi.org/10.1029/2024GL110932
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author Tetsuro Sato
Norihiro Nakamura
Masahiko Sato
Chie Kato
Kazuhisa Goto
Masashi Watanabe
Kenji Satake
Taaniela Kula
author_facet Tetsuro Sato
Norihiro Nakamura
Masahiko Sato
Chie Kato
Kazuhisa Goto
Masashi Watanabe
Kenji Satake
Taaniela Kula
author_sort Tetsuro Sato
collection DOAJ
description Abstract The movement history of boulders is crucial for the reconstruction of paleo‐tsunamis. We report findings from viscous remanent magnetization studies of the boulders on Tongatapu Island, aiming to reconstruct their reworkings. Two boulders exhibited viscous remanence, whereas two larger boulders lacked viscous components but exhibited stable remanence. Both the viscous and stable components deviated from the geomagnetic field direction. These observations indicate that: (a) the boulders with a viscous component were reworked before the latest event, which could have reworked all boulders, and (b) the magnitude of the latest event was larger than that of an earlier event. The reworked timing indicated that the event occurred between 3,000 years ago and the fifteenth century. The difference in the wave height required to move boulders on the eastern and western coasts suggests that the source of the earlier tsunami was likely an eruption due to volcanoes along the Tonga Ridge.
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series Geophysical Research Letters
spelling doaj-art-9071be938ccf4dfc86b175c863ddfdd92025-08-20T03:02:07ZengWileyGeophysical Research Letters0094-82761944-80072024-11-015121n/an/a10.1029/2024GL110932Ancient Tsunami Records in the Viscous Remanent Magnetization of Reworked Boulders in the Kingdom of TongaTetsuro Sato0Norihiro Nakamura1Masahiko Sato2Chie Kato3Kazuhisa Goto4Masashi Watanabe5Kenji Satake6Taaniela Kula7Department of Earth Science School of Education Waseda University Tokyo JapanInstitute for Excellence in Higher Education Tohoku University Miyagi JapanDepartment of Earth and Planetary Science The University of Tokyo Tokyo JapanFaculty of Social and Cultural Studies Kyushu University Fukuoka JapanDepartment of Earth and Planetary Science The University of Tokyo Tokyo JapanEarth Observatory of Singapore Nanyang Technological University Jurong SingaporeEarthquake Research Institute The University of Tokyo Tokyo JapanTonga Geological Services Ministry of Lands and Natural Resources Nuku'alofa TongaAbstract The movement history of boulders is crucial for the reconstruction of paleo‐tsunamis. We report findings from viscous remanent magnetization studies of the boulders on Tongatapu Island, aiming to reconstruct their reworkings. Two boulders exhibited viscous remanence, whereas two larger boulders lacked viscous components but exhibited stable remanence. Both the viscous and stable components deviated from the geomagnetic field direction. These observations indicate that: (a) the boulders with a viscous component were reworked before the latest event, which could have reworked all boulders, and (b) the magnitude of the latest event was larger than that of an earlier event. The reworked timing indicated that the event occurred between 3,000 years ago and the fifteenth century. The difference in the wave height required to move boulders on the eastern and western coasts suggests that the source of the earlier tsunami was likely an eruption due to volcanoes along the Tonga Ridge.https://doi.org/10.1029/2024GL110932tsunami boulderviscous remanent magnetizationpaleotsunamireworking historytsunami magnitudetongatapu island
spellingShingle Tetsuro Sato
Norihiro Nakamura
Masahiko Sato
Chie Kato
Kazuhisa Goto
Masashi Watanabe
Kenji Satake
Taaniela Kula
Ancient Tsunami Records in the Viscous Remanent Magnetization of Reworked Boulders in the Kingdom of Tonga
Geophysical Research Letters
tsunami boulder
viscous remanent magnetization
paleotsunami
reworking history
tsunami magnitude
tongatapu island
title Ancient Tsunami Records in the Viscous Remanent Magnetization of Reworked Boulders in the Kingdom of Tonga
title_full Ancient Tsunami Records in the Viscous Remanent Magnetization of Reworked Boulders in the Kingdom of Tonga
title_fullStr Ancient Tsunami Records in the Viscous Remanent Magnetization of Reworked Boulders in the Kingdom of Tonga
title_full_unstemmed Ancient Tsunami Records in the Viscous Remanent Magnetization of Reworked Boulders in the Kingdom of Tonga
title_short Ancient Tsunami Records in the Viscous Remanent Magnetization of Reworked Boulders in the Kingdom of Tonga
title_sort ancient tsunami records in the viscous remanent magnetization of reworked boulders in the kingdom of tonga
topic tsunami boulder
viscous remanent magnetization
paleotsunami
reworking history
tsunami magnitude
tongatapu island
url https://doi.org/10.1029/2024GL110932
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