Large tsunamis reset growth of massive corals
Large tsunamis reset growth of massive corals
Corals at Ishigaki Island, Japan, are characterized by their high species diversity. Not only are they struck by storm waves generated annually by typhoons, the corals, especially the massive ones, in the fringing reef were buffeted by huge tsunami waves with a run-up height of ca. 30 m in 1771 Meiwa tsunami and its predecessors at few hundred-year intervals. We present field survey and numerical results demonstrating that such near-field large tsunamis could have reset the growth of massive corals, a phenomenon which large typhoons have not caused. Our field survey revealed that the massive corals in the lagoon are not attached to the bedrock but are instead located on the sandy sea bottom. Therefore, those are movable of sufficiently large wave inundated in the lagoon. Our numerical results further showed that the maximum velocity of the tsunami at the reef edge, calculable as < 21.2 m/s at the study area, is still high in the shallow lagoon, perhaps generating sufficiently strong hydrodynamic force to devastate the massive corals in the shallow lagoon entirely, as well as some presumed damages on tabular and branching corals on the reef crest and reef slope. This numerical result is consistent with the observed fact that even a 9-m long Porites boulder (about 220 t) was cast ashore by the 1771 tsunami. The sizes of the presently living massive corals of Porites spp. are consistent with our hypothesis that they started to grow after the latest 1771 tsunami event. At the coral reefs of high tsunami-risk countries, severe destruction of corals by large tsunami waves should be considered for their growth history because, depending on the bathymetry, coral characteristics, and tsunami hydrodynamic features, tsunamis can radically alter coral habitats. [Figure not available: see fulltext.].
Boulder, Coral, Coral boulder, Disaster, Hazard, Ishigaki Island, Numerical modeling, Tsunami, Tsunami effects on coral
Goto, Kazuhisa
83ebddaf-a094-4138-b5d0-47d561e975e3
Hongo, Chuki
f6320ec0-f4b4-4174-986c-dab215635bc8
Watanabe, Masashi
880b3e5b-42a4-49a2-b196-0d06e54e45db
Miyazawa, Keitaro
31b518d1-1afd-4e9f-b1ef-664a5a401145
Hisamatsu, Akifumi
8ce43b96-fe79-47ce-9487-09458834923c
13 February 2019
Goto, Kazuhisa
83ebddaf-a094-4138-b5d0-47d561e975e3
Hongo, Chuki
f6320ec0-f4b4-4174-986c-dab215635bc8
Watanabe, Masashi
880b3e5b-42a4-49a2-b196-0d06e54e45db
Miyazawa, Keitaro
31b518d1-1afd-4e9f-b1ef-664a5a401145
Hisamatsu, Akifumi
8ce43b96-fe79-47ce-9487-09458834923c
Goto, Kazuhisa, Hongo, Chuki, Watanabe, Masashi, Miyazawa, Keitaro and Hisamatsu, Akifumi
(2019)
Large tsunamis reset growth of massive corals.
Progress in Earth and Planetary Science, 6 (1).
(doi:10.1186/s40645-019-0265-2).
Abstract
Corals at Ishigaki Island, Japan, are characterized by their high species diversity. Not only are they struck by storm waves generated annually by typhoons, the corals, especially the massive ones, in the fringing reef were buffeted by huge tsunami waves with a run-up height of ca. 30 m in 1771 Meiwa tsunami and its predecessors at few hundred-year intervals. We present field survey and numerical results demonstrating that such near-field large tsunamis could have reset the growth of massive corals, a phenomenon which large typhoons have not caused. Our field survey revealed that the massive corals in the lagoon are not attached to the bedrock but are instead located on the sandy sea bottom. Therefore, those are movable of sufficiently large wave inundated in the lagoon. Our numerical results further showed that the maximum velocity of the tsunami at the reef edge, calculable as < 21.2 m/s at the study area, is still high in the shallow lagoon, perhaps generating sufficiently strong hydrodynamic force to devastate the massive corals in the shallow lagoon entirely, as well as some presumed damages on tabular and branching corals on the reef crest and reef slope. This numerical result is consistent with the observed fact that even a 9-m long Porites boulder (about 220 t) was cast ashore by the 1771 tsunami. The sizes of the presently living massive corals of Porites spp. are consistent with our hypothesis that they started to grow after the latest 1771 tsunami event. At the coral reefs of high tsunami-risk countries, severe destruction of corals by large tsunami waves should be considered for their growth history because, depending on the bathymetry, coral characteristics, and tsunami hydrodynamic features, tsunamis can radically alter coral habitats. [Figure not available: see fulltext.].
Text
s40645-019-0265-2
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Accepted/In Press date: 21 January 2019
Published date: 13 February 2019
Keywords:
Boulder, Coral, Coral boulder, Disaster, Hazard, Ishigaki Island, Numerical modeling, Tsunami, Tsunami effects on coral
Identifiers
Local EPrints ID: 494518
URI: http://eprints.soton.ac.uk/id/eprint/494518
ISSN: 2197-4284
PURE UUID: 4ba5d4d3-175d-4538-a6c6-06220de79b4c
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Date deposited: 10 Oct 2024 16:31
Last modified: 21 Aug 2025 02:52
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Author:
Kazuhisa Goto
Author:
Chuki Hongo
Author:
Masashi Watanabe
Author:
Keitaro Miyazawa
Author:
Akifumi Hisamatsu
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