Extreme low-frequency waves on the Ofu, American Samoa, reef flat

Coral Reefs
By: , and 



The southern fringing reef along Ofu, American Samoa, has been a focus of coral research owing to the presence of super-heated pools on the reef flat, where corals thrive in elevated sea temperatures. Here, we present the first documentation of exceptionally large low-frequency (periods > 100 s) waves over this reef flat. During a large, southerly swell event, low-frequency waves on the inner reef flat had mean heights of 0.7 m and periods of 2–4 min and are estimated to have contributed up to 50% of the total water levels. One observed low-frequency wave had a trough-to-peak vertical height of 1.5 m, possibly representing the largest low-frequency wave ever directly observed on a reef flat. These large, low-frequency waves, which were likely amplified by reef resonance, are important factors in coastal hazards such as flooding and erosion and may also be relevant to coral health and resilience.

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Publication type Article
Publication Subtype Journal Article
Title Extreme low-frequency waves on the Ofu, American Samoa, reef flat
Series title Coral Reefs
DOI 10.1007/s00338-023-02453-w
Volume 43
Year Published 2024
Language English
Publisher Springer
Contributing office(s) Pacific Coastal and Marine Science Center
Description 7 p.
First page 185
Last page 191
Country United States
Other Geospatial Ofu, American Samoa
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