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

January 22, 2024

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.

Publication Year 2024
Title Extreme low-frequency waves on the Ofu, American Samoa, reef flat
DOI 10.1007/s00338-023-02453-w
Authors Olivia Cheriton, Curt Storlazzi, Ferdinand Oberle, Kurt J. Rosenberger, Eric K. Brown
Publication Type Article
Publication Subtype Journal Article
Series Title Coral Reefs
Index ID 70251134
Record Source USGS Publications Warehouse
USGS Organization Pacific Coastal and Marine Science Center