Tsunami trimlines identified across different islands of the Tonga archipelago (NERC Grant NE/X002454/1)

Tsunami trimlines identified across different islands of the Tonga archipelago. Trimlines have been used as a reference land feature following the January 2022 Tonga tsunami event that ripped off vegetation and built-up areas. Trimlines are distinctive limits between an area with sand coverage, vegetation destruction, and soil erosion on the one hand, and the unaffected natural vegetation on the other. This distinction provides a good landmark to map the inundation width and the landward extension of tsunami runup. In this case, the trimlines have been manually delineated by BGS - Earth Observation team using different high-resolution satellite datasets both optical (KompSat, Planet, Pleiades, WorldView) and radar (TerraSAR-X). Trimlines are well known from task-force publications documenting recent tsunami detection efforts and provide key information to support tsunami triggering mechanism models. For more info, see https://www.usgs.gov/media/images/tsunami-terms and Scheffers et al. (2012), https://doi.org/10.1007/s11069-010-9691-6