A model for wave abrasion on underwater bedrock, with an application to rapidly downwearing tephra cones adjacent to Surtsey Island in Iceland

Wave abrasion, a key process shaping shallow-water coastal bedrock, has been quantified through a predictive model linking erosion rates to wave-induced shear stress and bedrock resistivity. Applied to two tephra cones near Surtsey Island in Iceland—Jólnir (storm-exposed) and Syrtlingur (sheltered)—the model reveals distinct abrasion dynamics: Syrtlingur experiences 33% less deep-water wave energy but fourfold more efficient abrasion, with a shallower wave base (34.4 m vs. 51.5 m for Jólnir). The findings highlight how storm exposure and sheltering influence erosion patterns, offering insights into coastal bedrock evolution under varying hydrodynamic conditions.

Sunamura, T. (2021). A model for wave abrasion on underwater bedrock, with an application to rapidly downwearing tephra cones adjacent to Surtsey Island in Iceland. Earth Surface Processes and Landforms, 46(8), 1600–1609. Portico. https://doi.org/10.1002/esp.5128