Infragravity wave

Infragravity waves are a type of low-frequency wave typically found in ocean environments. They have periods that range from approximately 30 seconds to several minutes, which makes them significantly longer than regular wind-driven surface waves, which often have periods of a few seconds to around 10 seconds. Infragravity waves are generated by the interaction of regular ocean waves with the shoreline and the seafloor. When wind-generated waves break, they can create these longer-period waves through non-linear interactions.