Seiche

A seiche is a standing wave that oscillates in an enclosed or partly enclosed basin, harbor, lake, or bay, after a disturbance such as wind, a pressure change, or a passing tsunami sets the water sloshing at the basin’s natural period. The period depends on basin length and depth (the Merian formula). Harbor seiches can surge moored vessels and snap mooring lines even in calm offshore conditions; they overlap with meteotsunami forcing.