Which statement best defines a seiche?

• A. Waves spread behind obstacles
• B. Often used incorrectly for rip current
• C. Oscillation of water in enclosed basin
• D. Underwater earthquake, landslide, eruption

Answer: (C)

A seiche is the oscillation of water inside an enclosed or semi-enclosed basin, like a harbor, cove, or lake, set in motion by a disturbance such as wind or a seismic event. The basin acts like a container that lets the water slosh back and forth, so water levels rise on one side and then swing to the other, often continuing for minutes to hours as the oscillation decays. This differs from waves that simply radiate across the surface, or from tsunamis caused by underwater earthquakes or landslides, which travel long distances across the ocean. The defining idea is the standing-water motion within a bounded space.