Drop in sea level prior to tsunami flooding. The shoreline moves seaward, sometimes by a kilometre or more, exposing the sea bottom, rocks, and fish. The recession of the sea is a natural warning sign that a tsunami is approaching.

A tsunami capable of destruction in a particular geographic region, generally within about 1,000 km of its source. Regional tsunamis also occasionally have very limited and localized effects outside the region. Most of the destructive tsunamis can be classified as local or regional, meaning their destructive effects are confined to coasts within a hundred km, or up to a thousand km, respectively, of the source -- usually an earthquake. It follows that many tsunami related casualties and considerable property damage also comes from such tsunami.

The upward change or elevation in sea level associated with a tsunami, a tropical cyclone, storm surge, the tide, or other long term climatic effect.

1) Difference between the elevation of maximum tsunami penetration (inundation line) and the sea-level at the time of the tsunami. 2) Elevation reached by seawater measured relative to some stated datum such as mean sea level, mean low water, sea level at the time of the tsunami arrival, etc., and measured ideally at a point that is a local maximum of the horizontal inundation.

Set of tsunami run-up values measured or observed along a coastline.