Tsunami/Phase 1/Lesson1 5

Tsunami -- Phase 1: Defining tsunami Contents Introduction  |  Teaching Guide  |  Phase 1: Defining tsunami  | Phase 2: The waves have gone... What now?  |  Phase 3: Tsunami survivor Phase 1 Lesson 1 Defining tsunami  | What is a tsunami?  |  Waves  |  Wave energy  |  Tsunami height  |  Height & run-up  |  Simulation Lesson 2 Warning sign  |  Natural signs  |  Official warnings  |  Unofficial warnings Lesson 3 Tsunami Signs  |  Signs quiz  |  Phase 1 summary
Height and Run Up
Tsunami waves are described by both their height and their “run-up”. Tsunami run-up is the maximum height that the tsunami reaches on land above normal sea level at the time (see diagram). For example, if there is a house across the street from the beach that sits 5 metres above the sea level at high tide: a tsunami, occurring at high tide, would have 5 metres run-up if the water reached the doorstep of that house. Run-up is dependent on the type and size of tsunami, as well as coastal landscape and how the land is being used. Run-up is a more useful measure than tsunami height as it relates more closely to the onshore effects of a tsunami. Run-up is the most visibly destructive part of the tsunami as the water picks up debris along its way and with great force swamps the coastal landscape: causing damage to anything in its path (buildings, etc).
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