TsunamiTsunami

Series of very long-wavelength waves on the ocean

TsunamiTsunami

== "tidal wave" "tidal wave"

Tsunami has nothing to do Tsunami has nothing to do with tideswith tides

Video clip:Video clip:TsunamisTsunamis

Tsunami waves Tsunami waves

Very small out in the open oceanVery small out in the open ocean Amplitude of only ~ 1 meterAmplitude of only ~ 1 meter Very long wavelengths (up to 100 km)Very long wavelengths (up to 100 km) Travel very fast (as much as 500 mph)Travel very fast (as much as 500 mph)

Tsunami waves Tsunami waves

When waves reach shallow water, they When waves reach shallow water, they "feel" the shallow bottom, just like "feel" the shallow bottom, just like ordinary waves, and they slow down (to ordinary waves, and they slow down (to 20-30 mph)20-30 mph)

Because of the massive energy, this Because of the massive energy, this slowdown causes them to build up very slowdown causes them to build up very high (up to 50-100 m)high (up to 50-100 m)

Tsunami can be generated by Tsunami can be generated by any process that displaces a any process that displaces a large amount of water: large amount of water:

Sub-sea earthquakesSub-sea earthquakes Giant landslides Giant landslides Volcanic eruptionsVolcanic eruptions Meteorite impactsMeteorite impacts

Runup Runup Maximum height above sea level Maximum height above sea level

reached by a tsunami when it reached by a tsunami when it reaches shorereaches shore

Inundation Inundation Horizontal distance from the normal Horizontal distance from the normal

water's edge reached by a tsunamiwater's edge reached by a tsunami

Hilo after 1946 tsunami

1952 Tsunamiwave passingunder bridgeat Haleiwa

Kaiaka Bay

1946 tsunami -- Hilo harbor: 159 fatalities

Beach in Laie, O`ahu before tsunamigenerated by 1957 quake in Aleutians

1983 Japan tsunami -- water recedes

1983 tsunami in Japan104 people drowned700 boats, 59 houses

destroyed$800 Million property

damage

2000

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Bay, Koko Crater, Castle JunctionBay, Koko Crater, Castle Junction Bring water, hat, sun screen, walking Bring water, hat, sun screen, walking

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