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Copyright 2002, all rights reserved
WONDER QUEST with April Holladay, A Weekly Column * May 1, 2002* Albuquerque
Tsunami! In a river?
Q: Can a local tsunami occur in rivers or in small lakes (like the Dead Sea or Lake Tiberias)? --Eran Gafni
A: Yes it can. As you know, tsunamis are waves that sweep across vast stretches of ocean to flood the land- usually after an earthquake
drops or lifts the ocean floor. However, the same phenomenon can happen in rivers and lakes. Moreover, an ocean-going tsunami can roll
up into a river and cause a local tsunami there.
[Austin Post, USGS] Mt. St. Helens erupting, May 1980
That's what happened in 1946 on the Big Island of Hawaii. A tsunami advanced up the Wialuku River near the
city of Hilo. On April 1, a 7.4 magnitude earthquake shook the Aleutians and started a tsunami rolling
thousands of miles down the Pacific Ocean to Hawaii. The powerful wave engulfed the Hawaiian Islands and
lifted a 5-story-high wall of water (56 feet or 17 meters) into Hilo Bay in the Big Island of Hawaii. In addition
to killing 159 people and causing millions of dollars of damage, the tsunami surged up the Wialuku River near
Hilo. It tore a whole span off the railroad bridge.
Tsunamis can occur in lakes, too. On May18, 1980 in Washington State, the top of the volcano, Mount St.
Helens, blew off. The rubble that was a mountaintop slid downhill at great speed and slammed into Spirit Lake:
causing a local tsunami of formidable size. The giant wave surged around the lake as high as 820 feet (250
meters) above the old lake level-almost as high as the Eiffel Tower. The high water ran up the valley head, then
swept back into the lake, rinsing the valley sides clean of timber and sediment.
Tsunamis may have occurred in the Dead Sea in 315 A.D. and again in 362 A.D. but none in recent times.
(Answered by April Holladay, science correspondent, May1, 2002)
Further Surfing:
How a tsunami
forms, and why the water goes out sometimes
The
highest tsunami, Alaska, 1958
Tsunamis: lake
water sloshing like bathtub water
USATODAY.com: tsunami graphic
USC, tsunami research group: tsunami in Wialuku River
USGS: Mount St. Helens, Washington
NOAA/NGDC: Tsunami events database (worldwide)
Federal Emergency Management Agency: Tsunami safety
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