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- Lituya Bay
- Episode 5
Lituya Bay: One Wave. 1,720 Feet. Survivors.Episode 51:46
The Three Waves That Kept Growing
The 1936 eyewitness accounts expose a recurring threat whose exact trigger investigators cannot prove.
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Transcript
Water surged 1,740 feet up the opposite wall of Gilbert Inlet.
Lituya Bay: ice-scoured, 720-foot-deep inlet behind a 33-foot entrance sill.
Eyewitnesses described the 1936 event as three waves growing higher.
Inner walls rise steeply from 2,200 to more than 6,000 feet.
At least four giant waves rushed from the bay's head in little more than a century.
Those 1936 waves traveled about 22 miles per hour and grew taller.
Investigators considered a moving glacier front or submarine sliding likeliest.
No evidence showed if ice or an underwater slide moved enough material.
The record showed a pattern, not an answer: repeatable destruction without a proven trigger.
Miller tied frequent giant waves to steep, recently glaciated slopes, fractured rock, rain.
On July 9th, 1958, a 7.8-magnitude quake ruptured 125 miles of fault.
About 40 million cubic yards of rock plunged into Gilbert Inlet.
Howard Ulrich heard a roar after about a minute of shaking.
The gravity wave raced toward the mouth at 97 to 130 mph.
The outer bay's three fishing boats faced the wave; two were sunk.
The wave stripped forests to a trimline reaching 1,720 feet above the bay.
Later modeling showed a giant air cavity could displace more water than rock alone.
Where it leaves off
But if Lituya Bay could make giant waves in several ways, scientists still had to prove how the 1958 landslide produced a splash more than 500 meters high…
Sources
- ALASKA STATE LIBRARYdggs.alaska.govprimary
- 60 years ago: The 1958 earthquake and Lituya Bay megatsunami | Alaska Earthquake Centerearthquake.alaska.edusecondary
- LANDSLIDE TSUNAMISnctr.pmel.noaa.govsecondary
- Interagency Technical Operations Plan fordggs.alaska.govsecondary
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