Aleutian islands tsunami 1946
Wreckage of political party clubhouse, Kamehameha Avenue, Hilo, Hawaii
Background
On April Fools Day 1946, an earthquake near the Aleutian Islands sent out large waves of water. At the time there was no warning system to detect when the tsunami waves would reach the land. It was so unexpected that a lighthouse that was around five stories tall, constructed from concrete and steel, was blindsided by a one hundred foot wave and completely obliterated. There were five men operating the lighthouse at the time, unfortunately all of them were killed.
Around five hours later, the tsunami made its way to Hilo, Hawaii. The waves were measured to be around twenty-four feet in height. Hilo was hit mare than six times with wave after wave. By the time it was over, buildings where torn from their foundations, trees littered the streets, and one hundred and fifty-nine lives were claimed.
The Scotch Cap Lighthouse in Unimak Island, Alaska
The remains of Scotch Cap Lighthouse and surrounding cliff area after the tsunami hit
What was Lost
Deaths: 164
Damage: $26,000,000
A wave propagating past an automobile bridge up the Wailuku, Hilo Bay, Hawaii
Tsunami sweeps across Cocoanut Island, Hilo Bay, Hawaii
What was learned
- "Damage from tsunamis come in three ways: (1) damage from the impact for the tidal waves, (2) damage caused by the debris picked up and swept along the wave, and (3) the scouring action caused by the retreating wave."
- Building elevation does play an important role in the chances of survival against a tsunami. The farther away a building is from the coastline the higher the chance that the waves will not reach it. Constructing a building on stilts or piers to allow water to pass underneath is also a solution.
- The orientation of the building also matters, walls that are built with the flow of the water fared much better.
- Building materials also play a significant role, reinforced concrete has a better chance of survival that any other material.
- Mitigating the amount of debris can save lives, victims of the tsunami were most commonly killed by large potions of construction material that had become dislodge and thrown about by the waves.
- Seawalls can reduce the force of the wave, while water may be able to get over the walls it is still a great defense against the amount of pressure being thrown forward.
A bore advances past the railroad bridge at the mouth of the Wailuku River, Hilo Bay, Hawaii
A view of the tsunami generated in the Aleutian Islands striking the beachfront area at the Puumaile Tuberculosis Hospital on the island of Hawaii
Significance
-Studies about the nature of tsunamis have continued to evoke further ideas about construction, material, and structural combinations that can adequately perform against the pressure of the waves.
-This tsunami led to the creation of the nation's first Seismic Sea Wave Warning System (SSWWS).
- The west coast of the United States had adopted its own series of early warning systems.
Tsunami breaking over Pier No. 1 in Hilo Harbor, Hawaii. The man indicated by the arrow did not survive.