Updated: Sep 19, 2019
Tsunamis have been cursing our worlds waters for the past 8,000 years but no one ever worried that one of these alarming waves would reach the small town of Port Alberni. Tsunamis can threaten us, our homes, and our community, and we must always be prepared for what may happen.
A tsunami is a Japanese word for harbor wave or tidal wave. 80% of tsunamis happen within the "ring of fire" which is a major area in the basin of the Pacific Ocean where many earthquakes and volcano eruptions occur. Tsunamis do not resemble normal undersea currents, rather they are a series of large waves that send an extensive amount of water onto our land. These eerie waves are caused by large undersea earthquakes at tectonic plate boundaries. When the ocean floor at a plate boundary raises or falls abruptly it displaces the water above and sends rolling waves towards the land that will eventually become tsunamis. Tsunamis can also be caused by underwater landslides or volcanic eruptions. The waves may appear small at first but as they approach shoreline and enter shallow water they grow in energy and in height, they can travel as fast as 500 miles per hour without losing a ton energy. The reason tsunamis are able to travel this way is because of their long wavelengths.
When a tsunami hits land it produces a vacuum effect that sucks coastal water seaward that leaves harbors and seafloor exposed. A tsunami is composed of a series of waves called a wave train; so when people are experiencing a tsunami and expect only one wave they are very mistaken and should always expect more to come. Their best defense against tsunamis is an early warning and to seek higher ground.
On March 27th, 1964 the afternoon of Good Friday, the strongest earthquake recorded in North America hit Anchorage, Alaska and became known as the great Alaskan earthquake/the Good Friday earthquake. The 9.2 magnitude earthquake had a depth of 25 kilometers, lasted 4 minutes and 38 seconds and killed nearly 131 people. Many houses, buildings and infrastructures were damaged or destroyed.
This earthquake was caused by a massive underwater slide at Port Valdez in Prince William Sound and created an 8.2-meter tsunami that destroyed the village of Chenga killing 23 of the 68 people who lived there.
Post-quake tsunamis severely affected Whittier, Seward, Kodiak, Oregon, California and British Columbia. The Alaskan earthquake caused two types of tsunamis: one being a tectonic tsunami caused by tectonic plates moving and the second being a sub-aerial landslide tsunami caused by underwater landslides. Three hours after the earthquake a 1.4-meter tsunami reached Prince Rupert BC but did little damage.
Around midnight the first two waves started traveling up the 40 kilometer Alberni inlet to Alberni and Port Alberni. No one expected the tsunami to hit as hard as it did because we are in the middle of an island; but it's because of our inlet that the tsunami did hit so hard. The narrow inlet amplified the size and intensity of the wave because as the inlet got smaller, the wave grew taller and faster. The first wave that hit Alberni and Port Alberni was 2.44 meters and one hour later the second wave hit with a height of 3.05 meters. The second tsunami wave caused a significant amount of damage. However, instead of destroying houses it just picked them up and moved them to a different location. This is because of how the foundations of the houses where built at the time. The first two waves were followed by four more waves ranging from a height of 1.52 to 1.83 meters occurring at 90-minute intervals. These series of waves washed away 65 homes and damaged 375 others and It caused five million dollars in damage in both cities.
The aftermath of the tsunami resulted in the communities coming together to rebuild and the amalgamation of Alberni and Port Alberni in 1966. Although we may not be able to directly prevent tsunamis we can defiantly be prepared for them and not waiting for if another one is going to occur but being prepared for when it comes.
Written by J. Tardif
WATCH: Rememberig the 1964 Port Alberni tsunami
1964 Alaskan Tsunami
Case Study 2: 1964 Port Alberni Tsunami
This week in history
The Great Tsunami of 1965-virtual museum
The great M9.2 Alaska earthquake and tsunami of march 27, 1964