5 of the Worst Earthquakes in US History

Earthquakes are devastating, but which are the worst ones?

Earthquakes have been happening since the dawn of the planet earth. Even before the atmosphere cooled and life began its trepidatious advance from amino acids to single-celled organisms, earthquakes and tectonic motion shaped and changed the planet.

How Are Earthquakes Measured?

Modern measurements of earthquakes started in 1935 when Charles Richter created the Richter scale. He proposed measuring earthquakes using an exponential measuring system. 

Speaking simply, the Richter scale measures the size of the seismic waves produced by an earthquake to get the 1-10 measurement we are used to.

Most natural disasters are measured by their power output on a linear scale. Hurricanes and tornadoes are measured by wind speed; tsunami’s are typically measured by the height of their waves. Earthquakes are measured by their energy output on an exponential scale. 

This means that each progression in magnitude represents ten times more power than the previous magnitude. High-magnitude earthquakes are rare, but when they happen, they are devastating. 

The 5 largest earthquakes in US History

The most powerful earthquakes in US history may surprise people. The United States Geological Survey’s archives put all of the most powerful earthquakes experienced in the United States up in Alaska. 

Here are the top 5 most powerful earthquakes ever to happen on US territory. 

1. 1906 Aleutian Islands Earthquake – 8.3

This earthquake is an easy one to forget. In spite of the massive amounts of energy released, no damage has been attributed to this earthquake. 

This shake occurred within 30 minutes of an earthquake in Chile with a magnitude of 8.2. Of these two earthquakes, only the Chilean one is said to have caused a tsunami. 

Due to its low impact on everyday life, this earthquake, although powerful, has slipped into the forgotten archives of US earthquakes.

2. 1957 Andrenof Island earthquake – 8.6

In 1946, an earthquake occurred off the shores of Alaska. The earthquake caused a tsunami that indirectly resulted in 2 deaths and close to $50 million worth of damage. 

Like the 1906 earthquake off the coast of the Aleutian Islands, the 1957 Alaska earthquake received little acclaim in spite of the power it released. 

3. 1946 Aleutian Islands earthquake – 8.6

Unlike the 1957 Earthquake, the 1946 Aleutian Island earthquake caused a significant amount of damage for its time. 

The tsunami that resulted from the earthquake is estimated to have reached up to 138 ft high when it hit an island closest to the epicenter. 

The unexpected wave wreaked havoc in the Hawaiian islands, destroying hundreds of buildings and over 150 casualties. The financial cost of the earthquake would reach over $300 Million in today’s dollars. 

The catastrophic results of this earthquake helped prompt the foundation of the Pacific Tsunami Warning Center, one of the institutions created to detect early signs of tsunamis.

4. 1965 Rat Islands earthquake – 8.7

The 1965 earthquake is yet another earthquake off the remote island chain known as the Aleutian Islands.

This earthquake released the approximate equivalent of 169 Megatons of TNT of energy. That is to say, this earthquake was over 10,000 times more powerful than the bomb that destroyed Hiroshima. 

Its remote location meant there was very little in the terms of monetary damage and loss of life. In fact, there were no fatalities and only minor structural damages suffered by buildings and military infrastructure on other islands in the Aleutian chain. 

5.1964 Prince William Sound Earthquake – 9.2

This earthquake in 1964 was the second largest earthquake ever recorded. 

The energy released in the explosion was about 12,000 times more powerful than the bomb that destroyed Hiroshima. The shockwaves triggered tsunamis and landslides that devastated the local region and caused additional fatalities worldwide. 

This earthquake caused hundreds of millions of dollars of damage, turning the harbors and coastal regions into a melting pot of civilized destruction. 

Why does Alaska have so many earthquakes?

It may be surprising to many that the most powerful earthquakes in the United States happen in Alaska. In fact, Alaska has the most earthquakes of all the United States.

Most of the infamous earthquakes in the United States happen in California; it would make for most people to think earthquakes are more frequent in California. 

The reason we hear more about California earthquakes is because California has a denser population than other locations along active fault lines. More people means more damage to infrastructure, more damage means more news.

Alaska has so many earthquakes because it has a larger coast along a more active fault. California has roughly 840 miles of coastline along the ring of fire, the most volcanically and tectonically active region in the world. 

Alaska has over 2,000 miles of territory along the ring of fire. In fact, the Aleutian Islands, the chain of islands extending west towards Russia, were created by the convergence of the pacific and North American plates.

Does California have more earthquakes than any other state?

Of all the states, California is the second most tectonically active. The state with the most earthquakes is Alaska. The Alaskan region has had thousands more earthquakes in the last 25 years than California or any other state.

It’s a simple evaluation of numbers. Alaska has more territory bordering a tectonically active region than California by a large margin. 

This, combined with the fact that the Alaskan fault line is the convergence point (the area where two plates meet and) between two major tectonic plates, it only makes sense that it would be the center of powerful earthquakes.

Does Your Insurance Cover Earthquake Damage? Hudson Douglas Public Adjusters Can Help!

Your insurance policy may not state you are protected from the worst earthquakes, but is that true?

Insurance is a complicated web that can be used in unexpected ways. We here at Hudson Douglas Public Adjusters can help you determine if there is any way to get your insurance to cover damage from whatever disaster you are facing.
Call us today! It may surprise you what we find.