Last week’s magnitude 7.0 earthquake in Haiti was the strongest the country has seen in more than 2 centuries. With that in mind, what are the odds of a similar earthquake happening in the United States?

Chance of a Magnitude 7.0 Earthquake:

Los Angeles: 1 in every 200 years

Anchorage: 1 in every 400 years

Las Vegas: 1 in every 50,000 years

Green Bay: 1 in every 20 million years.

The last earthquake to impact the United States with a magnitude of at least 7.0 was in 2005, when a magnitude 7.2 earthquake occurred off the coast on northern California. Fortunately, since the earthquake was off the coast only minor damage was reported.

But what exactly does a magnitude 7.0 earthquake mean? The Richter scale is shown below with corresponding severity.

Magnitude 3.5 or less: Generally not felt, but recorded

Magnitude 3.5 – 5.4: Often felt, but rarely causes damage.

Magnitude 5.5 – 5.9: At most slight damage to well-designed buildings. Can cause major damage to poorly constructed buildings.

Magnitude 6.1 – 6.9: Can be destructive in areas up to 100 km across where people live.

Magnitude 7.0-7.9: Major Earthquake. Can cause serious damage over larger areas.

Magnitude 8 or greater: Can cause serious damage in areas several hundred kilometers across.

The graphic below displays the faults and fault areas across the continental US. As you can see, the majority of the faults are in the western portions of the nation with several fault areas in the central and eastern US.

Faults and Fault Areas

However, just because there are fault areas in the east, doesn’t mean that these areas are more prone to seeing earthquakes. In fact, from 1974 to 2003, there were only 17 earthquakes in Illinois that had a magnitude of 3.5 or greater.

Number of Earthquakes per State 1974-2003

Here is how the list breaks down for states with the most earthquakes:

States with the most Earthquakes

Alaska tops the list by far. They see more than 50% of the nations earthquakes. The strongest earthquake ever in the US occurred just east of Anchorage, Alaska in 1964. The quake measured a 9.2 on the Richter scale. Below are damage photos from the event.

Elementary school destroyed in Anchorage

Damage from Tsunami caused by quake

The earthquake claimed the lives of 131 people and caused an estimated 2.7 billion dollars worth of damage (adjusted for inflation)

Until Next Time,

Meteorologist Andrew Thut