For residents of San Francisco and Los Angeles, being aware of the potential for an earthquake is just part of the daily routine. People who live in the rest of the United States would be remiss to think that they are completely safe from earthquake danger just because they don’t live in these major earthquake hotbeds.
The fact of the matter is, 42 of the 50 states have been declared as at-risk zones for earthquakes, with some of those states being at significant risk. Some of these earthquake danger zones are places one would never expect – a fact that makes their potential even more dangerous than those aforementioned Californian cities. Here’s a rundown of earthquake-vulnerable cities that may surprise you:
1. Little Rock, Arkansas – Running through northeast Arkansas is a fault line that caused the most powerful earthquakes to ever hit the eastern United States. In 1811 and 1812, the New Madrid Fault caused a series of earthquakes that reached 8.0 in magnitude. According to some estimates, the effects were felt over 50,000 square miles. The rumbling caused church bells in Boston to ring and even caused the Mississippi River to flow backwards temporarily. Unfortunately, the New Madrid Fault isn’t the only fault Little Rock citizens have to worry about. In 2009, the University of Arkansas announced the discovery of a previously unknown fault in eastern Arkansas that is separate from the New Madrid Fault.
2. Las Vegas, Nevada – Sin City is not a spot most people would associate with earthquakes, but the existence of 1,500 faults that crisscross Nevada make the state the third most seismically active region in the U.S. In fact, in 1954 Nevada was hit by a 7.0 magnitude earthquake. Fortunately, the population was sparse and damage was minimal, but it could be an entirely different story if an earthquake were to occur today in Vegas. To date, geologists have identified seven major fault lines in the Las Vegas valley. What’s the chance that Las Vegas would be hit by a 5.0 or greater earthquake in the next 25 years? Researchers put the probability at 50 percent.
3. Portland, Oregon – Oregon is a hotbed of faults and seismic activity, and the city of Portland is particularly vulnerable. Recently, geologists have identified three shallow faults underneath the most populated sections of Portland. More worrisome is the Cascadia Subduction Zone, which is a 680 mile long fault off the coast of Oregon. Along this fault line, one tectonic plate overlaps another. Eventually, a catastrophic “megathrust” earthquake will occur. In fact, researchers at Oregon State University estimate that there is up to a 40% chance that an earthquake of magnitude 8.0 or higher will occur off the coast of Oregon in the next half century.
4. Salt Lake City, Utah – The impressive scenery that makes up the Utah landscape is also evidence of the area’s potential for potentially dangerous earthquakes. Utah’s largest fault, the Wasatch Fault, runs east of Salt Lake City and is capable of causing an earthquake of 7.0 or more in magnitude. Add in geological factors such as the soft ground that Salt Lake City sits on and the risk is further amplified. Scientists estimate the Wasatch Front has a 1-in-7 chance of witnessing a magnitude 7.0 earthquake.
5. Dallas/Fort Worth, Texas – With its location on the Great Plains – far away from common hotspots for seismic activity – this part of North Texas would seem relatively safe from earthquakes. However, a marked increase in earthquake activity over the past few years has shown that may not be the case. The unusual increase in earthquakes has been linked to fracking according to some experts. In 2012, a seismologist at the University of Texas found a correlation between injection wells and small earthquakes. While most earthquakes top out around 3.0, they were nearly unheard of in the Dallas-Fort Worth area before fracking started.
6. Memphis, Tennessee – Memphis is another city at risk due to the New Madrid fault. The New Madrid seismic zone records about 150 to 200 earthquakes annually, though the vast majority or tremors are too weak to be felt. Still, the seismic activity suggests the fault is a very real threat to the city of Memphis. Were an earthquake of moderate to severe magnitude to occur in Memphis, the aging and non-reinforced buildings that make up the city could lead to potential disaster. The most recent major earthquake that affected Memphis was a 5.0 that occurred in 1865. According to eyewitnesses, the earth undulated and waves formed in the river.
7. Washington, D.C. – Until a few years ago, nobody would have associated the nation’s capital with high earthquake risk. That all changed with the 2011 earthquakes that struck the Virginia Seismic Zone and shook the ground in D.C., reminding the public that the East Coast is not immune to earthquakes. In addition to the high population, an earthquake in this region poses a special risk due to the widespread nature of the 2011 quake, which triggered landslides over a wider area than any other recorded quake in the world that year. The reason earthquakes in this area can be felt over such a wide area is the denser and more solid nature of the continental crust, whereas the crust on the West Coast is more broken up, confining tremors to a smaller area.
8. Boise, Idaho – Numerous small to moderate earthquakes hit Idaho on a regular basis, making the state the fifth most active state in terms of seismic activity. Significant quakes have struck the state in the past. In fact, Idaho’s most powerful earthquake ever recorded occurred relatively recently (geologically speaking). In 1983, the Borah Peak quake had a magnitude of 6.9. While Boise is not usually at the center of these quakes, the potential for an earthquake exists. One of a significant magnitude could be especially dangerous as Boise lies at the foot of three dams which, if damaged by earthquake activity, could lead to disastrous flooding.
9. Portland, Maine – The largest city in Maine with a population of around 66,000, Portland isn’t well-known for its earthquake risk. But perhaps it should be. The area does have many faults, and in fact earthquakes in New England are quite common, albeit not very strong. That doesn’t mean, however, that a large earthquake won’t strike in this region. In October of 2012 a 4.0 temblor shook buildings and knocked things off shelves; there’s no reason to believe a stronger quake isn’t possible. And earthquakes in this area are generally felt over a wide area, similar to the 2011 Virginia quake, because of the old and dense crust.
Looking to escape earthquakes completely? Your options are rather limited in America. North Dakota, Wisconsin, Minnesota, and Florida are at little risk for this kind of serious seismic event. Otherwise, stay prepared and don’t ignore seismic activity in your region.