The Risks on the Wasatch Front

April 18, 2019 0 Comments

When it comes to talking about areas at risk for earthquakes, we tend to discuss the usual suspect--California. This is for good reason--scientists report that there is a 99.7% chance that a magnitude 6.7 quake or larger will strike in the next 30 years in the Golden State.

But, unfortunately, California and a few other more obvious states such as Hawaii, Washington, and Alaska aren’t the only states at risk. There are other parts of the United States that need to remain aware of earthquake dangers--even if they aren’t located along the infamous Ring of Fire. Those in the Midwest along the New Madrid fault are some. Utah is another.

You may have heard about the recent series of quakes in populous areas of Utah. The state gets about 700 earthquakes per year, although only 2% of them are strong enough to be felt. However, if you look to the past, a “big one” has hit a vulnerable area, known as the Wasatch Front, every 350 years...and it’s been about that long since the last one hit.

Even if you don’t live in Utah, it’s important to understand the reality of the situation. You may find yourself or a loved one visiting the area, and understanding both the dangers and how to prepare can make the difference between life and death.

Read on to learn more about the likelihood of a deadly earthquake in Utah--and learn tips for how to prepare along the way.

Utah and the Wasatch Fault

Located on the western edge of the Wasatch mountains in Utah, the Wasatch Fault is an active fault that stretches from southern Idaho to central Utah, terminating near the town of Fayette.

Stress has built up over the years on the adjacent sides of the fault--one at the base of the mountain range and the other at the beginning of the valley. This is the result of prehistoric compression. As University of Utah seismologist Robert Smith describes it, it’s as if it’s being "slowly loaded like a stretched rubber band that suddenly breaks when its strength is exceeded."

The fault is capable of producing earthquakes of up to a 7.5 magnitude. This is concerning because 75% of the state’s population—a little over 2 million people—live in the four counties between Brigham City and Levan. This 150 mile stretch of the Wasatch Front has experienced the majority of earthquakes along the fault in the last 6,000 years.

Highly populated and developed cities such as Salt Lake City, Provo, and Ogden are among those at risk. But how likely is it that a major earthquake will strike the area sometime soon? Semiologists at the University of Utah say there is a 25% chance the area will experience a major quake--in the realm of 7.5 magnitude--in the next 50 years.

However, officials such as Joe Dougherty from the Utah Division of Emergency Management put the odds that the area will be hit by “The Big One” at 50% in the next 50 years.

American geologist G.K. Gilbert once wrote, “It is useless to ask when this [earthquake] disaster will occur. Our occupation of the country has been too brief for us to learn how fast the Wasatch grows; and, indeed, it is only by such disasters that we can learn. By the time experience has taught us this, Salt Lake City will have been shaken down…”

No matter if it’s a 25% or 50% likelihood, the truth of the matter is, we will never be 100% sure when it will strike--so better act as if it could happen at any moment and prepare accordingly.

The Effects of a Large Quake

First things first. Strong earthquakes can cause considerable damage up to nearly 50 miles from the earthquake. And because certain areas of Utah are built on valley fill versus hard rock, the shaking will only be amplified.

If a large earthquake were to occur along the Wasatch Fault, there would be a wide range of additional effects, such as landslides, rock falls, and flooding caused by the inundation of the Great Salt Lake or Utah Lake to parts of Salt Lake City or Provo.

What does this mean in terms of damage and casualties? Back in 2006, scientists predicted that a large quake would kill 6,200 people, injure 90,000 more, at least moderately damage 42 percent of all local buildings, and cause $40 billion in economic losses.

Even moderate earthquakes with a magnitude of 5.5 to 6.5 in an urban area can cause significant damage. According to the University of Utah, “Estimates of damage from a ‘direct hit’ to one of the Wasatch Front’s major metropolitan areas reach $2.3 billion for a magnitude 6.5 earthquake and more than $830 million for a magnitude 5.5 earthquake.”

Shaking would cause surface faulting and ground failures, resulting in major disruptions to utilities, water, sewage systems, transportation systems, and communication systems. Surviving the earthquake’s shaking is only the first step of survival. Persevering in the face of limited access to supplies and systems we use on a daily basis is the rest of the story.

What’s worse is that, unlike hurricanes and tornadoes, there is no “earthquake season,” which means that they can occur in a wide range of seasons and weather conditions. California may be at risk for a giant earthquake, but at least the majority of the state has a temperate climate. Utah, on the other hand, experiences cold winters. From November to March, the state is accustomed to freezing temperatures and plenty of snow.

This is significant because, if an earthquake were to strike during these colder months, survival without heat and power would be even more difficult. And it will take even longer for emergency vehicles and repairmen to make it out to people’s homes. Roads linking cities across western states are a small fraction compared to the eastern half of the country.

Preparation Tips

The silver lining associated with the occurrence of these recent smaller quakes in the state is that people are beginning to pay more attention to the threat of a larger quake. As a result, they are taking the time to learn how to prepare. If you’re looking to increase your odds of survival, keep the following three tips in mind...

#1: Know how to shelter in place: It’s not the quake itself that poses a threat to our lives: it’s what may happen to man-made structures such as bridges and buildings. The shaking can cause these structures to fall or collapse. Therefore, unless you’re out in the middle of a field, you’ll need to know how to shelter in place. When you feel shaking, be sure to drop down to your hands and knees and crawl to a shelter nearby without being knocked over. If a sturdy table or desk is nearby, crawl underneath it for shelter. If that’s not possible, crawl next to an interior wall away from windows. Stay on your knees and bend over to protect vital organs.

#2: Stock up on the essentials: Prepare an emergency kit to have at home or wherever you may be staying if you’re visiting. This should include essentials such as:

One to two gallons of drinking water per person per day for about two weeks, or at a minimum, three days. An at-home water filtration solution would also come in handy.
A nonperishable food supply
First aid supplies and essential prescription medications
A solar-powered radio and flashlight
Toilet paper and other hygiene products
Extra blankets and sleeping bags
Tools such as a hammer, tape, wrench, rope, etc.

You may also want to consider a backup generator, especially in the case of a quake occurring during winter temperatures.

#3: Remain aware and educated: Since 1850, at least 15 earthquakes with magnitudes of 5.5 or more have occurred along the Wasatch Front. The next one could be right around the corner--so don’t be caught off guard. Download emergency warning apps and stay up-to-date on specific protocols within your area.

Take the necessary steps to stock up and prepare now--whether you live in areas at risk or plan to visit one in the future.

In liberty,

Elizabeth Anderson

Preparedness Advisor, My Patriot Supply

Tags: Natural Disasters

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