Parts of the central U.S. are at risk of a devastating magnitude 7 earthquake within the next 50 years, experts are warning, with added urgency due to what they say is a sense of ‘complacency’ in those areas.

Experts have been predicting a magnitude 7 earthquake in the areas surrounding the New Madrid fault line in Missouri for decades. It covers an area including Memphis, Tennessee, as well as St. Louis, Indianapolis and Little Rock, Arkansas

Despite 45 million people living within the danger zone, warnings have largely been ignored, said Robbie Myers, the emergency management expert from the region. 

The last major earthquakes from this fault happened in 1811 and 1812, centered near the town of New Madrid, Missouri. The quake reportedly managed to ring church bells as far away as South Carolina, causing farmland to sink into swamps and the Mississippi River to flow backward, among other strange occurrences. 

Myers, director of emergency management for Butler County, Missouri, told AP the biggest problem is complacency, as it is over 100 years since the last quake. 

If it were to hit today, he said thousands of people could potentially die, bridges crossing the Mississippi River could fall, major highways including Interstate 55 could buckle while oil and gas pipelines could break, causing nationwide disruptions.

Few residents of the area are concerned about earthquakes – which are traditionally considered a West Coast phenomenon in the U.S.  

But hundreds of emergency managers, transportation leaders, geologists and others gathered Thursday in St. Louis to discuss ways to improve preparations, looking at areas that have put procedures in place ‘just in case’ it happens.  

Most of the earthquake preparation in the U.S. has so far have been focused on California, which experts say is about 80 years overdue for ‘The Big One’, a massive earthquake where tectonic plates slide past each other along the 800-mile long San Andreas fault. 

This focus on California has made it harder for experts in Missouri to convince officials and the public to be prepared. When you add the fact that the last quake in Missouri was 100 years ago, they say, things get harder still. 

Researchers have also long debated just how much of a hazard New Madrid poses, with some earlier studies suggesting the fault was ‘dead’. The US Geological Survey, however, says this isn’t the case, and still predict a major quake.

The zone stretches 150 miles, crossing parts of Arkansas, Illinois, Indiana, Kentucky, Mississippi, Missouri and Tennessee, centered on the town of New Madrid.

In 1811 and 1812, it unleashed a trio of powerful jolts – measuring 7.5 to 7.7 – that rattled the central Mississippi River valley. The death toll is unknown, but experts don’t believe there were mass casualties because the region was sparsely populated.

Unlike California’s San Andreas and other faults that occur along boundaries of shifting tectonic plates, New Madrid is less understood since it’s in the middle of the continent, far from plate boundaries.

The USGS estimates there’s a 7 to 10 percent chance of a repeat of the 1811-1812 sequence happening in the next 50 years.

Experts also predict the chance of a magnitude 6 earthquake at as much as 40 percent by 2050. Smaller – but still potentially devastating. 

This will cause a bigger problem today, due to an increase in population. In Missouri alone the population has increased from 383, 702 in 1810, to over six million today.

The last time there was major attention paid to this fault line was in the 1990s, when climatologist Iben Browning said there was a 50-50 chance of a massive earthquake happening on December 3, 1990. Media arrived, but the quake ultimately didn’t happen.  

The Midwestern risk is ‘similar to the chances in California,’ said Thomas Pratt, Central and Eastern U.S. coordinator for the USGS Earthquake Hazards Program. 

Matthew Clutter, a Federal Emergency Management Agency operational planner, said a magnitude 7.7 earthquake in the New Madrid zone could displace nearly 850,000 people in up to eight states, including Illinois, Indiana, Missouri, Arkansas, Kentucky, Tennessee, and Mississippi. 

With roads and bridges compromised, emergency aid might be cut off from the impacted areas due to road and bridge damage.

‘If all eight states are affected there’s going to be a fight for resources,’ Clutter said.

Memphis, Tennessee, is within the zone. St. Louis, Indianapolis and Little Rock, Arkansas, are close enough for concern. In total about 45 million people live within the area that will be most impacted. 

Some communities have been more proactive than others in their preparations.

In Memphis, the Interstate 40 bridge into the city received a $260 million retrofit to protect against a strong earthquake. Building codes were upgraded a decade ago to require stricter construction standards with earthquake risk in mind.

In St. Louis, designers say the 29-story apartment tower overlooking Busch Stadium that opened in 2020 will sway rather than collapse in the event of a big quake. 

It’s the same engineering protection built into St. Louis’ most prominent landmark.

The Gateway Arch, completed in the 1960s, would sway up to 18 inches if an earthquake rumbles.

Meanwhile, a new St. Louis bridge over the Mississippi River that opened in 2014 was built with foundations all the way into bedrock to keep it steady and standing in the event of a quake. The region’s busiest river crossing, the Poplar Street Bridge, has been retrofitted for extra protection.

Still, most homes and commercial buildings within the region aren’t earthquake ready, according to emergency planners in the region.

‘Many places have no building codes, and very few of the existing building codes require earthquake-resistant design,’ a fact sheet from the American Geosciences Institute states.