'We're Really Not Supposed to Have Earthquakes Here'

A map put out by the US Geological Society earlier this year on earthquake risk zones has a lot of red in unsurprising places such as California and Alaska. But as a story at the nonprofit science site Undark points out, it also has what amounts to a bull's-eye over ... Missouri? The small town of New Madrid, Missouri, to be precise. The town is the locus for what is known as the New Madrid Seismic Zone, a region that encompasses not only Missouri but parts of Tennessee, Kentucky, Illinois, and Arkansas. Big cities within this area include St. Louis and Memphis. Residents may be surprised to learn that the USGS estimates the zone has a 25% to 40% of a 6.0-magnitude quake or higher in the next 50 years. Worse, the agency estimates a 10% risk that the zone will see a repeat of a devastating set of earthquakes that rattled the region in 1811 and 1812.

The story by Freda Kreir details how the small town dropped at least 15 feet at the time—and how things would be much worse today in a region where millions of people live in houses that for the most part are not equipped to withstand earthquakes. "It's really one of the most enigmatic seismic zones on the planet," says Eric Sandvol, a seismologist at the University of Missouri. "We're not supposed to have earthquakes here." The region is "smack dab in the middle of a tectonic plate," notes Kreir, and thus not an obvious candidate. And yet, scientists say the region has seen a 7.0-magnitude quake or higher every 500 years for thousands of years. The story explores possible reasons—"ancient fault lines" may be at play—as well as how cities are preparing for a worse-case scenario. Read it in full here. (Or read more longform recaps.)