The question, of course, is whether or not this enigmatic zone will be brought to life again, underneath a region of the US that has millions more in the firing line than there was in 1812. A major earthquake could potentially threaten swaths of at least seven states – Illinois, Indiana, Missouri, Arkansas, Kentucky, Tennessee, and Mississippi – along this 240-kilometer (150-mile) fault system. One study suggests that a repeat today would displace 7.2 million people and cause infrastructural damage amounting to around $300 billion.
As noted by the United States Geological Survey (USGS), this zone is somewhat active, noting that the region has accumulated high amounts of stress. “It is the most seismically active area of the United States east of the Rockies,” they write in a 2009 report. Looking for surface deformation is perhaps a red herring, though – unlike fault zones, which regularly push the surface around even during the period between major quakes – the NMSZ will likely show little deformation until a major rupture occurs.
They conclude that, based on the available GPS data, that the 1811-1812 quakes have a recurrence time of around 500 years, so we should not expect the next sizeable one – around a magnitude 7.0 – until around the year 2300. However, they do warn that there is still a 10 percent chance that it will occur in the next 50 years. The chance of having a magnitude 6.0 quake along the NMSZ in the same time frame is up to 40 percent likely.
Memphis, Tennessee is right in the firing line. Natalia Bratslavsky/Shutterstock
It must be noted that there’s plenty of debate as to how active or dormant the NMSZ is, but it’s quite unlikely that a catastrophe in the Midwest is due anytime in the next few lifetimes. So when you see somewhat overhyped and overexcited headlines claiming that the “clock is ticking,” remember that the clock in question is likely to be ticking very slowly indeed.
[H/T: The Atlantic]