Dozens of people used the USGS website’s “Did you feel it?” reporting tool to report shaking they felt from earthquakes that rattled Kentucky and Tennessee last night. The epicenter of the three earthquakes wasn’t far from the center of the New Madrid Seismic Zone, or NMSZ for short.
The first earthquake struck near Ridgely, Tennessee at 8:49 pm last night. At a depth of 6.6 km, the magnitude 2.6 earthquake was too weak to create any damage or injuries.
The second earthquake was substantially stronger than the first, but was also generally weak in the scheme of things and also caused no damage nor injuries. That magnitude 3.0 event struck near Calhoun, Kentucky at 9:45 pm from a depth of 6 km.
The third earthquake happened just 4 minutes after the prior one; a magnitude 2.5 quake struck in nearly the same location as the earlier Calhoun, Kentucky earthquake. This quake was very shallow though, with USGS reporting a depth of only 0.7 km.
While last night’s earthquakes were relatively inconsequential with no damage reports, authorities are concerned that people aren’t properly prepared for when a big earthquake will strike this region. The matter of a larger destructive earthquake in this area is more of a matter of “when” rather than “if.” These earthquake in Tennessee in particular was within the New Madrid Seismic Zone, or NMSZ for short; while it and the other two quakes were far from significant, they struck in an area where a significant earthquake will happen again at some point in the future.The NMSZ has a violent history that experts say will repeat itself, although no one is sure when it’ll happen.
December 16 marks the anniversary of the first of three major quakes to strike the United States during the winter of 1811-1812, a violent time in seismological history of the region that scientists say will be repeated again.
While the US West Coast is well known for its seismic faults and potent quakes, many aren’t aware that one of the largest quakes to strike the country actually occurred near the Mississippi River.
On December 16, 1811, at roughly 2:15am, a powerful 8.1 quake rocked northeast Arkansas in what is now known as the New Madrid Seismic Zone. The earthquake was felt over much of the eastern United States, shaking people out of bed in places like New York City, Washington, DC, and Charleston, SC. The ground shook for an unbelievably long 1-3 minutes in areas hit hard by the quake, such as Nashville, TN and Louisville, KY. Ground movements were so violent near the epicenter that liquefaction of the ground was observed, with dirt and water thrown into the air by tens of feet. President James Madison and his wife Dolly felt the quake in the White House while church bells rang in Boston due to the shaking there.
But the quakes didn’t end there. From December 16, 1811 through to March of 1812, there were over 2,000 earthquakes reported in the central Midwest with 6,000-10,000 earthquakes located in the “Bootheel” of Missouri where the New Madid Seismic Zone is centered.
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