Earthquake shakes Tennessee near Missouri, Illinois, Arkansas, Kentucky border; 8th this week

The orange dot in the concentric circles marks the location of the epicenter of the earthquake that struck Tennessee today near the Kentucky/Illinois/Arkansas border. Image: USGS

Another earthquake shook Tennessee today, making it the 8th earthquake to hit the state in the past 7 days. Today’s earthquake struck three miles southeast of Tiptonville at a depth of 3.7 km at 1:34 a.m. local time; The USGS says it was a magnitude 2.1 event. Today’s earthquake struck a day after another relatively small magnitude 2.2 event hit the Mississippi River in Steele, Missouri. Today’s earthquake was the second strongest of the week, with the strongest hitting eastern Tennessee on August 22 with a magnitude of 2.3. None of the earthquakes caused damage in Tennessee this week.

As was the case with yesterday’s earthquake in Missouri, while today’s quake was inconsequential, authorities are concerned that people are not properly prepared for when a large tremor of earth will hit this area. The question of a larger destructive earthquake in this area is more a question of “when” than “if”.

Today’s earthquake occurred in the New Madrid Seismic Zone, or NMSZ for short. Today’s earthquake is the 51st to hit the region in the past 30 days, according to the USGS.

The New Madrid seismic zone remains active and another large earthquake strong enough to shake the entire eastern United States continues to loom.  Image: USGS
The New Madrid seismic zone remains active and another large earthquake strong enough to shake the entire eastern United States continues to loom. Image: USGS

The NMSZ has a violent history that experts say will repeat itself, although no one knows exactly when it will happen.

December 16 marks the anniversary of the first of three major earthquakes that struck the United States during the winter of 1811-1812, a violent period in the region’s seismological history that scientists say will will repeat again.

While the West Coast of the United States is well known for its seismic faults and powerful earthquakes, many are unaware that one of the largest earthquakes to hit the country occurred near the Mississippi River. . On December 16, 1811, at approximately 2:15 a.m., a powerful 8.1 magnitude earthquake shook northeastern Arkansas in what is now known as the New Madrid Earthquake Zone. The quake was felt across much of the eastern United States, shaking people out of bed in places like New York, Washington, DC and Charleston, SC. The ground shook for an incredibly long duration of 1-3 minutes in areas hard hit by the earthquake, such as Nashville, TN and Louisville, KY. Ground motions were so violent near the epicenter that ground liquefaction was observed, with soil and water being thrown into the air by tens of feet. President James Madison and his wife Dolly felt the quake at the White House as church bells rang in Boston from the tremors.

But the earthquakes did not stop there. From December 16, 1811 to March 1812, more than 2,000 earthquakes were reported in the central Midwest with 6,000 to 10,000 earthquakes located in Missouri’s “Bootheel”, where the New Madid seismic zone is centered .

Comparison of the extent of damage between a moderate earthquake in the New Madrid area (1895, magnitude 6.8) and a similar event in Los Angeles (1994, magnitude 6.7).  Yellow indicates where the tremors were felt;  red indicates at least minor damage to buildings and their contents.  Image: USGS
Comparison of the extent of damage between a moderate earthquake in the New Madrid area (1895, magnitude 6.8) and a similar event in Los Angeles (1994, magnitude 6.7). Yellow indicates where the tremors were felt; red indicates at least minor damage to buildings and their contents. Image: USGS

The second main shock, with a magnitude of 7.8, occurred in Missouri weeks later on January 23, 1812, and the third, an 8.8, struck on February 7, 1812, along the Reelfoot Fault in Missouri and Tennessee.

Major earthquakes and intense aftershocks caused significant damage and loss of life, although the lack of scientific tools and news gathering of that time was unable to capture the full magnitude of what had really happened. Beyond the tremors, the earthquakes were also responsible for triggering unusual natural phenomena in the region: seismic lights, seismic heated water, and seismic smog.

Residents of the Mississippi Valley reported seeing flashing lights from the ground. Scientists believe this phenomenon was “seismoluminescence”; this light is generated when quartz crystals in the ground are pressed. The “seismic lights” were triggered during primary earthquakes and strong aftershocks.

Since 1974, there have been more than 4,000 earthquakes near the New Madrid seismic zone.  Scientists believe that a big earthquake here in the future is not a matter of if but when.  Image: USGS
Since 1974, there have been more than 4,000 earthquakes near the New Madrid seismic zone. Scientists believe that a big earthquake here in the future is not a matter of if but when. Image: USGS

Water thrown into the air from the ground or the nearby Mississippi River was also exceptionally hot. The scientists speculate that intense shaking and the resulting friction caused the water to heat up, the same way a microwave oven stimulates molecules to shake and generate heat. Other scientists believe that when the quartz crystals were squeezed, the light they emitted also helped warm the water.

During strong earthquakes, the sky became so dark that locals claimed that burning lamps did not help illuminate the area; they also said the air smelled bad and it was hard to breathe. Scientists speculate that this “seismic smog” was caused by dust particles rising from the surface, combining with the eruption of hot water molecules into the cold winter air. The result was a wet, dusty cloud that obscured the areas affected by the earthquake.

The February earthquake was so intense that boaters on the Mississippi River reported that the water flow there reversed for several hours.

The area remains seismically active and scientists believe another strong earthquake will affect the area again at some point in the future. Unfortunately, the science is not mature enough to say whether this threat will arrive next week or in 50 years. Either way, with the population of the New Madrid earthquake zone huge compared to the sparsely populated area of ​​the early 1800s, and tens of millions more living in an area that would experience significant shaking in the ground, there could be a very significant loss of life and property. when another major earthquake strikes here again in the future.

The renewed activity around the New Madrid fault zone does not appear to be related to an ongoing earthquake swarm in South Carolina. There, since December 2021, more than 40 earthquakes have rocked central South Carolina, with several stronger earthquakes felt and measured in recent days. Scientists say the distance between the earthquakes in the New Madrid area and those in Elgin, South Carolina, is too far to be related.

There have been other recent earthquakes in Tennessee and Alabama. Although not directly related to each other, they are likely all part of the activity one would expect from the New Madrid seismic zone.

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