Minor earthquakes rattle Northeast Arkansas
Tremors a reminder of potential threat posed by New Madrid Faultline
firstname.lastname@example.org Jerry Lee Lewis once sang of “A Whole Lotta Shakin’ Goin’ On,” and there was a little bit of shakin’ goin’ on Thursday night not too far from Crittenden County.
The U.S. Geological Survey recorded an earthquake Thursday night in Randolph County, about 30 miles northwest of Jonesboro and 75 miles north of Marion.
The minor quake registered about 2.2 on the Richter Scale and was centered about 3.7 miles south of Black Rock. It was a “deep quake” according to the report, about 4.3 miles below the Earth’s surface.
While a minor earthquake, — no injuries, no reports of damage — it was the third quake along the New Madrid Faultline in less than a week. A magnitude 2.6 earthquake was recorded just five miles south of New Madrid, Missouri on Monday, Jan. 18, and even closer to home, a 2.8 tremor was registered by the U.S. Geological Survey in Mississippi County on Friday, Jan. 15. That quake hit 2.8 on the Richter Scale and was centered about 2 miles north of Blytheville, just 52 miles from Crittenden County and was even deeper than Thursday’s quake, at a depth of almost 7 miles underground. While again, no injuries were reported, several Blytheville residents felt the quake, with reports of a “loud boom” at the time of the earthquake.
Blytheville Mayor James Sanders told a Jonesboro news station that he had heard the boom and felt “a bit of a jolt.”
In an eerie coincidence, Saturday was the 209th anniversary of the Magnitude 7.3 earthquake that occurred near New Madrid on Jan. 23, 1812, followed by an even more powerful quake of 7.5 on Feb. 7. Nearly 200 major aftershocks of more than Magnitude 4.0 rattled the region into March, with hundreds more affecting the whole area. The largest settlement near the epicenter, the small town of New Madrid, Missouri, is where the faultline got its name.
The 1812 series of quakes had been forecast just a month earlier. Dr. Kenneth Bridges, a frequent contributor to the “Arkansas History Minute,” recalled that violent quake.
“It had been hidden for centuries,” said Bridges.
“A horrendous force of nature that would terrify the frontier. In the dead of a cold December night in 1811, a violent earthquake erupted, centered in what is now northeast Arkansas and southeast Missouri. In a matter of moments, homes collapsed and lives were shattered in what became known as the New Madrid Earthquake. But this first earthquake would be far from the last, and it would have lasting effects.” The epicenter of the Dec.
16, 1811 quake was on what is now the border of Missouri and Mississippi County in northeast Arkansas. Geologists later estimated the strength of the earthquake at around Magnitude 7.7 on the Richter scale, an earthquake intensity scale developed in the 1930s by California geologist Charles Richter.
Quakes registering at 2.0 or less are almost never even felt. Only about a dozen quakes measuring greater than 7.0 are measured each year, and quakes beyond 8.0 cause catastrophic damage. The shock wave carried so far away from the area that damage was recorded in Ohio, and it was felt in New York City, more than a thousand miles away.
“Only one death was reported,” said Bridges.
“The injury total is unknown. In the midst of the quake, not only did the flimsy cabins built by settlers collapse, but the earthquake altered the landscape. Landslides were recorded, and even some lands sunk. Islands in the area sunk under the seismic pressures and others were formed. River flow was altered, resulting in the cre-
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ation of St. Francis Lake.”
Six hours after the main quake, just as dawn was breaking, a massive aftershock struck. This new earthquake was centered just northwest of what is now Marked Tree in Poinsett County and had an estimated strength of 7.0. A chain reaction of hundreds of other aftershocks followed. Forty-nine aftershocks were recorded just in northwestern Crittenden County, ranging from Magnitude 4.7 to 6.8.
The New Madrid is one of the most well-known major faultlines. Faultlines are caused by a crack in the Earth, known as an intraplate fault line, where tremendous pressures build up over time. The pressures are released by earthquakes, usually occurring miles beneath the surface.
The fault line runs from Poinsett County across to Mississippi County to New Madrid, roughly parallel to the Missouri-Tennessee-Kentucky border on the Mississippi River.
In 1815, Congress passed the New Madrid Act. As part of an early federal effort to help victims of natural disasters rebuild their lives, Congress offered new federal lands to allow the settlers to rebuild their broken lives.
Accepting these New Madrid Certificates, as they were called, thousands of people moved from the area, mostly deeper into areas of Arkansas and Missouri. The aftereffects of the New Madrid quakes actually led to the increased population of Arkansas in the years before it was established as a territory. There have been many earthquakes in the region since the disasters of 1811 and 1812. In 1843, a Magnitude 6.2 quake occurred in Poinsett County. A Magnitude 5.0 quake occurred in Mississippi County in 1878. Three magnitude 4 earthquakes were recorded in eastern Lawrence County in 1918. An earthquake measuring 5.0 on the Richter scale occurred between Trumann and Marked Tree in Poinsett County in March 1976, causing power outages and broken windows across Jonesboro and as far away as Paragould, nearly 40 miles away.
Earthquakes have been detected far from northeast Arkansas. In fact, most counties in Arkansas have experienced earthquakes, though most are so subtle or centered so far below the surface that they are never noticed.
However, a sizable tremblor of 4.7 was recorded in Cleveland County in 1911.
Quakes greater than Magnitude 4.0 were recorded near Malvern in 1930 and El Dorado in 1939. A quake of magnitude 4.5 was recorded in Pulaski County in 1969. Two quakes of similar strength were felt in Clark County in 1974. A series of earthquakes occurred near Enola, just north of Conway, in Faulkner County in January 1982.
Hundreds of quakes under Magnitude 2.0 were recorded in the weeks that followed, called the “Enola Swarm” by geologists. The highest was 4.5, but no major damage or injuries were reported. A Magnitude 4.7 quake was recorded in 2011.
“Dozens of earthquakes are recorded across Arkansas each year,” said Bridges.
“Fortunately, most cause no damage or are even noticed. The New Madrid quakes are still the worst quakes recorded east of the Rocky Mountains.
Geologists rate the area along the New Madrid Fault at high risk for another major quake in the next 50 years.”
A major quake in the region would no doubt cause much more damage and have a much greater potential loss of life now after more than 200 years of popluation growth and development.
“With planning and careful attention to surroundings and warnings, the danger can be reduced,” said Bridges, “but these earthquakes remind us that the power of nature is not to be underestimated.”