It had been hidden for centuries – 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 December 16 quake was on what is now the border 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. 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 creation 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 recoded just in northwestern Crittenden County, ranging from Magnitude 4.7 to 6.8. Another major quake of Magnitude 7.3 occurred near New Madrid on January 23, 1812, followed an even more powerful quake of 7.5 on February 7. Nearly two hundred 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, picked up the name for these quakes. They 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 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. At the end of June, a small quake measuring 1.8 occurred near Blytheville, and at the beginning of July, a Magnitude 2.5 quake was detected near Pocahantas. Neither earthquake caused any damage or injuries and were hardly 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. With planning and careful attention to surroundings and warnings, the danger can be reduced. But the earthquakes remind us that the power of nature is not to be underestimated.
Dr. Ken Bridges is a professor of history and geography at South Arkansas Community College in El Dorado and a resident historian for the South Arkansas Historical Preservation Society. Bridges can be reached by email at firstname.lastname@example.org.