The northeast section of Arkansas is located in the New Madrid seismic zone and was seriously affected by great shocks that occurred in that zone, in 1811 - 1812. Arkansas' 40-mile-long, half-mile-wide Lake Saint Francis was formed by these earthquakes.
The Mississippi embayment - fall line area, in which the New Madrid seismic zone is located, extends from Cairo, Illinois, south through northeastern Arkansas, western Kentucky, and Tennessee, then westward to include the lowland area of southern Arkansas, the eastern Oklahoma - Texas border area, and northeastern Texas. Major historic seismic activity has been limited to a line extending west of the Mississippi River, from Cairo to west of Memphis. Several damaging earthquakes have occurred along this line, in addition to the New Madrid shocks mentioned earlier. Indian tradition and geologic evidence indicate an earlier history of severe earthquakes in the same area.
Outside the Mississippi Embayment, the first shock listed for Arkansas occurred in October 1882. Since few reports were received from the region most affected, the epicenter of this shock is not well known, and several investigators have placed the origin near El Reno, Oklahoma, instead of western Arkansas. The shock threw bricks from chimneys at Sherman, Texas, and shook houses strongly at Fort Smith, Arkansas. Its felt area covered parts or all of Arkansas, Oklahoma, Kansas, Texas, and Missouri, about 135,000 square miles.
An earthquake occurred near Melbourne, about 95 miles northeast of Little Rock, in December 1883. Rockslides occurred on a railroad cut, and thunderous earth noises were heard. Glassware and crockery broke, and buildings shook at Melbourne.
A shock in March, 1911, about 40 miles south of Little Rock, was so severe at Pine Bluff that hundreds of excited residents crowded into the streets in panic; windows were broken in several sections of the city. At one school, walls cracked, and plaster fell on pupils. "Glasses were shaken from counters in confectionery stores, and dishes were broken in many kitchens," the record notes. The shock was felt throughout southeastern Arkansas and in adjacent States.
During the period 1911 to 1933, two local intensity V earthquakes centered in the Black Rock - Pocahontas area of northeastern Arkansas; two additional intensity V tremors were noted, one near Little Rock, the other near Marked Tree, and both were felt over 30,000 square mile areas. None of these caused property damage, but they alarmed much of the populations near their centers.
The early morning of December 9, 1933, brought another minor tremor to Arkansas. Many residents of Manila, Mississippi County, were awakened by a sharp earthquake that broke windows in several homes.
Very light tremors in 1937 and 1938 in the northeastern part of Arkansas were felt over 25,000 and 90,000 square miles of Arkansas and several surrounding States. Neither was damaging. This region is noted for relatively light-intensity shocks being felt over extremely large areas.
One of the few earthquakes to center in southwestern Arkansas occurred in June 1939. It cracked plaster in buildings at Arkadelphia, and was felt throughout the southern portion of Arkansas.
After the 1939 earthquake, only light tremors (all under intensity V) were noted until January 25, 1955. The 1955 tremor centered in northeastern Arkansas near the Missouri - Tennessee border, and caused some property damage in the bordering States. At Dyersburg, Tennessee, a brick pillar supporting a porch was thrown down; at Finley, plaster, walls, and ceilings cracked. Windows cracked in the small town of Hayti, Missouri. Thousands of residents over a 30,000 square mile area were awakened by this early morning event.
Arkansas was again relatively quiescent seismically for 14 years, until New Year's Day of 1969. During this period, however, three shocks in northeastern Texas and southern Missouri caused some damage in Arkansas. The strongest of the three centered in southeastern Missouri in March 1963. It cracked windows, plaster, concrete, and walls in several Arkansas towns.
On January 1, 1969, a tremor centered about 19 miles northwest of Little Rock and caused much commotion in the area. In Little Rock, plaster cracked, and furniture was moved about in some homes; and trees and utility wires swayed and shook throughout a wide area. The shock was also noted by residents in southern Missouri and western Tennessee.
Abridged from Earthquake Information Bulletin, Volume 2, Number 4, July-August 1970.
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