The largest earthquake event in Arkansas in 35 years was recorded Sunday at 11 p.m. near Greenbrier.

An initial register of magnitude 4.7 was not downgraded Monday, placing it at No. 1 in rank among what geologists have dubbed the “Guy Swarm.”

Sunday’s event exceeds a previously recorded quake of 4.1 that was felt countywide on Feb. 18.

According to the U.S. Geological Survey, the epicenter of the quake was 4 miles northeast of Greenbrier.

Geohazards Specialist Scott Ausbrooks of the Arkansas Geological Survey, said that the epicenter lay in close proximity of two natural gas industry injection wells.

“The epicenter was relatively close. There are two injection sites nearby, one at the epicenter’s south end and one on its north end,” Ausbrooks said.

Ausbrooks said that the Arkansas Geological Survey’s Geohazards division is investigating a possible link between injection wells and increased seismicity in the area, after ruling out excavation activity as a cause.

“We will be looking at data from the wells and more data is coming. We’re receiving figures on a two-week basis where we were getting it once a month,” said Ausbrooks.

Ausbrooks said that the injection well to the north of the quake’s epicenter is owned by Chesapeake Energy Corp., and the well located to the south, Clarita Operating.

Ausbrooks said that reports on the U.S. Geological Survey’s “Did you feel it?” website were typical of a 4.7 magnitude.

“You will see on the map on the website that reports came from a good part of the state. There are around 5,000 responses,” Ausbrooks said.

The AGS received damage reports of cracked sheet rock, broken shelf items and a broken window associated with the event.

“This is typical with what we expect with a 4.5 to a 4.7 earthquake. In this range we see broken windows, cracked plaster. People are awakened and people are frightened.”

LaTresha Woodruff, public information officer for the Conway Police Department, said that 9-1-1 dispatchers received 51 calls from concerned residents just after 11 p.m. Sunday.

(Staff writer Courtney Spradlin can be reached by e-mail at or by phone at 505-1236. To comment on this and other stories in the Log Cabin, log on to Send us your news at