Ten days Later & we have a (4.7) ARKANSAS
UPDATED CNN Video Report:
~ The VERY strange part is 3.5 Magnitude Earthquake Felt on Dauphin Island, Gulf Shores, AL. People from Dauphin Island, Gulf Shores and Fort Morgan began calling emergency officials after the ground began shaking around 5:15 p.m.
Intellicast earthquake map … .North-central Arkansas has been rattled with a number of small earthquakes in the past several days, including two that registered 3.5 and 3.8 and some officials and residents wonder if there is any relation to natural gas injection wells.
A magnitude 3.5 earthquake struck in north central Arkansas around 3:46 p.m. Central time on Wednesday, February 16, following a series of small quakes that have been rattling the area for the past few days. The United States Geological Survey website showed the location of this quake as being approximately three miles northeast of Greenbrier and four miles southwest of Guy.
A 3.8 quake was registered on Thursday at 4:49 a.m. Central time in the same area. The earthquakes are being called the Guy earthquake swarm, according to an Associated Press report. Earthquake swarms are small earthquakes occurring in the same location in close succession and the current swarm has registered more than 30 earthquakes. Another earthquake swarm occurred around the same location in October 2010 with the largest of the quakes measuring 4.0 on October 11. The current swarm of earthquakes has ranged in size between 2.1 and 3.8 in magnitude.
This area of Arkansas is not located within the actual New Madrid seismic one but is situated to the west. The New Madrid seismic zone stretches from Cairo, Illinois, southwest to Marked Tree, Arkansas. Marked Tree is about 200 miles northeast of Guy. An earthquake along the New Madrid fault would affect this part of Arkansas, but some local residents and even scientists believe the quakes could be due to human activities.
A geohazards supervisor with the Arkansas State Geological Survey, Scott Ausbrooks, told the Associated Press that this Arkansas earthquake swarm could be related to natural gas exploration in the area. The area where the earthquakes have been occurring is part of the Fayetteville Shale–an area of rich organic rock in north-central Arkansas. The Fayetteville Shale area has more than 400 completed gas wells.
According to the AP report, the actual production wells may not be the issue, but rather the injection wells. The gas is freed by drillers using a method known as “fracking. This hydraulic fracturing injects pressurized water into the ground to fracture the earth and release the natural gas. Injections wells are created when leftover frac water (wastewater from the initial fracking that can no longer be used) is pressurized and injected into the ground. According to the Environmental Protection Agency, an injection well is “a device that places fluid deep underground into porous rock formations, such as sandstone or limestone, or into or below the shallow soil layer. These fluids may be water, wastewater, brine (salt water), or water mixed with chemicals.”
The AP reported that the earthquakes in the current swarm are located near several injection wells. Ausbrooks also told AP it is “unlikely” the area would experience earthquakes larger in magnitude than 5.0.