Geologists raise Arkansas fault’s estimated size

NWA:

LITTLE ROCK — Geologists say a previously unmapped fault that is the source of a swarm of earthquakes around Guy and Greenbrier in Faulkner County is longer and potentially more destructive than they initially believed.

Prompted by growing knowledge of the fault, the Arkansas Oil and Gas Commission last week ordered a halt to operations at two disposal wells in Faulkner County that commission staff think might be linked to the seismic activity.

The injection wells operated by Chesapeake Operating Inc. and Clarita Operating LLC contain discarded fluid used to drill for natural gas in the Fayetteville Shale.

In the five days since the injections were stopped Thursday, the number of the biggest quakes - those over magnitude 2.5 - has decreased.