Two Days Of Shaking Give Towns The Jitters

Agency Seeks Clues To Quake Cluster

A series of earthquakes near three Arkansas towns Tuesday and Wednesday, including two by Morrilton, have geologists studying causes and residents wary of the potential for more shaking.

At least 14 quakes rumbled near Morrilton, Damascus and Strawberry within two days, said Scott Ausbrooks, geohazards supervisor for the Arkansas Geological Survey.

The largest, a 3.5-magnitude, occurred at 12:19 p.m. Wednesday about 10 miles north of Morrilton. That temblor was preceded by a 2.3 in the same area at 9:21 a.m. Wednesday.

No injuries or damage was reported in any of the earthquakes.

“We don’t know yet what caused them,” Ausbrooks said. “It could be natural, or it could be man-made.”

An active injection well used by a natural-gas drilling company shoots wastewater from drilling operations into a well about 8 miles from where the quakes were centered, he said. Geologists have said drilling operations contributed to hundreds of earthquakes near Conway and Faulkner counties over the past few years.

Ausbrooks said the shaking also could be natural. Wednesday’s quakes near Morrilton occurred along a bend in a fault system beneath Conway County where rumblings are more apt to occur naturally.

Five quakes were recorded around Damascus - including 2.1-, 2.0- and 1.9-magnitude ones - early Tuesday morning.

In Strawberry, a small Lawrence County town about 20 miles northeast of Batesville, seven small temblors were recorded between 4:28 a.m. and 9:11 a.m Tuesday.

Gary Patterson, a geologist at the Center for Earthquake Research and Information in Memphis, suspects the Strawberry quakes occurred naturally on a fault system that has produced other shaking in the past. On Feb. 27, 1979, seven quakes were monitored in the same area and earned the designation as the “Strawberry Swarm,” Patterson said.

“We’re looking at our previous data from Strawberry,” he said. “It’s odd that nearly 30 years ago, on the first day of the ‘swarm,’ they had seven earthquakes, and on Tuesday they had seven again.”

Shawnia Pettit, an employee of the Strawberry Super Shop convenience store, said she didn’t feel Tuesday’s quakes but heard people discuss them at the store.

“It’s ironic,” she said. “I lived in California, and we left there because of the earthquakes and moved here.”

She said she was somewhat apprehensive about the earth’s movements lately.

“It makes me wonder what’s going to happen,” she said.

Morrilton Mayor Stewart Nelson knew his town was perched atop a fault system when workers began building a city swimming pool and bathhouse. An architect told him that construction codes were different because the town was in an earthquake fault zone.

“We’ve got some old buildings downtown that, if we have a good quake, I’ll have a brickyard left over,” he said. “But my biggest concern is that we have two natural-gas pipelines running through. If an earthquake were to rupture one, we’d have a hell of a fire.”

Patterson said he will continue to monitor the three areas. He said the quakes were not related - the quakes in one area did not trigger those in the other areas.

Northwest Arkansas, Pages 7 on 05/23/2013

Upcoming Events