Louisiana Names Sinkhole Study Group as Tremors Recur

The head of Louisiana’s Department of Natural Resources has named 13 scientists and other experts to serve on a commission to determine the long-term stability of the area around northern Assumption Parish’s sinkhole.

The 13-acre sinkhole and fears of a methane explosion have forced evacuation of 350 residents for more than seven months.

The sinkhole, discovered Aug. 3, is believed to have been caused by a failed Texas Brine Co. LLC cavern.

Members of the panel will set up scientific benchmarks and determine when they’ve been met, signaling it’s safe for residents to return, The Advocate reports.

Underscoring concerns about the growing sinkhole and its instability, more seismic activity forced parish officials Friday to halt work in the area for the second time in little more than a week.

John Boudreaux, Assumption Parish’s director of Homeland Security and Emergency Preparedness, said the seismic activity was detected about 7 a.m. Friday under the sinkhole and the failed Texas Brine cavern.

Seismic monitors detected an increase Friday in the “very long period” tremors that scientists have said indicate fluid and gas movement below the sinkhole, parish officials wrote in a blog post.

Parish officials added that Friday’s seismic activity was limited to the sinkhole and the Texas Brine cavern. The activity appears to have had no effect on a second Texas Brine cavern nearby for which structural concerns recently have been raised, parish officials said.

Water movement in the sinkhole and increased bubbling along its western edge were also detected Friday, the post says.

Boudreaux said work was stopped within the 71-acre area surrounded by a berm mandated to encircle the sinkhole. The shutdown area took in the sinkhole’s lake-like surface.

He said crews had been working on oil retardant boom on the sinkhole at the time the work was stopped about 8:30 a.m. Friday.

But he said work related to underground seismic surveying – which involves firing small, buried explosive charges – continued Friday because it is outside the berm area.

Gov. Bobby Jindal called for formation of the commission earlier this month after meeting with Assumption Parish officials and Texas Brine executives about the sinkhole.

Panel members include some experts who already have been working on the sinkhole, as well as some new scientists.

DNR officials said in a statement that the blue-ribbon commission’s first meeting will be held in early April. Patrick Courreges, DNR spokesman, has said some of the group’s meetings would be public, but it was not clear Friday if the panel’s inaugural session would be public or not.