Increased seismic activity recorded at giant Louisiana sinkhole

Source: Assumption Parish Office of Homeland Security and Emergency Preparedness
Source: Assumption Parish Office of Homeland Security and Emergency Preparedness

BAYOU CORNE, LA (WAFB) - According to the Assumption Parish Police Jury website, increased seismic activity was recorded between 6 p.m. and midnight, Tuesday. The cause of this activity is unknown at this time. The tremors occurred on the same day dangerous gases were discovered at one of the vent wells at the sinkhole.

Texas-Brine submitted a proposal to the Department of Natural Resources Wednesday afternoon to immediately and permanently shut down a vent well after a dangerous gas was detected at the well site.

Tuesday, Texas Brine reported high levels of Hydrogen Sulfide in a vent well that is drilled into the cap rock at the giant sinkhole near Grand Bayou and Bayou Corne.

Hydrogen Sulfide is a poisonous, flammable gas and has a very bad odor. The smell is described as the smell of rotten eggs. Unlike methane, it is heavier than air and collects at low to the ground levels. No community air monitors have detected Hydrogen Sulfide.

The well was shut down due to these levels. This vent well is the deepest vent well on the property. The Department of Natural Resources' contractor, The Shaw Group, is currently investigating. Assumption Parish officials are currently waiting on additional details from DNR.

Texas Brine put up a safety perimeter around the well, including use of barricades and gas monitors, under the oversight of Conservation staff on site.

The well that could be shut down is the deepest of the wells being used to vent the natural gases. This well was drilled down to about 480 feet. It goes into the caprock that sits on top of the compromised salt dome.

The top of the cavern lies about 3,400 feet below the surface. Venting natural gas is a part of the plan to deal with the cause of the sinkhole and natural gas bubbling in the area.

DEQ and Assumption Parish OEP will continue its daily monitoring of the air quality and gas bubbles to make sure levels are safe.

In the meantime, DEQ is doing in-home monitoring, but residents tell WAFB 9News they believe nothing will be done until someone dies.

Copyright 2012 WAFB. All rights reserved.