Gas-charged fluids creating seismicity associated with a Louisiana sinkhole

Jun 30, 2014

Natural earthquakes and nuclear explosions produce seismic waves that register on seismic monitoring networks around the globe, allowing the scientific community to pinpoint the location of the events. In order to distinguish seismic waves produced by a variety of activities – from traffic to mining to explosions – scientists study the seismic waves generated by as many types of events as possible.

In August 2012, the emergence of a very large sinkhole at the Napoleonville Salt Dome in Louisiana offered University of California, Berkeley scientists the opportunity to detect, locate and analyze a rich sequence of 62 seismic events that occurred one day prior to its discovery.

In June 2012, residents of Bayou Corne reported frequent tremors and unusual gas bubbling in local surface water. The U.S. Geological Survey installed a temporary network of , and on August 3, a large sinkhole was discovered close to the western edge of the salt dome.

In this study published by the Bulletin of the Seismological Society of America (BSSA), co-authors Douglas Dreger and Avinash Nayak, evaluated the data recorded by the during the 24 hours prior to the discovery of the sinkhole. They implemented a waveform scanning approach to continuously detect, locate and analyze the source of the seismic events at the sinkhole, which are located to the edge of the salt dome and above and to the west of the cavern near the sinkhole.

The point-source equivalent force system describing the motions at the seismic source (called moment tensor) showed similarities to produced by explosions and active geothermal and volcanic environments. But at the sinkhole, an influx of natural gas rather than hot magma may be responsible for elevating the pore pressure enough to destabilize pre-existing zones of weakness, such as fractures or faults at the edge of the salt dome.

Explore further: Network for tracking earthquakes exposes glacier activity

More information: The paper, "Moment Tensor Inversion of Seismic Events Associated with the Sinkhole at Napoleonville Salt Dome, Louisiana," will be published online July 1, 2014, and published in the August print edition of BSSA.

add to favorites email to friend print save as pdf

Related Stories

Network for tracking earthquakes exposes glacier activity

May 01, 2014

Alaska's seismic network records thousands of quakes produced by glaciers, capturing valuable data that scientists could use to better understand their behavior, but instead their seismic signals are set aside as oddities. ...

Homing in on a potential pre-quake signal

Aug 02, 2012

In a new analysis of the 2004 magnitude 6.0 Parkfield earthquake in California, David Schaff suggests some limits on how changes measured by ambient seismic noise could be used as a pre-earthquake signal.

NASA radar demonstrates ability to foresee sinkholes

Mar 07, 2014

(Phys.org) —New analyses of NASA airborne radar data collected in 2012 reveal the radar detected indications of a huge sinkhole before it collapsed and forced evacuations near Bayou Corne, La., that year.

3-D Earth model more accurately pinpoints explosions

Oct 28, 2013

During the Cold War, U.S. and international monitoring agencies could detect nuclear tests and measure their size. Today, they seek to pinpoint much smaller explosives tests. Under the sponsorship of the ...

Recommended for you

Scientists make strides in tsunami warning since 2004

22 hours ago

The 2004 tsunami led to greater global cooperation and improved techniques for detecting waves that could reach faraway shores, even though scientists still cannot predict when an earthquake will strike.

Trade winds ventilate the tropical oceans

22 hours ago

Long-term observations indicate that the oxygen minimum zones in the tropical oceans have expanded in recent decades. The reason is still unknown. Now scientists at the GEOMAR Helmholtz Centre for Ocean Research ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

seth_york
1 / 5 (1) Jul 01, 2014
phys.org can stuff itself. Texas brine stored oil high in H2S on the northwest side of the salt dome next to pressurized butane. The hydrogen sulfide reacted with the oxides in the ground to create water and elemental sulfur to create the sinkhole. Then, the day before Thanksgiving '12; it gave way pushing the oil north and northwest causing a worldwide endothermic reaction that almost reversed the Earth's electromagnetic current. This would have reacted with ungrounded currents like crossed jumper cables, melting and exploding them. I seriously doubt anything would have survived had this happened.

H2S and iron oxide lead to water and elemental sulfur in an endothermic reaction. By setting up these reactions insulated from the ground, the ungrounded EM currents gave up the oxides and returned water back to the Earth's EM current. In essence, blood sacrifice to volcanoes was emulated to stop reverse polarity from turning Earth into another Venus.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.