Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Texas earthquake study cites 'plausible cause'

11.03.2010
Dallas-Fort Worth earthquakes coincident with activity associated with natural gas production

A study of seismic activity near Dallas/Fort Worth International Airport by researchers from Southern Methodist University and the University of Texas at Austin reveals that the operation of a saltwater injection disposal well in the area was a "plausible cause" for the series of small earthquakes that occurred in the area between Oct. 30, 2008, and May 16, 2009.

The incidents under study occurred in an area of North Texas where the vast Barnett Shale geological formation traps natural gas deposits in subsurface rock. Production in the Barnett Shale relies on the injection of pressurized water into the ground to crack open the gas-bearing rock, a process known as "hydraulic fracturing." Some of the injected water is recovered with the produced gas in the form of waste fluids that require disposal.

The earthquakes do not appear to be directly connected to the drilling, hydraulic fracturing or gas production in the Barnett Shale, the study concludes. However, re-injection of waste fluids into a zone below the Barnett Shale at the nearby saltwater disposal well began in September 2008, seven weeks before the first DFW earthquakes occurred and none were recorded in the area after the injection well stopped operating in August 2009.

The largest of the DFW-area earthquakes was a 3.3 magnitude event reported by the USGS National Earthquake Information Center.

A state tectonic map prepared by the Texas Bureau of Economic Geology shows a northeast-trending fault intersects the Dallas-Tarrant County line approximately at the location where the DFW quakes occurred. The study concludes, "It is plausible that the fluid injection in the southwest saltwater disposal well could have affected the in-situ tectonic stress regime on the fault, reactivating it and generating the DFW earthquakes."

An SMU team led by seismologists Brian Stump and Chris Hayward placed portable, broadband seismic monitoring equipment in the area after the earthquakes began. The seismographs recorded 11 earthquakes between Nov. 9, 2008 and Jan. 2, 2009 that were too small to be felt by area residents. Cliff Frohlich and Eric Potter of UT-Austin joined the SMU team in studying the DFW-area sequence of "felt" earthquakes as well as the 11 "non-felt" earthquakes. Their study appears in the March issue of The Leading Edge, a publication of the Society of Exploration Geophysicists.

The SMU team also installed temporary monitors in and around Cleburne, Texas where another series of small earthquake began June 2, 2009 – but results from that study are not yet available.

Stump and Hayward caution that the DFW study raises more questions than it answers.

"What we have is a correlation between seismicity, and the time and location of saltwater injection," Stump said. "What we don't have is complete information about the subsurface structure in the area – things like the porosity and permeability of the rock, the fluid path and how that might induce an earthquake."

"More than 200 saltwater disposal wells are active in the area of Barnett production," the study notes. "If the DFW earthquakes were caused by saltwater injection or other activities associated with producing gas, it is puzzling why there are only one or two areas of felt seismicity."

Further compounding the problem, Hayward said, is that there is not a good system in place to measure the naturally occurring seismicity in Texas: "We don't have a baseline for study."

Enhanced geothermal projects also rely on methods of rock fracturing and fluid circulation. Geological carbon sequestration, an approach being researched to combat climate change, calls for pumping large volumes of carbon dioxide into subsurface rock formations. "It's important we understand why and under what circumstances fluid injection sometimes causes small, felt earthquakes so that we can minimize their effects," Frohlich said.

The study notes that fault ruptures for typical induced earthquakes generally are too small to cause much damage.

"There needs to be collaboration between universities, the state of Texas, local government, the energy industry and possibly the federal government for study of this complicated question of induced seismicity," Stump said. "Everyone wants quick answers. What I can tell you is the direction these questions are leading us."

Find the full report at: http://smu.edu/newsinfo/pdf-files/earthquake-study-10march2010.pdf

View the report as posted by The Leading Edge at: http://dx.doi.org/10.1190/1.3353720

Report Authors:

Dr. Cliff Frohlich, Associate Director, Senior Research Scientist, Institute for Geophysics, UT-Austin
Eric Potter, Program Director, Bureau of Economic Geology, UT-Austin
Dr. Chris Hayward, Director, Geophysics Research Projects, Huffington Department of Earth Sciences, SMU

Dr. Brian Stump, Claude C. Albritton, Jr. Chair, Huffington Department of Earth Sciences, SMU

Kim Cobb | EurekAlert!
Further information:
http://www.smu.edu

More articles from Earth Sciences:

nachricht Colorado River's connection with the ocean was a punctuated affair
16.11.2017 | University of Oregon

nachricht Researchers create largest, longest multiphysics earthquake simulation to date
14.11.2017 | Gauss Centre for Supercomputing

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>