Tag: Matthew J. Hornbach

Dallas Morning News: Mounting evidence suggests Dallas quakes are induced by human activity

Post author By Margaret Allen
Post date January 5, 2016

Evidence that human activity is behind the Dallas quakes includes a new analysis showing that the faults beneath Dallas and Fort Worth had been dormant for hundreds of millions of years until 2008.

SMU seismologists presented new earthquake findings at the American Geophysical Union annual meeting. (Credit: DMN)

Science journalist Anna Kuchment with The Dallas Morning News covered the comments of SMU seismologists Heather DeShon and Beatrice Magnani speaking during the annual American Geophysical Union meeting in San Francisco, Calif. DeShon and Magnani presented their latest research on North Texas ground shaking.

The SMU seismology team, which includes DeShon and Magnani, published new evidence of human involvement in earthquakes in Nature Communications in April 2015. Their data showed that large volumes of wastewater injection combined with saltwater (brine) extraction from natural gas wells is the most likely cause of earthquakes near Azle, Texas, from late 2013 through spring 2014.

The Dallas Morning News article published Dec. 16, 2015.

Read the full story.

EXCERPT:

By Anna Kuchment
The Dallas Morning News
Scientists presented new evidence this week suggesting that all five North Texas earthquake sequences, including those in Dallas, have been triggered by humans.

Until now, researchers have not commented on the cause of the Dallas-Irving quakes or the 4-magnitude quake that struck Venus, 30 miles south of Dallas, in May.

While scientists believe that high-volume injection wells may have triggered the quakes in Venus, they have not yet worked out a specific mechanism behind the Dallas and Irving quakes.

“We don’t think they’re natural,” SMU seismologist Heather DeShon told The Dallas Morning News. “But we don’t understand the subsurface physics surrounding the Irving earthquake sequence, so we’re still considering all causes.”

DeShon’s comments came during the annual American Geophysical Union meeting in San Francisco, where she and her colleagues presented their latest research on North Texas ground shaking. The research has not yet been independently vetted and published.

“Any discussion of causation for the Dallas-area quakes is premature, and more speculative than scientific,” said Steve Everley, a senior advisor for Energy In Depth, a program of the Independent Petroleum Association of America. “But the SMU team has helped advance our understanding of the conditions that can ultimately lead to induced seismicity, so we’re eager to see what they will publish about the seismic events near Dallas.”

Read the full story.

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Tags Beatrice Magnani, Brian W. Stump, Chris Hayward, Dedman College, Heather R. DeShon, Matthew J. Hornbach, Roy M. Huffington Department of Earth Sciences

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SMU seismology team to cooperate with state, federal scientists in study of May 7 Venus, Texas earthquake

Post author By Margaret Allen
Post date May 8, 2015

Scientists had been observing smaller quakes in area; SMU seismology team has developed expertise to deploy instruments, analyze and sharedata

SMU’s seismology team was not surprised by the magnitude 4.0 earthquake that occurred near Venus, Texas, Thursday evening, having been aware of multiple smaller earthquakes identified by the United States Geological Survey (USGS) in the area in recent months. They are recommending a regional monitoring network.

“We emphasized to the House Committee on Energy Resources the need for a permanent regional network, supplemented by portable instruments, that we can deploy in a time-sensitive manner when earthquakes occur,” said Matthew Hornbach, SMU associate professor of geophysics.

“The seismology team at SMU has developed the expertise to deploy these instruments, analyze and share that data,” said Brian Stump, SMU Albritton Chair of Geological Sciences. “We are committed to cooperate, as resources allow, with both state and federal agencies in addressing these issues,” Stump said.

Currently SMU has 26 seismic instruments deployed in North Texas, split between an area near Azle, Texas, SMU, earthquakes, seismology that experienced a series of earthquakes from late 2013 through spring 2014, and along a fault straddling the Irving-Dallas, Texas, earthquakes, SMU, seismology line where earthquakes have been occurring near the site of the old Texas Stadium.

“We are in the process of determining what resources might be available so that we can respond to the largest earthquake now felt in North Texas,” said Heather DeShon, SMU associate professor of geophysics. Previous SMU deployments have relied heavily on loaned monitoring equipment from the USGS and the academic consortium known as IRIS – Incorporated Research Institutions for Seismology. “We are still in the process of determining how many instruments might be available for this purpose in light of ongoing earthquake activity around the world, such as the recent earthquake in Nepal,” DeShon said.

The magnitude 4.0 earthquake (M4) recorded by the USGS in Venus at 5:58 p.m. Thursday is part of a series of smaller earthquakes the SMU team has been following in the Midlothian area. The National Earthquake Information Center (NEIC) has reported seven earthquakes within 10 kilometers of the USGS location for the May 7 Venus earthquake, with three of them (including the most recent) occurring at or above magnitude 3. There have been 23 earthquakes recorded within 20 kilometers of the Venus location, since 2009, with five of them registering higher than an M3.

SMU first started studying earthquakes in Johnson County for a series of earthquakes occurring in Cleburne in 2009, culminating in the peer reviewed “Analysis of the Cleburne, Texas, Earthquake Sequence from June 2009 to June 2010 (doi: 10.1785/0120120336 Bulletin of the Seismological Society of America October 2013). The SMU team also is watching with interest an additional area of seismicity (based on USGS locations) near Mineral Wells.

“I don’t think any of us was surprised by Thursday’s event,” DeShon said. “There have been a series of magnitude 3 and greater earthquakes in the Johnson County area. If you have movement on a fault and change the stresses, you increase the likelihood of additional earthquakes. In other words, one earthquake frequently leads to another.”

The SMU team noted that the USGS web site for the event contains an analysis of the data that estimates fault motion striking from the northeast to the southwest – consistent with other earthquake sequences SMU has studied in North Texas.

“This illustrates that we all need to think about the possibility of larger earthquakes in the region where we live,” Stump said. — Kimberly Cobb

Tags Beatrice Magnani, Brian W. Stump, Chris Hayward, Dedman College, Heather R. DeShon, Matthew J. Hornbach, Roy M. Huffington Department of Earth Sciences

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WFAA 8 ABC: Geologists release details of Azle earthquakes study

Post author By Margaret Allen
Post date April 22, 2015

Injecting fluids into the ground or extracting them has long been known to cause quakes, but rarely — if ever — have the two been caught acting in concert.

WFAA 8 ABC news reporter Byron Harris reported on the SMU-led team of seismologists whose recent study found that large volumes of wastewater injection combined with saltwater (brine) extraction from natural gas wells is the most likely cause of earthquakes near Azle, Texas, from late 2013 through spring 2014.

The study published in Nature Communications.

WFAA aired their segment, Geologists release details of Azle earthquakes study, April, 21, 2015.

Read the full story.

EXCERPT:

By Byron Harris
WFAA 8 ABC
The seismology team led by SMU that has been researching local earthquakes believes it’s found a cause for the ones that hit Azle a couple of years ago.

“Causal Factors for Seismicity near Azle, Texas” was published in Nature Communications. A press release about the findings of the study was released on Tuesday.

It states that the team at SMU found “high volumes of wastewater injection combined with saltwater (brine) extraction from natural gas wells is the most likely cause of earthquakes.”

Oil and gas drilling takes water out of the ground as a product of energy production. And that water is pumped back into the ground in wastewater injection wells. SMU geologists measured those activities, centered around the Newark East Gas Field north and east of Azle.

They found 70 energy-producing wells in the field, and two adjacent wastewater injection wells. Increased levels of water injection and withdrawal corresponded with the earthquakes, the report says.

The quakes hit Azle between late 2013 and spring of 2014. The town saw seven quakes of magnitude 3.0 or higher in that period. A 3D model was developed to investigate two intersecting faults and estimate stress changes.

Read the full story.

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Tags Beatrice Magnani, Brian W. Stump, Chris Hayward, Dedman College, Heather R. DeShon, Matthew J. Hornbach, Roy M. Huffington Department of Earth Sciences

Earth & Climate Energy & Matter Researcher news SMU In The News

Dallas Morning News: Azle earthquakes likely caused by oil and gas operations, study says

Post author By Margaret Allen
Post date April 21, 2015

Injecting fluids into the ground or extracting them has long been known to cause quakes, but rarely — if ever — have the two been caught acting in concert.

A sign marks the entrance to an EnerVest wellsite in Parker County. SMU researchers detemined that an EnerVest wastewater well was one of two such sites exerting the greatest pressure on the fault where earthquakes occurred starting in November 2013. Workers buried about 120 million gallons of fluid at the site between October 2010 and September 2013. (DMN)

Science journalist Anna Kuchment with The Dallas Morning News covered the research of an SMU-led team of seismologists whose recent study found that large volumes of wastewater injection combined with saltwater (brine) extraction from natural gas wells is the most likely cause of earthquakes near Azle, Texas, from late 2013 through spring 2014.

The study published in Nature Communications.

The Dallas Morning News article published April, 21, 2015.

Read the full story.

EXCERPT:

By Anna Kuchment
The Dallas Morning News
Oil and gas operations are the most likely cause of dozens of earthquakes that began rattling the North Texas towns of Azle and Reno in November 2013, a group of scientists has concluded.

The study, led by researchers at SMU and published Tuesday in the journal Nature Communications, presents some of the most conclusive evidence yet that humans are shifting faults below Dallas-Fort Worth that have not budged in hundreds of millions of years.

While experts have not yet determined what’s causing the shaking in Dallas and Irving, the new paper previews aspects of that study and includes suggestions that will help speed research.

“It’s certainly one of the best cases in the literature,” said Art McGarr of the U.S. Geological Survey’s Earthquake Hazards Program in Menlo Park, Calif.

The new findings contradict statements by the Railroad Commission of Texas that there are no definitive links between oil and gas activity and earthquakes in the state.

Shown an embargoed version of the paper, the commission’s staff seismologist Craig Pearson wrote in a statement that “the study raises many questions with regard to its methodology, the information used and conclusions it reaches.” But he declined to answer specific questions before meeting with the paper’s authors. The Railroad Commission regulates the oil and gas industry.

The Azle study is the result of a yearlong collaboration involving 11 researchers at SMU, the University of Texas at Austin, and the U.S. Geological Survey and was reviewed by independent experts before publication.

The scientists zeroed in on an unusual mechanism behind the quakes: workers pushing liquid into the ground on one side of a fault and sucking gas and groundwater from the other side of the fault.

“The combination of these activities seems to have triggered the earthquakes, and that was a real surprise to us,” said Matthew Hornbach, a geophysicist at SMU and a lead author of the paper.

Injecting fluids into the ground or extracting them has long been known to cause quakes, but rarely — if ever — have the two been caught acting in concert.

The geology of each region is unique, however, so these mechanisms may not be at work elsewhere.

Read the full story.

Follow SMUResearch.com on twitter at @smuresearch.

Tags Beatrice Magnani, Brian W. Stump, Chris Hayward, Dedman College, Heather R. DeShon, Matthew J. Hornbach, Roy M. Huffington Department of Earth Sciences

Earth & Climate Energy & Matter Researcher news

Most likely cause of 2013-14 earthquakes: Combination of gas field fluid injection, removal

Post author By Margaret Allen
Post date April 21, 2015

SMU-led seismology team reveals Azle findings for an area where the seismology team identified two intersecting faults

Natural and anthropogenic stress changes that may trigger earthquakes in the Azle area. (SMU) — Natural and man-made stress changes that may trigger earthquakes in the Azle area. (SMU)

An SMU-led seismology team finds that high volumes of wastewater injection combined with saltwater (brine) extraction from natural gas wells is the most likely cause of earthquakes occurring near Azle, Texas, from late 2013 through spring 2014.

In an area where the seismology team identified two intersecting faults, they developed a sophisticated 3D model to assess the changing fluid pressure within the rock formation. They used the model to estimate stress changes induced in the area by two wastewater injection wells and the more than 70 production wells that remove both natural gas and significant volumes of salty water known as brine.

Conclusions from the modeling study integrate a broad-range of estimates for uncertain subsurface conditions. Ultimately, better information on fluid volumes, flow parameters, and subsurface pressures in the region will provide more accurate estimates of the fluid pressure along this fault.

“The model shows that a pressure differential develops along one of the faults as a combined result of high fluid injection rates to the west and high water removal rates to the east,” said Matthew Hornbach, SMU associate professor of geophysics. “When we ran the model over a 10-year period through a wide range of parameters, it predicted pressure changes significant enough to trigger earthquakes on faults that are already stressed.”

Modelled pressure changes in the Ellenburger caused by injection and production. The images show the system prior to injection (a) through the onset of seismicity (e). Note that the most significant amount of brine removal occurs along the fault trend.

Model-predicted stress changes on the fault were typically tens to thousands of times larger than stress changes associated with water level fluctuations caused by the recent Texas drought.

“What we refer to as induced seismicity – earthquakes caused by something other than strictly natural forces – is often associated with subsurface pressure changes,” said Heather DeShon, SMU associate professor of geophysics. “We can rule out stress changes induced by local water table changes. While some uncertainties remain, it is unlikely that natural increases to tectonic stresses led to these events.”

Surprisingly small changes in stress can reactivate certain faults
DeShon explained that some ancient faults in the region are more susceptible to movement – “near critically stressed” – due to their orientation and direction. “In other words, surprisingly small changes in stress can reactivate certain faults in the region and cause earthquakes,” DeShon said.

The study, “Causal Factors for Seismicity near Azle, Texas,” has been published in the journal Nature Communications. The study was produced by a team of scientists from SMU’s Roy M. Huffington Department of Earth Sciences in Dedman College of Humanities and Sciences, the U.S. Geological Survey, the University of Texas Institute for Geophysics and the University of Texas Department of Petroleum and Geosystems Engineering. SMU scientists Hornbach and DeShon are the lead authors.

Fluid pressure modeling of industry activity and water table fluctuations is first of its kind
SMU seismologists have been studying earthquakes in North Texas since 2008, when the first series of felt tremors hit near DFW International Airport between Oct. 30, 2008, and May 16, 2009. Next came a series of quakes in Cleburne between June 2009 and June 2010, and this third series in the Azle-Reno area northwest of Fort Worth occurred between Nov. 2013 and Jan. 2014. The SMU team also is studying an ongoing series of earthquakes in the Irving-Dallas area that began in April 2014.

In both the DFW sequence and the Cleburne sequence, the operation of injection wells used in the disposal of natural gas production fluids was listed as a possible cause of the seismicity. The introduction of fluid pressure modeling of both industry activity and water table fluctuations in the Azle study represents the first of its kind, and has allowed the SMU team to move beyond assessment of possible causes to the most likely cause identified in this report.

Prior to the DFW Airport earthquakes in 2008, an earthquake large enough to be felt had not been reported in the Fort Worth Basin since 1950. The North Texas earthquakes of the last seven years have all occurred in areas developed for natural gas extraction from a geologic formation known as the Barnett Shale. The Texas Railroad Commission reports that production in the Barnett Shale grew exponentially from 216 million cubic feet a day in 2000, to 4.4 billion cubic feet a day in 2008, to a peak of 5.74 billion cubic feet of gas a day in 2012.

Read the report here.

While the SMU Azle study adds to the growing body of evidence connecting some injection wells and, to a lesser extent, some oil and gas production to induced earthquakes, SMU’s team notes that there are many thousands of injection and/or production wells that are not associated with earthquakes.

The area of study addressed in the report is in the Newark East Gas Field (NEGF), north and east of Azle. In this field, hydraulic fracturing is applied to loosen and extract gas trapped in the Barnett Shale, a sedimentary rock formation formed approximately 350 million years ago. The report explains that along with natural gas, production wells in the Azle area of the NEGF can also bring to the surface significant volumes of water from the highly permeable Ellenburger Formation – both naturally occurring brine as well as fluids that were introduced during the fracking process.

Subsurface fluid pressures are known to play a key role in causing seismicity. A primer produced by the U.S. Department of Energy explains the interplay of fluids and faults:

The fluid pressure in the pores and fractures of the rocks is called the ‘pore pressure.’ The pore pressure acts against the weight of the rock and the forces holding the rock together (stresses due to tectonic forces). If the pore pressures are low (especially compared to the forces holding the rock together), then only the imbalance of natural in situ earth stresses will cause an occasional earthquake. If, however, pore pressures increase, then it would take less of an imbalance of in situ stresses to cause an earthquake, thus accelerating earthquake activity. This type of failure…is called shear failure.

Injecting fluids into the subsurface is one way of increasing the pore pressure and causing faults and fractures to “fail” more easily, thus inducing an earthquake, he said. Thus, induced seismicity can be caused by injecting fluid into the subsurface or by extracting fluids at a rate that causes subsidence and/or slippage along planes of weakness in the earth.

All seismic waveform data used in the compilation of the report are publically available at the IRIS Data Management Center. Wastewater injection, brine production and surface injection pressure data are publicly available at the Texas Railroad Commission (TRC). Craig Pearson at the TRC, Bob Patterson from the Upper Trinity Groundwater Conservation District; scientists at XTO Energy, ExxonMobil, MorningStar Partners and EnerVest provided valuable discussions and, in some instances, data used in the completion of the report.

“This report points to the need for even more study in connection with earthquakes in North Texas,” said Brian Stump, SMU’s Albritton Chair in Earth Sciences. “Industry is an important source for key data, and the scope of the research needed to understand these earthquakes requires government support at multiple levels.” — Kimberly Cobb

Follow SMUResearch.com on twitter at @smuresearch.

Tags Beatrice Magnani, Brian W. Stump, Chris Hayward, Dedman College, Heather R. DeShon, Matthew J. Hornbach, Roy M. Huffington Department of Earth Sciences

Evidence that human activity is behind the Dallas quakes includes a new analysis showing that the faults beneath Dallas and Fort Worth had been dormant for hundreds of millions of years until 2008.

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Scientists had been observing smaller quakes in area; SMU seismology team has developed expertise to deploy instruments, analyze and sharedata

Injecting fluids into the ground or extracting them has long been known to cause quakes, but rarely — if ever — have the two been caught acting in concert.

Book a live interview

Related links

More SMU Research news

Injecting fluids into the ground or extracting them has long been known to cause quakes, but rarely — if ever — have the two been caught acting in concert.

Book a live interview

Related links

More SMU Research news

SMU-led seismology team reveals Azle findings for an area where the seismology team identified two intersecting faults

Book a live interview

Related links

More SMU Research news