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Houston Chronicle: New data shows North Texas fault line

It is significant that underground conditions have changed to trigger slips on a fault line that hasn’t moved in human memory.

Houston Chronicle, earthquakes, SMU, DeShon, Stump

Journalist Dylan Baddour covered the recent interim report about the research findings of Southern Methodist University’s seismology team surrounding a recent series of earthquakes in the Irving, Texas area.

His Houston Chronicle report, “New data shows North Texas fault line,” covered the preliminary findings and the progress on the team’s earthquake research.

Initial results reveal that the earthquakes that occurred near the site of the old Texas Stadium were relatively shallow and concentrated along a narrow two mile line that indicates a fault extending from Irving into West Dallas.

SMU and the United States Geological Survey shared the report with the mayors of Dallas and Irving spelling out preliminary information gleaned after SMU’s installation in January of more than 20 portable earthquake monitors around the earthquake sites. SMU seismologists Heather DeShon and Brian Stump, in the Roy M. Huffington Department of Earth Sciences, answered questions during the briefing with reporters.

The article published Feb. 11, 2015.

Read the full story.

EXCERPT:

By Dylan Baddour
Houston Chronicle

North Texas earthquake swarms still baffle geologists, who never expected to study seismic tremors in the Lone Star State. But last month scientists installed equipment to record quakes near Irving, Texas, and last week the first numbers came in.

We still don’t know much about why the region shakes, but here’s what we just learned: the quakes have all been relatively shallow, and have centered along a newly-identified fault line near Irving. The data is thanks 20 seismic monitoring machines, supplied by the U.S. Geological Survey and deployed by scientists from Texas’ Southern Methodist University last month.

“This is a first step, but an important one, in investigating the cause of the earthquakes,” said SMU seismologist Brian Stump. “Now that we know the fault’s location and depth, we can begin studying how this fault moves – both the amount and direction of motion.”

Irving, just north of Dallas, shook first in April 2014, but the area’s strongest quakes struck last month. The so-called “earthquake swarm” follows others since 2008 that have hit North Texas—a region with no history of seismic action. This year, the USGS announced plans to raise the region’s official earthquake risk level. Still, no one knows why the region has started to tremble.

“The two views about them. One: in 150 years there haven’t been natural earthquakes in the Dallas-Fort Worth area, so if these earthquakes were natural, that’s very interesting,” said Cliff Frolich, a geologist at the University of Texas at Austin and a veteran researcher of the North Texas quakes. “On the other hand the earthquakes that occurred in 2008 and subsequently appear to be close to injection wells. The fact that these earthquakes are occurring only a few years later, some people would probably conclude they are related to oil and gas activities.”

Injection wells are where oil and gas drillers dispose of tens of millions of gallons of toxic wastewater left over from hydraulic fracturing, or “fracking,” an extraction technique that’s proliferated in Texas and across the country since 2008. Some scientists have suggested that pressure put on fault lines by high-powered injection into bedrock could trigger the quakes, but nothing is conclusive.

Read the full story.

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SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smu.edu.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.

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Dallas Morning News: Remap of Dallas-area quakes shows fault closer to fracking wells than thought

Now that SMU’s seismology team has located the fissure, they can begin to study how and why it’s moving.

Dallas Morning News, SMU, earthquakes, Irving, Anna Kuchment, Heather DeShon, Brian Stump

Science journalist Anna Kuchment covered a recent interim report on the research findings of Southern Methodist University’s seismology team surrounding a recent series of earthquakes in the Irving, Texas area.

Kuchment’s Dallas Morning News article, “Remap of Dallas-area quakes shows fault closer to fracking wells than thought,” covered a briefing with the press on Friday, Feb. 6, to explain progress on the team’s earthquake research.

Initial results reveal that the earthquakes that occurred near the site of the old Texas Stadium were relatively shallow and concentrated along a narrow two mile line that indicates a fault extending from Irving into West Dallas.

SMU and the United States Geological Survey shared the report with the mayors of Dallas and Irving spelling out preliminary information gleaned after SMU’s installation in January of more than 20 portable earthquake monitors around the earthquake sites. SMU seismologists Heather DeShon and Brian Stump, in the Roy M. Huffington Department of Earth Sciences, answered questions during the briefing with reporters.

Read the full story.

EXCERPT:

By Anna Kuchment and Avi Selk
Dallas Morning News

Scientists finally have a rough picture of the ancient fault that’s been rattling the Dallas area, and the fissure isn’t where the public thought it was.

Armed with more equipment and better data, SMU scientists have relocated dozens of quakes on the federal government’s imprecise maps. The team released a new map on Friday that shifts the epicenters of nearly all of last month’s temblors, arranging them in a neat line that shadows a fissure miles beneath the earth.

And while the team has just begun to study that fault, they already have some early hints about its nature.

It’s not beneath the old Texas Stadium site, as federal maps suggested.

It’s small (for a fault) and appears to be quieting down after tossing off about four dozen quakes in a year. But it could still produce a tremor much more powerful than any Dallas has yet seen.

And while scientists are skeptical that gas drilling woke it up, they now know the fault runs much closer than previously thought to the only two fracking wells in the area.

If you’ve felt any of the earthquakes to hit the Dallas area since last fall, you may have looked up a map of their epicenters. The rough bull’s eye of quakes around the old Texas Stadium site has sparked wild theories about the stadium’s demolition and jokes about the “Jerry Jones Fault.”

That map is wrong, and scientists have always known it.

The federal government estimated the North Texas epicenters using a small handful of quake detectors, some of which sat miles away and produced inaccurate readings.

The U.S. Geological Survey’s blob of approximate quake locations was of little use to scientists trying to map the underground crack producing them. So in early January, the SMU team began to install nearly two dozen detectors in the Irving area to collect more accurate data.

The earth obliged with more than two dozen quakes since then, including the most powerful yet in Dallas County.

Read the full story.

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SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smu.edu.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.

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Earth & Climate Energy & Matter

SMU analysis of recent North Texas earthquake sequence reveals geologic fault, epicenters in Irving and West Dallas

Shallow depths explain why so many felt relatively small quakes; not unusual for earthquakes to occur at different fault levels.

Locations of seismic instruments as of Jan. 30, 2015, with revised earthquake locations in dark red. (USGS)
Locations of seismic instruments as of Jan. 30, 2015, with revised earthquake locations in dark red. (USGS)

Initial results from the seismology team at Southern Methodist University reveal that a recent series of North Texas earthquakes occurring near the site of the old Texas Stadium in the Dallas-Fort Worth area were relatively shallow and concentrated along a narrow two mile line that indicates a fault extending from Irving into West Dallas.

SMU and the United States Geological Survey on Friday, Feb. 6, 2015 shared an interim report with the mayors of Dallas and Irving spelling out preliminary information gleaned after SMU’s installation in January of more than 20 portable earthquake monitors around the earthquake sites.

“This is a first step, but an important one, in investigating the cause of the earthquakes,” said SMU seismologist Brian Stump. “Now that we know the fault’s location and depth, we can begin studying how this fault moves — both the amount and direction of motion.”

“Then we can move on to what might have triggered it – examining factors both natural and manmade,” said SMU seismologist Heather DeShon. “Sometimes what triggers an earthquake can be very small, so all of these factors have to be considered when looking for that trigger.”

The earthquakes have occurred in the granite “basement,” below the layers of sedimentary rock that make up the large geological formation known as the Fort Worth Basin, at depths between 4.5 and 7 kilometers, according to the report. It is not unusual for earthquakes to occur at different levels on a fault. Those depths are considered relatively close to the surface in earthquake terms, however, which helps explain why people as far away as the northern suburb of Plano feel even smaller magnitude 2 earthquakes in the area.

January 2015 earthquakes actually have occurred along a line from Irving to West Dallas
The USGS initially mapped the earthquake locations as being spread out in a roughly circular area centered on the old Texas Stadium site, developing those locations from data collected by distant seismic monitors ranging from the closest at about 40 miles away to as far as 900 miles away. But once SMU installed more than 20 monitors in the immediate area – supplied by the USGS and the academic consortium IRIS – the enhanced data they were able to retrieve shows the January 2015 earthquakes actually have occurred along a line from Irving to West Dallas, running north-by-northeast from TX Highway 114 to Walnut Hill Road along the Trinity River.

That line indicates the approximate location of a subsurface fault.

This initial mapping of the fault provides important information for municipal hazard assessment in Irving and Dallas, Stump said, allowing city officials to know which parts of their cities might experience the worst shaking if the fault remains active. As has been the case with other earthquake sequences in North Texas since 2008, this latest bout of seismic activity appears to be diminishing over time. But SMU scientists stress that there is no way to predict when the series will end, or what the largest magnitude will be.

The earthquakes in the Irving area began in April 2014. SMU scientists had just installed the first of its local monitors in the city of Irving on Jan. 5, 2015 when the area recorded its two largest earthquakes – 3.5 and 3.6 magnitude events – on Jan. 6.

SMU seismology team installed more than 20 seismographs in the affected area
During January, members of the SMU seismology team installed more than 20 seismographs in the affected area, including 12 short-term units that had to be removed from the field to collect their data. There will be 11 temporary seismographs running as part of the Irving network moving forward.

The report notes the presence of two wells drilled for shale gas (only one was put into production, last producing in 2012) near the earthquake epicenters and the location of a wastewater injection well approximately eight miles to the northwest. Production and disposal activities in this region are generally confined to the sedimentary layers above the “basement” layers where regional earthquakes have occurred.

“Scientific questions about the nature of events in North Texas have heightened local and national concerns about the impact of activities related to shale gas production on geological infrastructure and subsurface infrastructure,” the report reads. “SMU scientists continue to explore all possible natural and anthropogenic (due to human activity) causes for the Irving earthquakes and do not have a conclusion at this time.”

The next steps of the Irving study already are underway.

Signing the report were Heather DeShon, SMU associate professor of geophysics; Brian Stump, SMU Albritton Chair of Geological Sciences; Chris Hayward, senior scientist and director of SMU’s Geophysics Research Program; Beatrice Magnani, SMU associate professor of geophysics; Matthew Hornbach, SMU associate professor of geophysics; and Robert Williams and Michael Blanpied of the USGS Earthquake Hazards Program. — Kimberly Cobb

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SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smu.edu.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.

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NBC News: Climate-changing methane ‘rapidly destabilizing’ off East Coast, study finds

Methane hydrate samples.

NBC News has covered the research of SMU marine geologist Matthew Hornbach, who led the study that has uncovered a powerful new way to use data from the geological record to discover non-anthropogenic climate changes underway.

The study suggests warmer temperatures are destabilizing up to 2.5 gigatonnes of methane hydrate along the continental slope of the eastern United States.

Co-author on the study is SMU geophysics doctoral student Benjamin Phrampus.

The researchers say it isn’t clear if the methane will release, but the gas would have the potential to rise up through the ocean and into the atmosphere, where it would add to the greenhouse gases warming Earth.

From the study, the authors write:
“Here, using seismic data combined with thermal models, we show that recent changes in intermediate-depth ocean temperature associated with the Gulf Stream are rapidly destabilizing methane hydrate along a broad swathe of the North American margin. The area of active hydrate destabilization covers at least 10,000 square kilometres of the United States eastern margin, and occurs in a region prone to kilometre-scale slope failures. Previous hypothetical studies, postulated that an increase of five degrees Celsius in intermediate-depth ocean temperatures could release enough methane to explain extreme global warming events like the Palaeocene–Eocene thermal maximum (PETM) and trigger widespread ocean acidification. Our analysis suggests that changes in Gulf Stream flow or temperature within the past 5,000 years or so are warming the western North Atlantic margin by up to eight degrees Celsius and are now triggering the destabilization of 2.5 gigatonnes of methane hydrate (about 0.2 per cent of that required to cause the PETM).”

Read the full article.

EXCERPT:

By Miguel Llanos
NBC News

A changing Gulf Stream off the East Coast has destabilized frozen methane deposits trapped under nearly 4,000 square miles of seafloor, scientists reported Wednesday. And since methane is even more potent than carbon dioxide as a global warming gas, the researchers said, any large-scale release could have significant climate impacts.

Temperature changes in the Gulf Stream are “rapidly destabilizing methane hydrate along a broad swathe of the North American margin,” the experts said in a study published Wednesday in the peer-reviewed journal Nature.

Using seismic records and ocean models, the team estimated that 2.5 gigatonnes of frozen methane hydrate are being destabilized and could separate into methane gas and water.

It is not clear if that is happening yet, but that methane gas would have the potential to rise up through the ocean and into the atmosphere, where it would add to the greenhouse gases warming Earth.

The 2.5 gigatonnes isn’t enough to trigger a sudden climate shift, but the team worries that other areas around the globe might be seeing a similar destabilization.

“It is unlikely that the western North Atlantic margin is the only area experiencing changing ocean currents,” they noted. “Our estimate … may therefore represent only a fraction of the methane hydrate currently destabilizing globally.”

The wider destabilization evidence, co-author Ben Phrampus told NBC News, includes data from the Arctic and Alaska’s northern slope in the Beaufort Sea.

Read the full article.

Follow SMU Research on Twitter, @smuresearch.

For more SMU research see www.smuresearch.com.

SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information, www.smu.edu.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.

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Nature: Seismic signs of escaping methane under the sea

A changing Gulf Stream is warming deep waters along the eastern United States and destabilizing greenhouse gases trapped in sediments.

Sand is not the only thing on the move in the waters off the eastern United States — a shift in the Gulf Stream is melting methane hydrate in sediments that could release methane gas.
(Image: D. Harvey/Natl. Geographic/Getty Images)

Nature magazine covered the research of SMU marine geologist Matthew Hornbach, who led the study that has uncovered a powerful new way to use data from the geological record to discover non-anthropogenic climate changes underway.

The study suggests warmer temperatures are destabilizing up to 2.5 gigatonnes of methane hydrate along the continental slope of the eastern United States.

From the study, the authors write:
“Here, using seismic data combined with thermal models, we show that recent changes in intermediate-depth ocean temperature associated with the Gulf Stream are rapidly destabilizing methane hydrate along a broad swathe of the North American margin. The area of active hydrate destabilization covers at least 10,000 square kilometres of the United States eastern margin, and occurs in a region prone to kilometre-scale slope failures. Previous hypothetical studies, postulated that an increase of five degrees Celsius in intermediate-depth ocean temperatures could release enough methane to explain extreme global warming events like the Palaeocene–Eocene thermal maximum (PETM) and trigger widespread ocean acidification. Our analysis suggests that changes in Gulf Stream flow or temperature within the past 5,000 years or so are warming the western North Atlantic margin by up to eight degrees Celsius and are now triggering the destabilization of 2.5 gigatonnes of methane hydrate (about 0.2 per cent of that required to cause the PETM).”

Co-author on the study is SMU geophysics doctoral student Benjamin Phrampus.

Read the full article.

EXCERPT:

By Virginia Gewin
Nature

Somewhere off the eastern coast of North Carolina, a frozen mixture of water and methane gas tucked in seabed sediments is starting to break down. Researchers blame a shifting Gulf Stream — the swift Atlantic Ocean current that flows north from the Gulf of Mexico — which is now delivering warmer waters to areas that had previously only experienced colder temperatures.

“We know methane hydrates exist here and, if warming continues, it can potentially lead to less stable sediments in this region,” says Matthew Hornbach, a marine geologist at the Southern Methodist University in Dallas, Texas, who led the study that is published online today in Nature1. The results suggest that the warmer temperatures are destabilizing up to 2.5 gigatonnes of methane hydrate along the continental slope of the eastern United States. This region is prone to underwater landslides, which could release the methane, a powerful greenhouse gas.

Whether that methane would make it to the atmosphere and worsen global warming is unclear, but scientists think that it is unlikely. “We don’t need to worry about any huge blow of methane into the atmosphere,” says Carolyn Ruppel, a geophysicist at the US Geological Survey in Woods Hole, Massachusetts. Rather, she says, Hornbach and his co-author Benjamin Phrampus, also of the Southern Methodist University, have uncovered a powerful new way to use data from the geological record to catch non-anthropogenic climate changes that are already happening.

Read the full article.

Follow SMU Research on Twitter, @smuresearch.

For more SMU research see www.smuresearch.com.

SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information, www.smu.edu.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.