Earthquake Information

July 26, 2016:  TexNet begins deploying earthquake monitoring equipment (The Daily Texan)

July 25, 2016:  Scientists offer possible explanation for how oil and gas activity may have triggered Dallas earthquakes (Dallas Morning News)

May 23, 2016: View the April 2016 Project Update from the TexNet CISR.

May 18, 2016: UT study: Fracking-related activities have caused majority of recent Texas earthquakes (Dallas Morning News)

March 28, 2016: The City of Irving has remained at the forefront of efforts to apply state resources and expertise to studying seismic issues in North Texas. Irving played a major role in convincing the state to fund equipment and a seismic study during the 2015legislative session. That $4.5 million, appropriated to the Bureau of Economic Geology (BEG) at UT Austin, is being used to coordinate information already available, place new monitoring equipment in the field and hire staff who will conduct a study for presentation to the governor and the legislature this December.

In addition, Irving City Manager Chris Hillman was appointed by Gov. Greg Abbott to the committee that will oversee the seismic study, ensuring timely communication with the study team and results for residents of Irving and North Texas.

The study is likely to be the first in an ongoing series of efforts by the BEG to better understand seismic activity in Texas.

What does the USGS Induced Seismicity Hazard Map mean to me?
In anticipation of questions, the USGS has released a list of Frequently Asked Questions. Visit www.usgs.gov. For scientific earthquake definitions visit the USGS glossary page at http://earthquake.usgs.gov/learn/glossary/.

Is there fracking in Irving?

No. Only two wells have been drilled in Irving. One was never completed to production status and the other was shut-in in 2010. “Shut-in” is an industry term which means to close the valves so a well stops producing.

Are there wastewater injection wells in Irving?

There never have been wastewater injection wells in Irving.

What can Irving residents do about induced earthquakes?
The best thing to do is to be prepared. The map stands as a reminder that earthquakes occur. Scientists cannot predict when they will happen or how intense they will be. Visit these sites for preparedness tips:
For additional questions, contact Jessica Fitzpatrick at jkfitzpatrick@usgs.gov and copy Sue Perry at scperry@usgs.gov.
Jan. 13, 2016: State will begin to install earthquake monitors in the spring (Ft. Worth Star-Telegram)
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Scientists Discuss Earthquakes

Dec. 17, 2015: At the recent annual American Geophysical Union meeting,  Southern Methodist University (SMU) scientists reported they believe the Dallas/Irving quakes have been triggered by human activity. They said they have not determined causation. The seismologists continue to study data from 11 seismometers located in Irving and Dallas.

The City of Irving continues working closely with the University of Texas Austin’s Bureau of Economic Geology (BEG) as well. Last session the legislature allocated $4.47 million for the TexNet Seismic Monitoring Program, which the BEG will lead and will include seismologists from across the state. The BEG has hired staff, all of whom will be in place in early January. The seismic network is expected to be deployed soon thereafter.

There is no fracking in Irving, and there are no wastewater injection wells located here. For more information on the American Geophysical Union meeting click here.
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Oct. 7: The City of Irving continues to monitor the State of Texas’ implementation of legislation requiring a study and report on seismic activity in our state.

During the most recent legislative session, Texas approved a $4.5 million allocation to the Bureau of Economic Geology (BEG) at the University of Texas at Austin to purchase equipment and produce a report on seismic activity by the end of 2016. The City of Irving’s efforts during the legislative session to increase the state’s efforts to monitor and report on seismic activity helped lead to the funding allocation. Irving officials continue to monitor the program’s progress.

As of the end of September, the Bureau had issued requests for quotes to purchase equipment and was advertising to fill technical and management positions to operate TexNet – the permanent network of seismic monitors – and to produce a report. The Bureau plans to have a permanent network of monitors installed later this calendar year and also will purchase sets of portable equipment that can be moved around the state as needed to monitor seismic hot spots should they occur.

Additionally, city officials continue to communicate with Southern Methodist University (SMU) seismologists who deployed 12 seismometers in our area last January. The scientists have been studying data collected since then.

SMU has conducted most of the seismic monitoring done to date in Irving and North Texas, and the BEG’s efforts would include using data SMU already has gathered, as well as including the SMU team in the broader study going forward.
Map: SMU preliminary earthquake catalog for the Irving/Dallas earthquake swarm from Jan. 1 to Oct. 16, 2015. Earthquake symbol size is scaled by local magnitude (magnitude 0.0 – 3.6) and color-coded by date of occurrence. Earthquakes with high location uncertainties have been removed. Seismographs currently recording earthquakes are shown as gray triangles. Note that additional seismographs are located outside of the map boundaries.

The map is provided as part of the ongoing collaboration between SMU and the cities of Dallas County through funding provided by the U.S. Geological Survey (USGS), SMU and City of Irving. Further information on the research collaboration can be found in the preliminary report on the earthquake sequence provided by SMU and the USGS to the mayors of Dallas and Irving in January 2015.

The SMU preliminary earthquake catalog has not been published in the peer-reviewed scientific literature and is subject to change; because the locations have not yet been approved for publication by the USGS, it does not represent any official USGS finding or policy.

Oct 2015 Earthquake Map
SMU analysis of recent earthquake sequence reveals geologic fault, epicenters in Irving and West Dallas

July 22 - Initial results from SMU’s seismology team reveal that the recent series of earthquakes occurring 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 (USGS) recently 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 Plano feel even smaller magnitude 2 earthquakes in the area.

The USGS initially mapped the earthquake locations as being spread out in a roughly circular area centered on the former 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 During January members of the SMU seismology team installed more than 20 seismographs in the affected area, including twelve 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 are already 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.