|USGS earthquake location map|
January 6, 2015 - TEXAS, UNITED STATES - A lot of shaking going on Tuesday in the state of Texas.
As of 10:35 p.m. there have been seven earthquakes in Texas, five of those centered in or near the Irving area. The latest two earthquakes confirmed by the U.S. Geological Survey were near Farmers Branch and Irving — the first at 9:54 p.m. and the latter at 10:05 p.m.
The sixth earthquake, just before 10 p.m., had a magnitude of 1.7. The seventh earthquake, the fifth to hit Irving in one day, registered 2.4.
WATCH: Earthquakes rock Texas.
The shaking started early in the afternoon wit the first North Texas earthquake reported in Irving. The USGS later confirmed a second 3.5 magnitude quake near Snyder, about 230 miles west of Fort Worth. Then a third earthquake was confirmed near Irving again, just before 7 p.m.
A fourth and fifth earthquake hit North Texas around 8:15 p.m.
The fourth quake was a 2.9 magnitude and the fifth registered 2.7, according to the USGS. Both were smaller than the third, and strongest, Irving quake that registered 3.6. That happened at 6:52 p.m.
The second Irving quake was east of the first tremor, with the epicenter near the Elm Fork of the Trinity River.
Rafael Abreu, a geophysicist with the USGS, spoke with NewsRadio 1080 KRLD and said while the Irving earthquakes happened only hours apart, given the strength and intensity, “we’re not calling it an aftershock.”
|USGS shakemap intensity|
At last count Tuesday night, there had been 22 earthquakes in the Irving area since November 1, 2014.
The third earthquake is only the third in the DFW area, since 2008, to register 3.6 on the Richter Scale. The other two were in the Azle-area in November and December of 2013.
People from Dallas to Irving, and Grapevine to Plano reported feeling the first 3:10 p.m. earthquake. The USGS confirmed that a quake registered at 3.5 magnitude was centered east-northeast of Irving.
WATCH: January 6 Earthquake Inside Irving Apartment (Warning: Strong Language).
Physicist John Bellini with the USGS said earlier in the afternoon there should be little or no damage from quakes of this size.
USGS geophysicist Jana Pursley says Tuesday’s quakes were the “largest since the earthquakes started happening there in the last year.”
Several calls were also made to the Irving Police via 9-1-1 of people asking about the earthquake. - CBS Dallas.
Texas seismologists investigate quakes near old Cowboys stadium
|Texas Stadium is seen before the start of the last NFL football game to be played there in Irving, Texas December 20, 2008. REUTERS/Jessica Rinaldi)|
Seismologists installed a new earthquake-monitoring device in the Dallas suburb of Irving this week after a series of minor temblors rocked an area near the site of the former Dallas Cowboys football stadium.
Irving was hit by a magnitude 3.5 quake, the U.S. Geological Survey said. It was the strongest in a series of nearly 20 minor quakes to hit around Irving since September.
There were no immediate reports of injury or damage.
But the seismic series has left residents on edge, wondering if the situation will get worse and what has been behind an uptick in quakes over the last several years.
"The safety and security of our residents is paramount for the city of Irving," said Irving City Manager Chris Hillman.
Some residents believe the implosion of Texas Stadium in 2010 may have exacerbated problems. There is also speculation the quakes might be related to hydraulic fracturing, or "fracking," an energy extraction technique that has a long history in north Texas.
Irving, headquarters of Exxon Mobil's XTO unit that helped pioneer hydraulic fracturing in the region, has two gas wells that were fracked in 2010, according to city officials.
The study by seismologists from Southern Methodist University in Dallas is aimed at pinpointing the quakes' epicenters, said SMU seismology professor Brian Stump.
About 40 miles west of Irving, a series of small earthquakes rattled the town of Azle a year ago, causing sinkholes and cracks in house foundations. Residents blamed fracking and injection disposal wells for drilling waste as the cause but an official finding is still pending.
Energy industry officials have said fracking is safe and causes no significant seismic damage. - Yahoo.
Tectonic Summary - Earthquakes in the Stable Continental Region
Natural Occurring Earthquake ActivityMost of North America east of the Rocky Mountains has infrequent earthquakes. Here and there earthquakes are more numerous, for example in the New Madrid seismic zone centered on southeastern Missouri, in the Charlevoix-Kamouraska seismic zone of eastern Quebec, in New England, in the New York - Philadelphia - Wilmington urban corridor, and elsewhere. However, most of the enormous region from the Rockies to the Atlantic can go years without an earthquake large enough to be felt, and several U.S. states have never reported a damaging earthquake.
Earthquakes east of the Rocky Mountains, although less frequent than in the West, are typically felt over a much broader region than earthquakes of similar magnitude in the west. East of the Rockies, an earthquake can be felt over an area more than ten times larger than a similar magnitude earthquake on the west coast. It would not be unusual for a magnitude 4.0 earthquake in eastern or central North America to be felt by a significant percentage of the population in many communities more than 100 km (60 mi) from its source. A magnitude 5.5 earthquake in eastern or central North America might be felt by much of the population out to more than 500 km (300 mi) from its source. Earthquakes east of the Rockies that are centered in populated areas and large enough to cause damage are, similarly, likely to cause damage out to greater distances than earthquakes of the same magnitude centered in western North America.
Most earthquakes in North America east of the Rockies occur as faulting within bedrock, usually miles deep. Few earthquakes east of the Rockies, however, have been definitely linked to mapped geologic faults, in contrast to the situation at plate boundaries such as California's San Andreas fault system, where scientists can commonly use geologic evidence to identify a fault that has produced a large earthquake and that is likely to produce large future earthquakes. Scientists who study eastern and central North America earthquakes often work from the hypothesis that modern earthquakes occur as the result of slip on preexisting faults that were formed in earlier geologic eras and that have been reactivated under the current stress conditions. The bedrock of Eastern North America is, however, laced with faults that were active in earlier geologic eras, and few of these faults are known to have been active in the current geologic era. In most areas east of the Rockies, the likelihood of future damaging earthquakes is currently estimated from the frequencies and sizes of instrumentally recorded earthquakes or earthquakes documented in historical records.