Four Texas Quakes within 24 Hours

May 5, 2015 Elizabeth Alford

Another round of earthquakes hit north Texas this week, bringing the total number to 60 in the past year. The latest quakes were reported only two weeks after new evidence links fracking with increased seismic activity.

The United States Geological Survey is reporting a string of small earthquakes in Irving, a small community just northwest of Dallas. On May 3rd, two quakes measuring 3.2 and 2.5 magnitudes were registered about an hour apart and on May 4th, there were two more in the same area measuring 2.7 and 2.0 on the richter scale.

The USGS says that Irving and Northwest Dallas have experienced 60 quakes since April, 2014, but Brian Stump, a seismologist from SMU said that a more accurate picture reveals 388 seismic “events” so far this year in the area. The vast majority of these quakes are too small for people to feel, so they aren't making headlines. The quakes that have recently north Texas are small and cause minimal damage, but many wonder if all for this minor activity is a precursor to something more serious.

Before 2008, Texas earthquakes were rare, but have become much more commonplace.

“The sad thing is that this is happening so often I’ve started to recognize it immediately. The first time I felt a quake back in January, I walked around for a good fifteen minutes trying to figure out what had happened.”

— Dalles Morning News

Texas Earthquakes Linked to Fracking

April 22, 2015 Elizabeth Alford

A new study published Tuesday in the scientific journal, Nature Communications, confirms that oil and gas activities are likely to blame for a series of earthquakes in Azle and Reno Texas.

After a year-long investigation, researchers at SMU present findings that contradict the Texas Railroad Commission who have continued to deny the link between oil and gas operations and seismic activity.

Before 2008, Texas earthquakes were rare and both Azle and Reno experienced none. Since then, analysts have recorded over 150 significant quakes in North Texas including two magnitude 3.6 tremors in November and December of 2013.

“Regional geologic interpretations and historical accounts of regional seismicity independently suggest that natural tectonic stress changes represent an unlikely cause of the Azle earthquakes. The analysis therefore indicates subsurface stress changes associated with brine production and wastewater injection represents the most probable cause of recent earthquakes in the Azle area.”

Related: Texas Quakes Alarm Residents

Azle and Reno have not expereinced any more quakes since 2013, but other Texas locales aren't so lucky. A series of quakes rattled residents in the north Texas community of Irving in January ranging in intensity from a 2.6-3.7 on the richter scale.

Read full report at nature.com

Karnes County Earthquake Sets Record in Eagle Ford Area

October 21, 2011 R.T. Dukes

A 4.8 magnitude Karnes County earthquake rattled doors Thursday morning. (Atascosa County is now reported as the epicenter) You can view USGS data Here. It isn't the first earthquake in the area, but was larger than previous quakes. It was just 2008, which is before Eagle Ford Shale development began, when a 3.7 magnitude quake struck the area and 1993 when the largest I can remember hit the area (4.3 mag). Yesterday's disturbance is likely the largest on record for the area, but one of a dozen or so since 1990. Tremors were felt as far as San Antonio. Oil & gas drilling activity has not been linked to this event. If drilling directly led to earthquakes, West Texas would have fallen off the map a long time ago. It just so happens that oil & gas are present in areas of high tectonic activity. The Los Angeles basin is one of the most active areas in the world and also boast the most hydrocarbons per cubic ft of rock in the world.

There have been concerns that deep disposal wells where fluids are being injected into the ground could be tied to small earthquakes. It won't be clear for a long time if that might be the case here. Test are ongoing in more established shale plays in North Texas' Barnett Shale and in Arkansas' Fayetteville Shale.

No injuries or major damage was reported, and the light quake wasn't even noticed by some residents living close to the epicenter, near Karnes City. Yet small vibrations felt in San Antonio did cause occupants to briefly evacuate a downtown federal building as a precaution.
The quake struck at 7:24 a.m. The U.S. Geological Survey said it was the largest earthquake on record for the area, surpassing a magnitude-4.3 shock recorded in 1993.
Thursday's earthquake occurred in a zone that has shaken in the past. From 1990 to 2006, at least a dozen small quakes rattled this region.
"It's an area where we've seen events before," said U.S. Geological Survey seismologist Susan Hough in Pasadena, Calif. "So it's not a big surprise."

Read a full news release at nydailynews.com

Here's an interview with a geologist at ksat.com and an article from caller.com that details the total number of earthquakes expected worldwide this year.