Rare Earthquakes Hit Texas and Colorado

4.4 Magnitude Earthquake Hits Western Texas, Near Snyder

September 11, 2011

Fox News - A 4.4M earthquake Sunday morning shook the ground across Scurry County and parts of West Texas.

The USGS reports the quake was centered 11 miles northeast of Snyder and had a depth of 6.4 miles. Click here - to report to the USGS if you felt the quake. The website shows reports of residents feeling the shakes from Lubbock, San Angelo and Brownwood.

The USGS website offers these details on earthquakes across the stable continental region:

Most 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. The earthquakes that do occur strike anywhere at irregular intervals.

Earthquakes east of the Rocky Mountains, although less frequent than in the West, are typically felt over a much broader region. East of the Rockies, an earthquake can be felt over an area as much as ten times larger than a similar magnitude earthquake on the west coast. A magnitude 4.0 eastern U.S. earthquake typically can be felt at many places as far as 100 km (60 mi) from where it occurred, and it infrequently causes damage near its source. A magnitude 5.5 eastern U.S. earthquake usually can be felt as far as 500 km (300 mi) from where it occurred, and sometimes causes damage as far away as 40 km (25 mi).

Map of where this earthquake was felt:

Snyder's Increased Earthquake Activity May Be Due to Oil Drilling

March 15, 2011

KCBD - According to the United Geological Survey, Snyder, TX has recently had a dozen earthquakes ranging from 2.7 to 3.8 on the Richter scale. Researchers said they are looking into several reasons why there has been a spike in seismic activity in Scurry County in the last three years.

"These are small shocks that are either not felt or just very lightly felt," said Jim Dewey, a researcher for the U.S. Geological Survey.

Snyder is not an area prone to earthquakes, but in the last three years there have been fifteen. Sunday afternoon at 3:16 p.m. Scurry County residents were rattled by a quake and many reported feeling the rumble. The earthquake measured 3.8 and was located 16 miles northeast of Snyder.

Less than a week before that, a 3.2 and 2.5 quake struck close to the same area, seven miles east of the city.

"Earthquakes of 3.8 occur rather frequently in the central and eastern U.S. in a variety of situations," said Dewey.

Researchers from the U.S. Geological Survey said they are looking at a range of causes to explain the increase in Snyder-area earthquakes.

"The presumption is that they are related to either the extraction of oil or pumping fluid into wells for secondary oil recovery," said Dewey.

According to the U.S.G.S., another reason could be simple geology.

"This current activation could represent some activation of a very old fault, or it represents new fracturing of rock due to the change in the stress," said Dewey.

But the U.S.G.S. said this marked increase in earthquake activity only began in 2008. Before then, researchers reported no earthquakes near Snyder for the previous 20 years.

More than 30 years ago, in 1978, the U.S.G.S. reported a 5.3 quake jolting the area.

"That was strong enough to crack some windows and knock things from shelves. And that was felt up to a distance of 100 miles from the epicenter," said Dewey.

As researchers look for answers into what is causing these quakes on the South Plains, they will look to the past to predict the future.

"If they have been occurring intermittently over a year, they will likely keep going for a while. Then they may subside gradually," said Dewey.

The U.S.G.S predicts that in the next 50 years there is a 20 percent chance of a magnitude 5.0 or greater earthquake happening in the Snyder area.

Rare Strong Earthquake Hits Colorado

August 23, 2011

New York Times - The largest natural earthquake in Colorado in more than a century struck Monday night, August 22nd, in the state’s southeast corner, but there were no reports of damage or injuries.

The quake, with a preliminary magnitude of 5.3, was centered about nine miles from the city of Trinidad and hit at 11:46 p.m. local time. It was felt as far away as Greeley, about 350 miles north, and into Kansas and New Mexico, said Julie Dutton, a geophysicist at the National Earthquake Information Center in Golden, Colo.

Colorado, with its mix of mountains and plains, sits astride a seismically stable part of the nation where earthquakes are mostly mild and far between. But the area around Trinidad is regularly hit by tiny quakes as a result of a local fault zone, Ms. Dutton said.

She said that while Colorado had experienced several earthquakes close to Monday’s size in recent decades — a magnitude 5.3 near Denver in 1967 and a magnitude 5.7 in the state’s northwest corner in 1973 — both of those quakes were ultimately determined to have been caused by human activity, from explosives or drilling.

The last known natural event of comparable size was an earthquake in 1882 in what is now Rocky Mountain National Park. That quake, based on historical reports, was about a magnitude 6.5, Ms. Dutton said.

Flashback: Rare 4.0 Earthquake Hits South Texas April 2010

April 25, 2010

Eaxminer.com - A light to moderate quake jolted the South Texas area last night. The quake was some concern to the fact the area rarely sees this activity.

The quake was 28 miles West of Corpus Christi, TX and was a magnitude 4.0 on Sunday, April 25, 2010 at 02:10:41 UTC, which in local Texas time was around 11:10pm Saturday night.

Scientists are unsure at the moment what caused the quake in South Texas, however the earthquake density maps are very telling to the situation. The area does not experience these types of quakes.

The depth of this quake was around 5.0km, which suggests it was either geological or induced by oil production, which does happen. Never-the-less this is an interesting area to have a quake due to the fact the area has a large crack running north to south in Texas, discovered several years ago, origin being unknown.

The quake comes after a 4.3 Magnitude shaker in Mexico earlier in the day. All quake activity from the South Pacific to today's quakes in Mexico and the USA cannot be officially connected, nor confirmed to be.

Witnesses have reported items in their homes shuffled around and knocked photographs off the walls, but no major damage or injuries were reported.