This seems to lie within the Rio Grande Rift, a plate tectonic feature dividing the mountainous West from the more stable parts of eastern America. Clusters of earthquakes can precede a larger earthquake or indicate the motion of lava at depth perhaps leading to an eruption. In geological time the Rio Grande Rift has experienced both.
Revision: USGS has updated it down a notch, to magnitude 5.3.
OTOH, one of the 11 aftershocks so far was (from memory) revised up from a 3.X to a 4.1.
IANAG (...Not a Geologist), and kudos to cc101 for pointing out the Rio Grande Rift...but (from a few quick searches) this looks rather far east to really be part of that Rift. Though USGS's 30-day view shows ~30 more quakes, ~20 miles west of this one, and in a rough line pointing west toward the Rift. (Can a north-south rift do that? The Trans-Pecos Volcanic Field isn't all that far south of the 5.3, in the Davis Mountains - but it supposedly went dormant ~17mya. The USGS 'quake map shows no fault in the area...but they show very little of even the Meers fault, up in OK.)
Hopefully there won't be more/bigger 'quakes in that area. It's only 20 miles away from the Red Bluff Reservoir - which is held back by a ~90 year old, 100 foot tall earthen dam. Reservoir capacity is ~150K acre-feet; Pecos, Texas is ~50 miles downstream.
The quake occurred in an area of seismic activity associated with petroleum extraction. That looks like the most likely explanation. The lower part of the Rio Grande Rift broadens considerably.
I'm not familiar with the area, but the USGS shows 36 magnitude 2.5 or higher 'quakes along a ~50km long line in the past 30 days. Mostly at depths ~7km.
As natural disasters will rise in the US, I suggest all "traditionalist" (wooden wall loving) Americans to build their homes with concrete as Spaniards/Hispanics often did. They may not survive quakes but they are effective against hurricanes. And fires won't spread as easily.
Wooden structures are often excellent choices for earthquake country. They flex in an earthquake and often return to their original configuration.
Masonry, including concrete, is extremely vulnerable to earthquakes. Well engineered concrete structures can be safe but need extensive steel reinforcement. The steel may to be under tension in order to compress the concrete. A design by a qualified engineer is essential.
