TipsFocus.com

Several rare earthquakes gave some Texas people an early Halloween scare, shaking their beds and knocking pictures off walls but causing no damage or injuries, authorities said.

Irving resident Christine Laughland said she was sleeping when a quake woke her. She’s from California and knew what was happening. But she couldn’t say the same thing for her dogs.

“They were barking hysterically because it was their first one,” she said.

The first small shake came about 11:30 p.m. Thursday, rattling the ground in Irving, Grand Prairie and nearby communities. Several more quakes followed over the next 3 ½ hours, according to the Center for Earthquake Research and Information at the University of Memphis. At least two more were reported about 4 p.m. Friday in the same general area.

More small aftershocks are possible, experts said.

A 3.1-magnitude earthquake occurred Thursday about 11:30 a.m. near McLoud, Okla., a 5,000-resident town some 180 miles north of Dallas, with no reports of injuries or damage, according to the USGS.

But quakes in North Texas are puny. In fact, there is no geological evidence that this area has seen a strong quake in thousands of years, Dr. Ferguson said. And this week’s quakes are not necessarily evidence of more to come. If the area receives more quakes, people may not even feel them, he said.

Nobody knows exactly what causes a particular quake, Dr. Ferguson said. But it’s possible that the recent increased drilling and extraction of natural gas from the Barnett Shale had an effect. The extraction process affects the fluid pressure deep inside the earth, which is the sort of thing that could nudge a nearby fault, he said. It’s happened elsewhere.