Quake shakes Socorro, Magdalena

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It was felt not only on the third floor of a building at New Mexico Tech but also in Magdalena and Hop Canyon. An earthquake measuring 5.2 on the Richter Scale occurred at 9:52 p.m. Saturday near Duncan, Arizona, 160 miles away.

Two Socorrans reported to earthquake-report.com hanging plants, blinds and hanging lights began swaying. Another heard a loud boom. And another said her cats were acting strangely about five minutes before the tremblor.

The website received dozens of reports from Arizona and New Mexico, including:

• In Socorro: "I had just laid down in bed. I was still awake, and all of a sudden my bed rolled about four inches, then a couple seconds later it rolled back again. It felt like movement on a boat."

• Albuquerque: "I was in bed trying to sleep when I felt the bedroom shake for a few seconds. It was subtle, but I snapped awake and immediately thought 'earthquake.' I didn't find out until the next morning about (the earthquake) in eastern Arizona."

• Elephant Butte: "I was on the beach in an RV. It felt like someone rocked the RV back and forth for about five to seven seconds."

• T or C: "My whole trailer shook for about four to six seconds."

Shane Ingate, seismic lab associate in Tech's earth and environmental sciences department, said the tremblor was not connected with any fault line.

"It is a curious phenomena," Ingate said. "It was an intra-plate earthquake. In other words, in the middle of the plate. Not on a fault line."

But it's not all that uncommon. Socorro lies over the Rio Grande Rift.

"This is the most seismically-active area in New Mexico," Ingate said. "And the Socorro magma body is the most-studied geological feature of its kind in the world."

Quakes in the area are linked to a thin lens of molten rock – known as the Socorro Magma Body – situated 12 miles under the surface between Socorro and Belen area. The pancake shaped "blister" is slowly inflating and stressing the rocks above it, causing the ground above it to rise one to two millimeters a year.

This inflation, and rising, probably in association with shallow heated water, causes shallow earthquakes, generally in the 1.0 or 2.0 magnitude range.

Records at New Mexico Tech show that the Socorro region averages six earthquakes a year with a magnitude of 2.0.

The strongest recorded earthquake was in July 1906, measuring near 6.0 in magnitude.

The quake threw down several chimneys, knocked plaster from the walls of many adobe houses and the courthouse, and hurled shelf goods, book cases and dishes to the floor, according to the U.S. Geological Survey.

The entire business block, extending from the plaza along the north side of Manzanares Avenue, was damaged heavily. A two-story brick house, one of the buildings most severely damaged, was abandoned because its walls were cracked badly and thrown out of plumb. Nearby, one of the walls of another cottage was damaged so severely that the occupants moved outside to a tent. Many other residences sustained damage to walls and furniture.

Many boulders rolled onto the branch railroad leading to Magdalena, breaking one rail and many ties. Fissures formed in the ground near the Santa Fe railroad depot, and waves were seen on the ground surface.

That quake shook residents of Carthage, Kelly, Magdalena, San Antonio, San Marcial and other towns as far north as Albuquerque and as far south as Silver City. Tremors were felt daily, well into 1907.

Earthquakes during the summer of 1935 prompted many residents of Belen to spend their evenings sleeping outside out of fear that their houses would collapse, and three schools had to be closed in order to repair damage from falling plaster.

In early 1989, a flurry of 34 earthquakes with magnitudes between 2.0 and 4.7 occurred near the town of Bernardo.

More recently, a 3.5 magnitude quake shook the ground in northern Socorro County in 2004.

In September, 2007, a 3.5 earthquake shook the residents of Reserve.

In August 2009, a 2.6 magnitude earthquake was recorded in the Lemitar area.

The last was Feb. 28, 2013, registering 2.0 on the Richter scale, located 9.7 miles west of Socorro on Sedillo Plain, two miles northeast of Water Canyon Lodge.