TRINIDAD, Colo. - A research team from the U.S. Geological Survey hopes to have a study published soon that may explain a recent series of minor earthquakes in the Las Animas County area around Trinidad.
The area had three earthquakes Wednesday and four more this month. The strongest was a magnitude 3.6 on the Richter scale. There have been no reports of injury or damage from the quakes.
Justin Rubinstein of the USGS said five of the quakes were at least a magnitude of 2.5.
"This level of (seismic activity) is not out of the ordinary for the Trinidad area," he said. "That said, the level was much lower than it is now."
Rubinstein said the average number of quakes above magnitude 3 in the area has risen since August 2001 from once biannually to eight annually.
"The majority of (activity) appears to be related to industrial activities in the area -- specifically, the deep injection of large volumes of wastewater from oil and gas fields -- appears to be making earthquakes more likely," he said.
Rubinstein said the study includes research of the area dating back to 1970. He said the primary research is already finished and awaits publication.
Residents of Trinidad and Las Animas County have mixed emotions about the earthquake trend. Many say they never notice the temblors and aren't concerned, while others wonder if the trend could result in bigger earthquakes.
The area had a magnitude 5.3 quake in August, 2011, that damaged several buildings. Experts say it was the state's largest natural quake in more than a century.
"The mortar in some of the downtown brick buildings is more than 100 years old," said resident Terry Sears. "Some of them shifted during the last strong quake. It wouldn't take one much stronger than that to bring down some of those buildings."
Kim Chavez, the county's emergency manager, said a disaster plan is in place to handle a major quake.
"I just worry if we're going to have a huge one, and we're not going to know how to react to it," she said. "We can have every emergency plan available, but it's when it actually plays out, to see if it's going to work."
Trinidad resident Michelle Finch said she believes she knows what to do if she experiences a major quake, such as though more common in California.
"I'm going to take action," she said. "Get out of the way, take care of my family, take cover, do what I can."