By Chris Sorensen

The first full week of November has been relatively seismically active in Colorado, with four earthquakes recorded within the state, and one just over the southern border in New Mexico.

The New Mexico quake, centered west of Raton, occurred late Saturday night and measured 3.1 on the Richter Scale. The area is about 90 miles south of Pueblo.

Three additional earthquakes occurred within seconds of each other in the early morning hours of Sunday and measured from 2.2 to 3.1. The quakes were originally reported as a single 3.1 event a few miles northeast of Greeley. Later information showed a 2.7 quake occurred first, followed five seconds later by the 3.1 quake, which occurred less than one-half mile further to the northeast. The final quake in the same are, about 45 seconds later, measured 2.2.

The most recent earthquake occurred Friday morning around 1:30 and was located about 10 miles north of Montrose in western Colorado. It measured 2.6 and occurred about a mile beneath the Earth’s surface. The remaining quakes were slightly deeper, occurring two to three miles below the surface.

Six earthquakes were recorded in Colorado in August this year.

According to the US Geological Survey, there is evidence that some central and eastern North America earthquakes have been triggered or caused by human activities that have altered the stress conditions in earth's crust sufficiently to induce faulting.

Activities that have induced felt earthquakes in some geologic environments have included impoundment of water behind dams, injection of fluid into the earth's crust, extraction of fluid or gas, and removal of rock in mining or quarrying operations.

Even within areas with many human-induced earthquakes, however, the activity that seems to induce seismicity at one location may be taking place at many other locations without inducing felt earthquakes.