PLANETARY TREMORS: Magnitude 4.0 Earthquake Near Trinidad, Colorado - USGS! [MAPS + TECTONIC SUMMARY]

USGS earthquake location.

February 7, 2016 - COLORADO, UNITED STATES - The United States Geological Survey reported an earthquake with a magnitude of 4.0 near Trinidad Saturday afternoon.

The quake hit 26 miles west-southwest of Trinidad around 4:09 p.m., according to the USGS.

USGS shakemap intensity.

Time

1. 2016-02-06 23:09:10 (UTC)
2. 2016-02-06 18:09:10 (UTC-05:00) in your timezone
3. Times in other timezones

Nearby Cities

1. 42km (26mi) WSW of Trinidad, Colorado
2. 134km (83mi) SSW of Pueblo, Colorado
3. 142km (88mi) S of Pueblo West, Colorado
4. 152km (94mi) S of Canon City, Colorado
5. 177km (110mi) NNE of Santa Fe, New Mexico

- Denver Post.

Earthquakes in the Stable Continental Region

Natural Occurring Earthquake Activity
Most of North America east of the Rocky Mountains has infrequent earthquakes. Here and there earthquakes are more numerous, for example in the New Madrid seismic zone centered on southeastern Missouri, in the Charlevoix-Kamouraska seismic zone of eastern Quebec, in New England, in the New York - Philadelphia - Wilmington urban corridor, and elsewhere. However, most of the enormous region from the Rockies to the Atlantic can go years without an earthquake large enough to be felt, and several U.S. states have never reported a damaging earthquake.

Earthquakes east of the Rocky Mountains, although less frequent than in the West, are typically felt over a much broader region than earthquakes of similar magnitude in the west. East of the Rockies, an earthquake can be felt over an area more than ten times larger than a similar magnitude earthquake on the west coast. It would not be unusual for a magnitude 4.0 earthquake in eastern or central North America to be felt by a significant percentage of the population in many communities more than 100 km (60 mi) from its source. A magnitude 5.5 earthquake in eastern or central North America might be felt by much of the population out to more than 500 km (300 mi) from its source. Earthquakes east of the Rockies that are centered in populated areas and large enough to cause damage are, similarly, likely to cause damage out to greater distances than earthquakes of the same magnitude centered in western North America.

USGS seismic map.

Most earthquakes in North America east of the Rockies occur as faulting within bedrock, usually miles deep. Few earthquakes east of the Rockies, however, have been definitely linked to mapped geologic faults, in contrast to the situation at plate boundaries such as California's San Andreas fault system, where scientists can commonly use geologic evidence to identify a fault that has produced a large earthquake and that is likely to produce large future earthquakes. Scientists who study eastern and central North America earthquakes often work from the hypothesis that modern earthquakes occur as the result of slip on preexisting faults that were formed in earlier geologic eras and that have been reactivated under the current stress conditions. The bedrock of Eastern North America is, however, laced with faults that were active in earlier geologic eras, and few of these faults are known to have been active in the current geologic era. In most areas east of the Rockies, the likelihood of future damaging earthquakes is currently estimated from the frequencies and sizes of instrumentally recorded earthquakes or earthquakes documented in historical records.

USGS seismic hazard map.

Induced Seismicity
As is the case elsewhere in the world, 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. In much of eastern and central North America, the number of earthquakes suspected of having been induced is much smaller than the number of natural earthquakes, but in some regions, such as the south-central states of the U.S., a significant majority of recent earthquakes are thought by many seismologists to have been human-induced. 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. In addition, regions with frequent induced earthquakes may also be subject to damaging earthquakes that would have occurred independently of human activity. Making a strong scientific case for a causative link between a particular human activity and a particular sequence of earthquakes typically involves special studies devoted specifically to the question. Such investigations usually address the process by which the suspected triggering activity might have significantly altered stresses in the bedrock at the earthquake source, and they commonly address the ways in which the characteristics of the suspected human-triggered earthquakes differ from the characteristics of natural earthquakes in the region.

For More Information
Additional earthquake information for Colorado


- USGS.

PLANETARY TREMORS: Major Global Seismic Uptick As The Celestial Black Event Nears - EXTREMELY RARE 4.2 Magnitude Earthquake Strikes Michigan; Largest Tremor In The State Since 1947; Felt In Indiana, Ohio, Illinois, Wisconsin And Ontario! [MAPS + TECTONIC SUMMARY]

USGS earthquake location map.

May 2, 2015 - MICHIGAN, UNITED STATES - No injuries or damages were reported today after a magnitude 4.2 earthquake rattled Michigan and surrounding states shortly after noon today.

John Bellini, a geophysist at the U.S. Geological Survey's National Earthquake Information Center in Goldon, Colo., said the earthquake's epicenter was roughly five miles south of Galesburg, or nine miles southeast of Kalamazoo in central Michigan.

He said the earthquake at 12:23 p.m. could be felt widely across lower portions of the state and into northern Indiana, northwestern Ohio, eastern Illinois, southeastern Wisconsin, and western Ontario.

USGS earthquake location map.

Gov. Rick Snyder's office said there were no immediate reports of damages or injuries.

Bellini said Michigan has had only one other earthquake of this magnitude, a 4.6 earthquake that shook the state in August 1947. Its epicenter was close to Saturday's - about 30 miles to the southeast.

He said earthquakes of this magnitude are capable of causing minor damages, such as knocking items from shelves, cracking plaster or windows, or damaging brickwork or chimneys on older buildings.

He called today's earthquake "quite uncommon. Michigan doesn't get a lot of large earthquakes."

Since 1973, the state has had only two other recorded earthquakes - one in the western reaches of the Upper Peninsula, the other in central Michigan. He said dates for those quakes were not available.

He said he would not be surprised if Michigan has no aftershocks, or a few small ones that would not be felt.

USGS shakemap intensity.

Earthquakes tend to cause major damage beginning at a magnitude of 5.

"It is rare for Michigan to experience earthquakes," Snyder said in a statement, "but as we were reminded today, it does happen."

Snyder's office said Michigan State Police continues to monitor the situation.

Social media is buzzing with reports of the earthquake. Michigan residents reported feeling the earth shake in Grand Rapids, Lansing, Ann Arbor and Troy.

Residents report that they felt it last for a few seconds. Some say their house shook; others said it startled their pets. We've compiled some tweets of their accounts below.

- Detroit Free Press.

Tectonic Summary - Earthquakes in the Stable Continental Region

Natural Occurring Earthquake Activity

Most of North America east of the Rocky Mountains has infrequent earthquakes. Here and there earthquakes are more numerous, for example in the New Madrid seismic zone centered on southeastern Missouri, in the Charlevoix-Kamouraska seismic zone of eastern Quebec, in New England, in the New York - Philadelphia - Wilmington urban corridor, and elsewhere. However, most of the enormous region from the Rockies to the Atlantic can go years without an earthquake large enough to be felt, and several U.S. states have never reported a damaging earthquake.

Earthquakes east of the Rocky Mountains, although less frequent than in the West, are typically felt over a much broader region than earthquakes of similar magnitude in the west. East of the Rockies, an earthquake can be felt over an area more than ten times larger than a similar magnitude earthquake on the west coast. It would not be unusual for a magnitude 4.0 earthquake in eastern or central North America to be felt by a significant percentage of the population in many communities more than 100 km (60 mi) from its source. A magnitude 5.5 earthquake in eastern or central North America might be felt by much of the population out to more than 500 km (300 mi) from its source. Earthquakes east of the Rockies that are centered in populated areas and large enough to cause damage are, similarly, likely to cause damage out to greater distances than earthquakes of the same magnitude centered in western North America.

Most earthquakes in North America east of the Rockies occur as faulting within bedrock, usually miles deep. Few earthquakes east of the Rockies, however, have been definitely linked to mapped geologic faults, in contrast to the situation at plate boundaries such as California's San Andreas fault system, where scientists can commonly use geologic evidence to identify a fault that has produced a large earthquake and that is likely to produce large future earthquakes. Scientists who study eastern and central North America earthquakes often work from the hypothesis that modern earthquakes occur as the result of slip on preexisting faults that were formed in earlier geologic eras and that have been reactivated under the current stress conditions. The bedrock of Eastern North America is, however, laced with faults that were active in earlier geologic eras, and few of these faults are known to have been active in the current geologic era. In most areas east of the Rockies, the likelihood of future damaging earthquakes is currently estimated from the frequencies and sizes of instrumentally recorded earthquakes or earthquakes documented in historical records.

Induced Seismicity

As is the case elsewhere in the world, 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. In much of eastern and central North America, the number of earthquakes suspected of having been induced is much smaller than the number of natural earthquakes, but in some regions, such as the south-central states of the U.S., a significant majority of recent earthquakes are thought by many seismologists to have been human-induced. 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. In addition, regions with frequent induced earthquakes may also be subject to damaging earthquakes that would have occurred independently of human activity. Making a strong scientific case for a causative link between a particular human activity and a particular sequence of earthquakes typically involves special studies devoted specifically to the question. Such investigations usually address the process by which the suspected triggering activity might have significantly altered stresses in the bedrock at the earthquake source, and they commonly address the ways in which the characteristics of the suspected human-triggered earthquakes differ from the characteristics of natural earthquakes in the region.

For More Information

• Additional earthquake information for Michigan

- USGS.

PLANETARY TREMORS: 3.5 Magnitude Earthquake Strikes Athens County, Ohio - Highest-Magnitude Tremor In The Area Since 1886!

November 22, 2013 - UNITED STATES - Athens County shook Wednesday afternoon in a way it hasn’t since the 19th century.

A 3.5 magnitude earthquake, strong enough to be felt, with an epicenter slightly east of Nelsonville, was recorded at 1:01 p.m. Wednesday, according to the Ohio Department of Natural Resources.

USGS earthquake location.

The earthquake was the strongest to hit Athens since a quake of similar magnitude rocked the county in 1886, scientists said.

There were no reports of damage, though both ODNR and the Athens County Emergency Management Agency received dozens of calls about the quake.

"(Southeast Ohio) is not really a seismically active area," said Tim Leftwich, a seismologist at ODNR. "It's not noted to be an earthquake prone area of the state."

Calls from as far as Charleston, W.Va. were reporting shaking, Leftwich said.

Though the county is hundreds of miles from the nearest tectonic plate boundary — in the middle of the Atlantic Ocean — a small fault line runs through the northern part of Athens County, said Doug Green, a geophysicist at Ohio University who studies earthquakes.

USGS earthquake shakemap intensity.

“It’s consistent, the location of the earthquake (and) the approximate depth are consistent with a structural weak point in the Earth’s crust,” Green said.

The U.S. Geological Survey placed the quake’s depth at 7.9 km — too deep to be triggered by a fracking injection well, said Green, who is currently studying drilling’s effects on seismic activity.

An earthquake of magnitude 2.5 to 3 is the smallest earthquake generally felt by people, according to the Associated Press Stylebook, which also states a Magnitude 4 quake can cause moderate damage.

A helicorder sits in the Clippinger Laboratories to measure earthquakes as part of the Ohio Seismic network stations.

A 5.0 magnitude earthquake is the highest people in Ohio are likely to see, Green said. - The Post.

Tectonic Summary - Earthquakes in the Stable Continental Region

Image: The Post.

Most of North America east of the Rocky Mountains has infrequent earthquakes. Here and there earthquakes are more numerous, for example in the New Madrid seismic zone centered on southeastern Missouri, in the Charlevoix-Kamouraska seismic zone of eastern Quebec, in New England, in the New York - Philadelphia - Wilmington urban corridor, and elsewhere. However, most of the enormous region from the Rockies to the Atlantic can go years without an earthquake large enough to be felt, and several U.S. states have never reported a damaging earthquake. The earthquakes that do occur can strike anywhere at irregular intervals.

Earthquakes east of the Rocky Mountains, although less frequent than in the West, are typically felt over a much broader region. East of the Rockies, an earthquake can be felt over an area as much as ten times larger than a similar magnitude earthquake on the west coast. A magnitude 4.0 eastern U.S. earthquake typically can be felt at many places as far as 100 km (60 mi) from where it occurred, and it infrequently causes damage near its source. A magnitude 5.5 eastern U.S. earthquake usually can be felt as far as 500 km (300 mi) from where it occurred, and sometimes causes damage as far away as 40 km (25 mi).

Faults

Earthquakes everywhere occur on faults within bedrock, usually miles deep. Most of the region's bedrock was formed as several generations of mountains rose and were eroded down again over the last billion or so years.

At well-studied plate boundaries like the San Andreas fault system in California, often scientists can determine the specific fault that is responsible for an earthquake. In contrast, east of the Rocky Mountains this is rarely the case. All parts of this vast region are far from the nearest plate boundaries, which, for the U.S., are to the east in the center of the Atlantic Ocean, to the south in the Caribbean Sea, and to the west in California and offshore from Washington and Oregon. The region is laced with known faults but numerous smaller or deeply buried faults remain undetected. Even most of the known faults are poorly located at earthquake depths. Accordingly, few earthquakes east of the Rockies can be linked to named faults. It is difficult to determine if a known fault is still active and could slip and cause an earthquake. In most areas east of the Rockies, the best guide to earthquake hazards is the earthquakes themselves. - USGS.