|USGS earthquake location map.|
November 12, 2014 - KANSAS, UNITED STATES - A large earthquake that originated in Kansas was felt by residents across Oklahoma, Texas And Nebraska Wednesday afternoon.
The 4.8 magnitude temblor rumbled at 3:40 p.m., eight miles to the south of Conway Springs, Kansas, or about 124 miles north of the Oklahoma City metro, at a depth of three miles.
Several viewers called and wrote in, reporting to have felt the quake, some even as far south as Norman, Okla. So far there have been no reports of damage or injuries related to this earthquake.
According to the U.S. Geological Survey the quake was the same one felt as faraway as Irving and Dallas and Fort Worth. That’s not surprising, says John Bellini, a geophysicist with the USGS.
“It was also felt almost to the Nebraska border on the northern side,” he says, not to mention throughout Oklahoma and Kansas. Bellini says that nothing has been recorded in North Texas in the last hour.
But that Kansas quake, he says, “was a good-sized quake.”
Indeed: The USGS response chart, which continues to update, shows several reports from Dallas, Fort Worth, Allen, Irving, Denton, Wichita Falls and nearby Bellevue. Twitter also shows that some folks felt it Grand Prairie and Arlington.
|USGS earthquake shakemap.|
According to the United States Geological Survey (USGS), earthquakes with magnitudes ranging from 2.5 to 3.0 are generally the smallest ones felt by humans. Damage is more likely with earthquakes at magnitudes 4.0 and higher.
Earthquake activity in the area has greatly increased in recent years. The USGS said a likely factor in the dramatic rise in earthquakes in Oklahoma’s is wastewater injection, a byproduct of the oil and gas industry.
The southern part of Kansas has been experiencing an upsurge in earthquakes this year. A panel commissioned by Kansas Gov. Sam Brownback found there wasn't enough evidence to link the temblors to oil and gas exploration. The panel is recommending more study and the installation of more monitoring stations.
Forty earthquakes magnitude 2.5 or greater have rattled northern Oklahoma and southern Kansas in the last week, according to the USGS. Wednesday afternoon’s was by far the strongest.
- News9 | LA Times | AP | Dallas News.
Tectonic Summary - Earthquakes in the Stable Continental RegionNatural 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.
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. - USGS.
Kansas - Earthquake HistoryThe earliest, and possibly the strongest, shock reported within Kansas' borders occurred April 24, 1867. Several persons were injured, though not seriously. Plaster cracked, objects were thrown from shelves, and doors and windows were shaken at Lawrence. The earthquake was also felt strongly at Manhattan, where stones loosened on buildings and walls cracked. A heavy wave, about two feet high, was observed on the Kansas River at Manhattan. The tremor was felt over an area of 300,000 square miles in Kansas, Missouri, Nebraska, Arkansas, Illinois, Indiana, Kentucky, and possibly Ohio.
A moderate earthquake near Valley Falls, northeast of Topeka, on November 8, 1875, was felt over about 8,000 square miles in eastern Kansas and western Missouri. Dishes rattled; windows shook; some buildings rocked or quivered (intensity V).
Eastern Kansas felt the effects of a strong earthquake centered near Charleston, Missouri, in 1895. The October 31 shock affected about one million square miles over 23 States. Topeka reported the strongest effects in Kansas - houses shook and people were awakened. Dishes and windows rattled in other towns.
The area around Dodge City and Meade, in western Kansas, was shaken with an intensity V earthquake on October 27, 1904. Some reports indicated three shocks were felt at Dodge City.
On January 7, 1906, a strong shock affected an area of about 10,000 square miles in Kansas, Missouri, and Nebraska. Chimneys were thrown down and some cracks in walls were observed at Manhattan (intensity VII). Houses and buildings vibrated at Topeka, where a loud roaring sound was also heard. Some towns reported feeling two or three shocks. A series of small aftershocks of the January 7 earthquake was felt in Manhattan, the last being reported on January 23.
An earthquake on March 18, 1927, near White Cloud, in the extreme northeastern portion of the State, rocked houses such that people rushed out of them. The felt area was limited to about 300 square miles.
Four shocks - two on September 23, 1929, one each on October 21 and December 7, 1929 - were reported from the same area of northeastern Kansas. Houses shook over a broad area around Manhattan in September. The total affected area covered approximately 15,000 square miles. The October tremor was felt over an area of 8,000 square miles; that in December covered only 1,000 square miles. The maximum reported intensity of all these earthquakes was V.
A moderate earthquake was felt on February 20, 1933, over about 6,000 square miles in Norton and Decatur counties, Kansas, and Furnas and Harlan counties, Nebraska. Buildings and houses swayed; dishes and windows rattled; people ran out of their houses.
A damaging earthquake centered near El Reno, Oklahoma on April 9, 1952, affected a total area of 140,000 square miles, including all of the eastern half of Kansas. The magnitude 5.5 shock was felt in Kansas most strongly (intensity V) at Medicine Lodge; intensity V effects were also observed at Kansas City.
On January 6, 1956, minor damage occurred at Coats, Coldwater, Medicine Lodge, and Wilmore, Kansas, and Alva, Oklahoma. The damage was limited to loosened bricks, cracked plaster and chimneys, and objects knocked from walls and shelves. Many observers reported being shaken from their beds by the shock a few minutes before 6 a.m. The total felt area covered approximately 16,000 square miles.
Another felt earthquake with an epicenter in Kansas occurred April 13, 1961. The area affected was about the same as that from the 1933 tremor, principally Norton County, Kansas, and Furnas County, Nebraska. Intensity V was the maximum reported from this region.
The November 9, 1968, earthquake centered in southern Illinois was felt moderately throughout the eastern portion of Kansas. All or parts of 23 states were affected by this magnitude 5.3 shock. - USGS.