I'm referring to the one that occurred a few days agodickg1 wrote:From the USGS, re: Oklahoma
The first earthquake known to have centered in the State occurred in September 1918. A series of shocks at El Reno produced only minor effects] April 9, 1952[/URL], earthquake centered near El Reno affected most of Oklahoma and parts of Arkansas, Iowa, Kansas, Missouri, Nebraska, and Texas. Damage from the 10:30 a.m. CST earthquake was not extensive, but many people in the epicentral area were alarmed, some to near panic. Portions of chimneys fell in El Reno and Ponca City (intensity VII). Bricks loosened from a building wall and tile facing of commercial buildings bulged at Oklahoma City. Also, plate glass windows were shattered in the business district of El Reno. The total damage amounted to several thousand dollars. Aftershocks were felt on April 11, 15, and 16, July 16, and August 14; an earthquake that was felt (IV) at Holdenville and Wewoka on October 7 apparently was unrelated to the April 9th event. Homes and buildings shook and some persons were awakened (V) at El Reno from the April 16th shock, which occurred 5 minutes after midnight. Felt reports were also received from Kingfisher, Oklahoma City, Tulsa, and Union City.
Minor damage to a building foundation and plaster (VI) at Concho resulted from two March 17, 1953, earthquakes about an hour apart. The felt area included Calumet, Edmond, El Reno, Minco, Okarche, Peidmont, and Union City.
On February 16, 1956, a shock at Edmond broke windows and cracked plaster (VI). It was also felt strongly at Guthrie, Oklahoma City, and Pawnee. Southeastern Oklahoma was disturbed by an earthquake on April 2, 1956, that produced thundering, rattling, and bumping noises that were heard by many citizens. Buildings shook and objects fell at Antlers, and many persons were alarmed (V). Minor effects were reported from other nearby towns. On October 30, 1956, an area of about 9,500 square kilometers in northeastern Oklahoma was shaken. The maximum intensity of VII was reported west of Catoosa, where a slippage of the formation caused an oil well to be shut down. Minor damage occurred at Beggs and Tulsa; and isolated felt report was received from Electra, Texas.
A broad area (approximately 31,000 square kilometers) of southwestern Oklahoma and the adjacent portion of Texas was affected by an early morning shock on June 17, 1959. Slight damage, consisting of cracks in plaster, pavement, and a house foundation (VI), occurred at Cache, Duncan, and Lawton. Houses were shaken, buildings swayed, and many persons were alarmed. A smaller earthquake on June 15 was felt by many at Ada and nearby places. Dishes were reported broken (V) and a trembling motion was observed.
On January 10, 1961, a mild shock was felt in Latimer and Pittsburgh Counties in southeastern Oklahoma. Thunderous earth sounds were heard in many places (V); no damage was reported. Another earthquake on April 27, 1961, awakened many (V) at Antlers, Coalgate, Hartshorne, Leflore, McCurtain, Panola, Poteau, Talihina, and Wilburton. Once again, thunderous, deep rumbling earth sounds were heard throughout the area.
An October 14, 1968, earthquake caused minor damage at Durant. Walls cracked, and glass in two structures broke (VI). The press reported that a 5 foot tall advertising stand fell over, and canned goods fell from a rack in a supermarket. Slight foreshocks were felt at Durant on October 10 and 11. Intensity IV effects from the October 14 shock were also noted at Caddo.
A magnitude 4.6 earthquake caused some cracked plaster (V) at Wewoka on May 2, 1969. Intensity V effects were reported at several other towns in the region. The total felt area included approximately 33,700 square kilometers in eastern Oklahoma.
Abridged from Earthquake Information Bulletin, Volume 8, Number 2, March - April 1976, by Carl A. von Hake.
For a list of earthquakes that have occurred since this article was written, use the Earthquake Search.
Questions:
Does the time frame cited above include any period of fracking - or were the incidents a natural phenomena? If natural, how are recent quakes attributed to fracking? What factual evidence exists that causes that attribution?
Dick
http://www.foxnews.com/us/2013/12/07/ma ... -oklahoma/
