Thursday, February 25, 2016

FIRE IN THE SKY: Twin Comets Approach Closely In March, As Celestial Events Increase - Flyby Will Be One Of The Closest In CENTURIES; One Of The Comets Will Be The THIRD-CLOSEST COMET To Earth In Recorded History!


February 25, 2016 - SPACE - A pair of comets showing very similar orbits are approaching Earth. While both will pass at a safe distance, one of them will have a record-breakingly close flyby.

Comet 252P/LINEAR 12 was already known to be passing by Earth on March 21, 2016 at a distance of 3,290,000 miles (5.3 million km).

This is about 14 times the Earth-Moon distance, and, taken by itself, sets no record.

But recently astronomers learned that this comet has company. On January 22, 2016, the Pan-STARRS observatory in Hawaii detected an object with a similar orbit that was preliminary designated as asteroid 2016 BA14.

Further observations showed a cometary tail, suggesting the object is a comet and not an asteroid.


The image on the left is a combination of five 300-s exposures tracking the 'asteroid,' while the image on the right is a smoothed version to help enhance the tail
(indicated by the arrow), proving that it is in fact a comet. (M. Kelley/S. Protopapa/UMD)

Did comet 252P split in two? We may find out soon.


Comet P/2016 BA14 (Pan-STARRS) will safely pass Earth on March 22,2016, passing even closer than comet 252P. Comet P/2016 BA14 flyby will be at just 2,199,933 miles (3.5 million km) or about 9 lunar distances, which is very close for a comet. In fact, this comet – P/2016 BA14 – will set a record as the third-closest known comet to pass our planet in recorded history.

Astronomers have seen a lot of asteroids coming even closer to Earth, but … comets are different. No, there is absolutely no danger to planet Earth, because 9 lunar distances is a very safe distance.

Which comet has passed closer to Earth than any other comet in recorded history?


Because it’ll be far from the sun, comet P/2016 BA14 will likely be very dim. But advanced amateur astronomers might still capture the celestial visitor. This illustration
shows the position of the comet shortly after sunset on March 22, 2016. Illustration by Eddie Irizarry using Stellarium.

First place goes to Comet D/1770 L1 (Lexell). Comet Lexell went at just 5.9 lunar distances on July, 1770. That was about 1,410,100 miles (2.3 million km), so close that Charles Messier noted the comet’s coma looked about the size of four times the apparent size of a full moon.

According to astronomers calculations, Comet 55P/1366 U1 (Temple-Tuttle) passed by Earth on October, 1366 at 8.9 lunar distances.

On May, 1983, comet C/1983 H1 ( IRAS-Araki-Alcock ) passed at 12.2 lunar distances. So comet IRAS – currently the third-closest comet to pass by Earth – will step down to become the fourth-closest after the upcoming flyby on March by the comet discovered this year (P/2016 BA14).

Since comet IRAS passed at 12.2 lunar distances, the upcoming flyby of P/2016 BA14 will be the closest flyby of a comet in 246 years!


Photo of comet P/2016 BA14 by Steven M. Tilley using the iTelescope.net Observatory in Siding Spring, Australia. Copyright Steven M. Tilley. Used with permission.


Will it be visible?

Comets may look bright when passing close to the sun. Although comet P/2016 BA14 will pass relatively close to our planet, its great distance to the sun will make it look very dim. It will not be visible to the unaided eye. If there are no variations in brightness, scientists estimate that Comet P/2016 BA14 should have a magnitude of 12 or 13 , which means it will only be captured with large telescopes. Good news is that we may have nice views coming from a famous telescope in orbit.

Astronomer Michael Kelly from the University of Maryland said:
We have secured 6 orbits of Hubble Space Telescope time to snap some high-resolution photos during the close approach.
The relative closeness of the comet to our planet will cause that images obtained by advanced amateurs and observatories will clearly show the motion of the celestial visitor, which is traveling at 31,345 miles per hour (50,445 km/h) through space.

Will this “new” comet produce meteors?

Probably not, but, according to some astronomers, there is a slight posssibility of seeing a few meteors related to Comet P/2016 BA14 around March 20, 2016. So heads up around that date, just in case.

The twin comets flyby will be a very interesting event. Stay tuned!

Bottom line: Two comets in similar orbits will pass Earth safely in late March. One of them – comet P/2016 BA14 – will set a record as the third-closest comet to Earth in recorded history. - Earth Sky.






EXTREME WEATHER: Powerful Storm System Kills 4 People In Virginia, Raising Death Toll To 8 - Knocking Out Power To Tens Of Thousands Of Homes And Businesses; 88 MILLION PEOPLE At Risk; Mass Flight Cancellations; Governor McAuliffe Declares STATE OF EMERGENCY! [PHOTOS + VIDEOS]

Destroyed trailers and vehicles are all that remain of the Sugar Hill RV Park after a suspected tornado hit in Convent, La., Tuesday, Feb. 23, 2016.(AP Photo/Max Becherer).
February 25, 2016 - VIRGINIA, UNITED STATES - A powerful storm system swept across the East Coast on Wednesday, killing four people in Virginia and knocking out power to tens of thousands of homes and businesses in the region. A girl in Michigan died following a three-vehicle crash on a snowy roadway.

A day earlier, the system spawned about two dozen tornadoes along the Gulf Coast, damaging hundreds of homes in Louisiana, Mississippi and Florida. Three people were killed and dozens were injured.

Forecasters had warned that more than 88 million people were at risk of seeing some sort of severe weather Wednesday. In the Midwest, heavy snow and biting winds led to mass flight cancellations at Chicago airports and school closings in several states.

In Virginia, Gov. Terry McAuliffe declared a state of emergency Wednesday evening. The tiny farming town of Waverly in the state's peanut-growing region took the brunt of the storm. The Virginia State Police said at least five structures were damaged in the town of approximately 2,000.

The names of the three people killed there were not released, but state police spokeswoman Corinne Geller said in a statement that they were a 2-year-old child and two men, ages 50 and 26. She said their bodies were found about 300 yards from their mobile home.

Roads leading into the town had to be closed because of downed trees and debris tossed by winds gusting to 60 mph, Geller said. A 7:30 p.m. curfew was imposed so search and rescue teams could go door to door checking on people.


Big this afternoon near Evergreen, Virginia. Wow! Photo by Jason Smith.
Twitter: Wouter van Bernebeek

Destroyed trailers and vehicles are all that remain of the Sugar Hill RV Park after a suspected tornado hit the park in Convent, La., Tuesday.(AP Photo/Max Becherer).

Damage from a tornado is seen Tuesday near Convent, La.(INCLUDING GREATER BATON ROUGE BUSINESS REPORT, 225, 10/12, INREGISTER, LBI CUSTOM).

A hardware store is destroyed near the intersection of Routes 70 and 1 Tuesday, Feb. 23, 2016, in Paincourtville, La.(Michael DeMocker/NOLA.com The Times-Picayune via AP)

People search a destroyed trailer at a business near the intersection of Routes 70 and 1 Tuesday, Feb. 23, 2016, in Paincourtville, La.(Michael DeMocker/NOLA.com The Times-Picayune via AP).


Witnesses said the storm swept through Waverly with little warning.

Timothy Williams said a friend had just come by to take his new car for a drive when the storm hit.

"It picked the car right off the ground, and put it right back on the ground," said Williams, 44. He said they remained in the car until the storm passed.
The storm blew down electrical wires "in a big ball of fire, thrashing all about each other," Williams said. He said they both escaped shaken but uninjured.

"I'm just a little nervous and jittery, but overall I'm OK," Williams said.

In Appomattox County, a funnel cloud left an 8- to 10-mile path of destruction, injuring seven people and killing one man, state police said.

At least 15 structures were destroyed and 25 injuries were reported when the storm passed through Essex County and the town of Tappahannock, about 45 miles northeast of Richmond, state police said. The injuries ranged from minor to serious, but were no confirmed fatalities.

In southern Michigan, a 6-year-old girl died following a three-vehicle crash. State police say Harlyn Radley died after the crash Wednesday afternoon near Battle Creek. Investigators say a car driven by the child's mother lost control and collided with another vehicle. A third vehicle then struck the wreckage. Police say speed and heavy, wet snow were factors in the crash.

On Tuesday, one of the hardest-hit areas along the Gulf Coast was a recreational vehicle park in the town of Convent, in southern Louisiana. RVs were tossed about and lay on top of wrecked cars and pickup trucks.


WATCH: Powerful storm hits Virginia.










Two people were killed there, and 31 injured people were taken to area hospitals, said St. James Parish Sheriff Willy Martin.

An all-night search of the RV park found no additional injuries or fatalities, the sheriff said. One person was still unaccounted for.

Briaxton Lott, 23, was in the trailer park when the tornado hit. The pad where his trailer once sat was empty and he pointed to the remnants of it about 100 feet away.

"The whole front end came up and slammed back down, and I grabbed up the baby and the next thing I know we just went rolling end over end," Lott said.

Bill Bunting with Storm Prediction Center estimated 20 to 24 tornados hit from Louisiana to Florida on Tuesday. Crews were still surveying so he couldn't be more specific.

The storms dumped several inches of rain in Alabama, Georgia and elsewhere, causing flash flood watches. Schools were closed in parts of Georgia, Florida and the Carolinas ahead of the storms.

In Mississippi, 73-year-old Dale Purvis died of blunt-force trauma in a mobile home west of Purvis, Lamar County Coroner Cody Creel said.

Florida Gov. Rick Scott said an apparent tornado in the Pensacola area significantly damaged more than 70 homes and 24 apartments, leaving three people with minor injuries.

He stopped at The Moorings apartment complex, where winds ripped the roof off of at least two buildings.

Residents in LaPlace, Louisiana, were cleaning up Wednesday after a tornado ripped up trees, tore roofs from houses and terrified local residents. Nearly 200 homes were damaged.

Rose Fuselier, 80, had a gaping hole where her home's front window once stood.

"The whole backyard is covered with trees, and then my shed is torn up, too. The roof is gone, and the siding is partially gone," she said. Still, she said others suffered damage even worse than hers: "I lucked out. I lucked out."

Becherer reported from Convent, Louisiana. Associated Press writers Rebecca Santana, in LaPlace, Louisiana; Melissa Nelson-Gabriel in Pensacola, Florida; Bill Fuller and Chevel Johnson in New Orleans; Freida Frisaro in Miami; Alanna Durkin Richer and Steve Szkotak in Richmond; Kasey Jones in Baltimore and Jeff Martin in Atlanta contributed to this report. - News Channel 10.








RATTLE & HUM: Mysterious Sounds Heard Across The Planet - West Island, Montreal Residents Captivated And Creeped Out By Trumpeting Sounds In The Sky?!


February 25, 2016 - MONTREAL, CANADA - Some West Island residents were captivated and creeped out by an eerie trumpeting sound that seemed to come from the sky Sunday. No one knows what caused the sound.

Early theories suggested people in Dollard des Ormeaux were hearing echoes of a Pointe-à-Callières Port Symphony. But those events happen at 2 p.m., and the sky trumpets were reported during the evening. Would sound have carried that far anyway? It's about 25 kilometres from the Old Port to D.D.O., and sound travels at Mach 1, so ... we don't know. Other atmospheric conditions would have to be factored in.

The Montreal Gazette asked a spokesperson at Environment Canada whether there any been any unusual meteorologic conditions Sunday night. "Not that we're aware of. There were no reports of anything in the Montreal area."

Witnesses to the sound say there was little to no wind at the time.

Montreal Gazette Facebook followers had a field day with the mystery. "Don't worry, Quebec will find a way to tax it," posted one reader. "Could they be clearing snow out there?" suggested a reader.

From another, what would seem to be the most obvious answer: "The wind does that sometimes, like with a pan flute." Then from the bottom of the earth: "We heard it here in Australia on Sunday. ... Birds went ballistic. Whether it's atmospheric radio waves or it is a warning, I know what side of the fence I would rather be on."

You can listen to the audio here.

- Montreal Gazette.






FIRE IN THE SKY: "Green Flash With Long Tail" - Fireball Reported Over Alaska!

File photo.

February 25, 2016 - ALASKA - Interior Alaska residents from Fort Yukon to Eielson Air Force Base reported seeing a fireball overhead Wednesday about 7 p.m.

The fireball, which was captured on the Geophysical Institute's All-Sky camera, flashed briefly into view and disappeared.

One resident described it as a green flash with a long tail. Others said the tail also contained orange and red fragments.

It was visible for only seconds, they told the American Meteor Society, which tracks sightings.

Don Hampton of the Geophysical Institute's Poker Flat Research Range said, "It looks like a good sized meteor, but probably not a meteorite (which means it hit the ground.)"

Link to video on Facebook.


- News Miner.







ANIMAL BEHAVIOR: Migratory Patterns And Disaster Precursors - Carcasses Of Olive Ridley Turtles Found Along Odisha's Puri Coast In India; Green Sea Turtles Hit By Cold Weather In Florida; Hundreds Of South Auckland Birds Killed By Botulism-Like Disease! [PHOTOS+VIDEO]

Dead and dying turtles

February 25, 2016 - EARTH - The following constitutes the latest reports of unusual and symbolic animal behavior, mass die-offs, beaching and stranding of mammals, and the appearance of rare creatures.

Carcasses of Olive Ridley turtles found along Odisha's Puri coast in India

Ahead of the mass nesting of Olive Ridley turtles, at least 40 turtles of the endangered species were found dead along the beach of Odisha's Pilgrim Town Puri.

Carcasses of the endangered turtles were spotted along the coast near Digabareni Khunti (Weather Pole) here yesterday.

Tourists and local people gathered at the site to witness the rare species of turtles which were lying bloated and decomposed. The forest officials buried the carcasses of the turtles to prevent it from being prayed on by predators like wild dogs, hyenas and jackals and minimise stench emanating from it.

Multiple injuries were found on the bodies of the turtles which points towards possibility of them being hit by fishing trawlers in the sea.

"We suspect that the turtles were killed after being hit by the fan blades of the fishing trawlers in the sea," a forest official said.

The dead turtles found along the coast in the holy town have raised concerns among the environmentalists and wildlife researchers as many whales were found dead on various beaches along the Odisha coast.

Notably, Olive Ridley turtles throng the Odisha coast for breeding and nesting during January-February. During this period, fishing activities are banned in 20 km distance from the beach to ensure the safety of the breeding turtles.

Earlier on February 17, over 150 dead turtles and a bottlenose dolphin was found near Mangala Nadi and Shri Vihar area in the city.

Besides, over 1000 dead turtles were spotted along the coast near Paradip under Gahirmatha marine sanctuary in Kendrapara district. - Odisha Sun Times.



Green sea turtles hit by cold weather in Florida

Clearwater Marine Aquarium (CMA) associate sea turtle biologist Brittany Workman listens to the heartbeat of a cold stunned green sea turtle while CMA senior turtle
biologist Cassie Seebart tucks another cold stunned green seat turtle in to a heated recovery area Monday, Jan. 25, 2016 in Clearwater, Fla.

© Jim Damaske/The Tampa Bay Times

Juvenile green sea turtles are washing up on local beaches — dead or in distress — at an alarming rate this year, experts say.

The Clearwater Marine Aquarium has picked up more than 129 dead and 93 living sea turtles since Feb. 3, more than the total number of dead specimens collected during all of 2015.

"We've already done a year's worth of work," said Adrienne Cardwell, the aquarium's manager of sea turtles and aquatic biology programs.

Crews have been responding to calls about the stranded young turtles and patrolling Pinellas County's northern beaches for the past two weeks, searching for the aquatic reptiles as water temperatures dropped — leaving many turtles with already compromised immune systems in trouble.

Because sea turtles need external heat to regulate their body temperature, cold water can cause decreased heart rate and circulation, lethargy, shock and even death.


WATCH: Update on Operation Cold Stun.




Many of the green sea turtles also contracted a virus in the wild called fibropapillomas, which can cause them to grow cauliflower-shaped tumors on their soft tissue and eyes.

Strong winds have pushed the weak, endangered sea turtles — some of which are unable to feed themselves — toward shore.

"These animals were already having issues, so the cold weather sealed the deal with them," Cardwell said.

Experts don't know how the virus, similar to the herpes virus in humans, is transmitted, and there is little conclusive research on the subject, Cardwell said.

The virus is becoming increasingly problematic among the local sea turtle population.

The cold weather mostly has affected turtles off Pinellas and Pasco county shores, where temperature drops have been more severe than in southern parts of Florida.

On Wednesday, Clearwater Marine Aquarium teams retrieved one dead and eight live sea turtles. Earlier this month, researchers picked up 22 dead and 13 live turtles in a single day.

The distressed animals are brought to the aquarium on Island Estates, along Clearwater's Memorial Causeway, where they are evaluated and treated with fluids and medicine.

Many of them don't make it through the first night, Cardwell said.

Some of the turtles recently recovered by Clearwater crews have been taken nearly 400 miles to a veterinary hospital in Marathon, in the Florida Keys, for rehabilitation and eventual release.

Cardwell said the aquarium is running out of resources to care for the distressed turtles and is seeking donations to help buy medical items such as gauze, rubbing alcohol and Rubbermaid bins to hold the turtles during their care.

Because of the influx, the aquarium has exhausted its sea turtle budget for this year.

Joe Widlansky, a sea turtle biologist with the nonprofit Sea Turtle Trackers, which monitors nesting on St. Pete Beach and Shell Key, said he has been dealing with similar problems along the coast in southern Pinellas County.

The juvenile green sea turtles he has found have weighed between four and 20 pounds. Last week he turned over two live turtles to the aquarium, but he also has found dead ones.

He recalled a significant statewide cold-stun in 2010 but expected the overall die-off to be lower this year because southern Florida largely has been unaffected.

"It's pretty bad. Hopefully it'll be over really soon with this nice weather warming up the water," Widlansky said. "We just hope every year by March it's over."

The green sea turtle primarily nests along Florida's east coast but can be found feeding on sea grass in shallow waters along the Gulf Coast.

Boaters and beach-goers should be on the lookout for stranded sea turtles or turtles floating on the surface of the water, Cardwell said. If they dive beneath the surface they likely are fine. - Orlando Sentinel.




Hundreds of South Auckland birds killed by botulism-like disease

The disease is mostly affecting waterfowl including ducks and gulls.© Anna-Marie Bakos

Hundreds of birds in a South Auckland wetland have been killed in a botulism outbreak.

The Department of Conservation and Fish and Game are working with the Pukorokoro Miranda Shorebird Centre to contain the outbreak.

The wetland is home to tens of thousands of rare native and non-native waterfowl and shore birds and it's estimated around 200 have died so far.

Fish and Game said it's an unfortunate thing to happen, especially in a significant wetland like Miranda.

"There is a botulism outbreak, which is a very serious bird disease. It is caused and spread by poor oxygen levels in the water - the birds ingest it and it's all over." said Don Rood, Fish and Game spokesman.

"It's not a nice way to go, it paralyses them then they die."

Rood said there's little that can be done, aside from burying the bodies, so the bacteria can't spread and re-enter the environment to infect healthy birds.

"What we're worried about is the deterioration of the general environment, when things like this happen there is a tendancy to down play it but anything that is killing birds in such a way is a concern." Rood said.

Department of Conservation Wildlife Vet Kate McInnes said this is a case of avian botulism and poses no risk to humans.

"It's triggered by environmental conditions which prompt a bacteria, found naturally in soil, to produce a toxin that cause birds to die."

McInnes said that botulism outbreaks usually clear naturally when rain and cooler temperatures change the conditions that triggered the outbreak.

The Miranda Shorebird Centre manager Keith Woodley said the outbreak of disease is concerning and has been killing waterfowl and shore birds over last two weeks.

"There is always concern when it's affecting our wildlife, but it's important to remember that outbreaks of this nature are not uncommon in this country, especially when conditions are warm and dry.

He added that the disease has so far only affected a small portion of the tens of thousands of birds in the wetland area.

Dead birds found at Pukorokoro Miranda have been sent to Massey University for testing to try and establish the cause of death. - Auckland Now.






WEATHER PHENOMENON: Breathtaking - Sea Of Clouds Cascading Over Mountain Like A Waterfall In China!


February 25, 2016 - CHINA - Nature lovers were given a treat when this sea of clouds rose majestically over a mountain before sliding down the side like a waterfall .

This breathtaking video shows the fast-moving clouds sweeping over the landscape as the sun rises on the horizon.

The stunning spectacle took place early on Wednesday morning over Mount Lu, in China's Jiangxi Province.

CCTV News reports that the incredible formation danced around the mountain top for several hours, attracting a large number of people with cameras.


WATCH: Beautiful sea of clouds in China.




Orographic clouds happen when air passing over a mountain rises and cools, until the vapour condenses into a formation and moves down the other side.

A similar phenomenon occurred last year in Iceland and was captured on a mobile phone in all its glory. - Daily Mirror.



DELUGE: Torrential Rainstorm Hit La Paz, Bolivia - Causes Flash Flooding Inundating Roads And Bridges; Red Alert Issued For The Ichilo River! [VIDEOS]

Bridge topped by the flash flood in La Paz, Bolivia. © Andrea Innocenti

February 25, 2016 - BOLIVIA - Intense rain and increasing river levels have been reported in Bolivia since 23 February, 2016. So far Bolivia's rainy season, under the influence of this year's strong El-Niño, has mostly been characterised by drought rather than floods.

La Paz


A torrential rainstorm hit the city of La Paz on the 24 February 2016, causing a flash flood resulting in the overflow of the Huayñajahuira River, a tributary of the Choqueyapu River. Starting at 17:00, intense rain affected the upper part of the urban watershed of Choqueyapu River, with no rain observed in the southern part of the city, where the flood occurred.

Video below courtesy of Andrea Innocenti:


WATCH: Flash flooding in Bolivia.






Several roads and bridges were quickly inundated in the Zona Sur, and the Costanera Avenue, the main road linking the city centre and the south district of La Paz, was closed causing issues to local transport.

Bermejo and Ichilo Rivers

On 23 February, 2016, the Municipal Emergency Centre for Operations (Centro de Operaciones de Emergencia Municipal - COE) of the city of Bermejo, in Tarija Department, declared a red alert for the increasing levels of the Bermejo River.

On the 24 February the National Service of Hydrology and Meteorology (Servicio Nacional de Meteorología e Hidrología de Bolivia, SENAMHI) issued a red alert for the increasing levels of the Ichilo River - a tributary of the Mamoré River - in Puerto Villaroel, Cochabamba Department. - Floodlist.





EXTREME WEATHER: Sydney Heatwave - City Sets Record For Days Above 26 Degrees Celsius As Mercury Hits 41.7C!

A father and daughter at Bondi beach. The Bureau of Meteoreology forecast temperatures of 41C in Parramatta, Penrith and Richmond, with 35C in the CBD.© Jenny Evans/AAP

February 25, 2016 - SYDNEY, AUSTRALIA - Sweltering day 21st consecutive day over 26C as Bureau of Meteorology predicts temperatures above 26C for the next week

Temperatures in parts of Sydney topped 40 degrees today, as the city sweated through a record streak of 21 days above 26C.

In Penrith, the temperature reached 41.7 by mid-afternoon and hovered just below into the evening.

Closer to the city it wasn't much cooler with 39.2C recorded at Sydney Olympic Park and 36.9 at the airport.

Blair Trewin of the Bureau of Meteorology told Guardian Australia the scorcher marked the 21st consecutive day of 26C or over in Sydney, a record stretch not matched at any time of year.

The next-longest streak was 19 days of temperatures above 26C in March 2014.

Trewin said the record hot spell was caused by a combination of warmer than normal ocean breezes, few major southerly winds and a lack of easterly troughs that tend to bring rain and cool temperatures. Since the streak started there has been just 9.2mm of rain in Sydney.

Sydney may continue its hot streak, with the bureau predicting temperatures above 26C for at least the next seven days. The coolest days will be on the weekend, with maximums of 27C forecast for both Saturday and Sunday.

Canberra is also feeling the heat with a maximum of 37C while Darwin and Brisbane are expecting maximums of 33C.

Trewin said: "It has been an unusually hot February in parts of the northern tropics because it's been much drier than usual for this time of year - it's normally the peak of the wet season."

The tropics were unlikely to set any records this month, though, as the hottest time of the year is usually in November/December before the wet season starts properly, he said. - The Guardian.






PLANETARY TREMORS: Oklahoma Earthquakes Stronger This Year - Count Slightly Less!

This image from EarthquakeTrack.com shows a cluster of small quakes in northwest Oklahoma in the past week. (Photo: Courtesy/EarthquakeTrack.com)

February 25, 2016 - OKLAHOMA, UNITED STATES - Since January 1 of 2016 until February 19 Oklahoma has recorded 339 earthquakes of magnitude 2.5 or greater.

Through the same period last year the state had recorded 389 quakes.

This year, seven earthquakes of 4.0 magnitude or greater have occurred in the state. Through the same time last year, four earthquakes of magnitude 4.0 occurred.

The strongest earthquake this year was a 5.1 that occurred February 13 in northern Oklahoma. - KOCO.



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.

- USGS.