Earthquake swarm strikes off West Coast again

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Experts say a “swarm” of small earthquakes off the northwest coast of Vancouver Island are part of the normal seismic activity in the area, and they could continue for several more days.

A 4.0 magnitude earthquake that struck just after midnight on Tuesday morning was the eighth small quake with a magnitude between 3.8 and 4.7 to strike the region since April 22.

Pacific Geoscience Centre Seismologist Gary Rogers said the activity is focused along a 20-kilometre stretch along an area called the Raveer Delwood Fault, located about 200 kilometres offshore.

“In the very thin crust that we have out there off our west coast of Vancouver Island, it often fractures in a series of small earthquakes, usually about this size being the maximum.”

Rogers said more small earthquakes are expected in the area over the next week.

“They often go on for days. There’s been a lot of smaller ones, so eventually they’ll wind down, but typically, what we’ve seen in the past is that most of these swarms last a few days to a week or so.”

A similar but more powerful swarm that struck the same area in August 2008 included a magnitude 5.2 quake.

Experts have been warning a major earthquake hits B.C. every 500 years, and the last one was in 1700. But they said the swarm of small earthquake activity does not indicate a larger earthquake is more likely in the short term.

The last significant quake to rattle the West Coast was a magnitude 6.5 tremor centered that struck about 50 kilometres off the west coast of the island in September of 2011, swaying high-rises as far away as Vancouver, Kelowna and Seattle.

 Discovery News > Earth News

MEDFORD, OR

Southern England and Wales were on high flood alert Tuesday, with thousands of homes at risk from a deluge that has killed one person after Britain’s wettest April in over 100 years.

Rivers were being closely monitored as flood defences held back muddy water from over 25,000 homes, the Environment Agency said. A total of 40 warnings of expected flooding and 152 alerts for possible floods were in place Tuesday.

“There is still a risk of flooding across many parts of England and Wales with particular focus on Somerset, Dorset and Devon,” the agency said Monday evening, ahead of a night of thunder and heavy showers.

Forecasters the Met Office said Tuesday that heavy rain was starting to ease but “there will still be a good deal of standing water and a continued risk of localised flooding since river levels remain high”.

Provisional Met Office data showed the past month has been the wettest April since records began in 1910. Figures to April 29 showed 121.8mm (4.8 inches) of rain fell on average, almost double the long-term average for April of 69.6mm.

A man and his dog were killed as they tried to cross a flooded ford in Hampshire, in southeast England, on Monday, while in Northamptonshire in central England, 1,000 holidaymakers were evacuated from a caravan park.

Despite the downpour, large parts of Britain remain officially in drought after two dry winters, with householders under instructions to save water where they can.

HASTINGS NE
DULUTH MN
DES MOINES IA
GRAND RAPIDS MI

GREEN BAY WI
GAYLORD MI
HASTINGS NE
OMAHA/VALLEY NEBRASKA

MOBILE AL
SAN JUAN PR

CLEVELAND OH
BOISE ID
SPOKANE, WA
INDIANAPOLIS IN
SPRINGFIELD MO
TULSA OK
NORMAN OK
WICHITA KS

Quake Charts Video: http://youtu.be/eP56Vf_lv40

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http://www.space.com/15474-supermoon-full-moon-2012.html
http://earthobservatory.nasa.gov/IOTD/view.php?id=77779
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature10967.html
http://www.reuters.com/article/2012/05/01/us-funds-pimco-idUSBRE8401C920120501
http://spaceweather.com/
http://rsd.gsfc.nasa.gov/goes/
http://www.haarp.alaska.edu/haarp/data.html
http://sdo.gsfc.nasa.gov/data/
http://umtof.umd.edu/pm/
http://sohodata.nascom.nasa.gov/cgi-bin/soho_movie_theater
http://www.ips.gov.au/HF_Systems/6/5
http://solarimg.org/artis/
http://www.swpc.noaa.gov/wsa-enlil/cme-based/
http://hisz.rsoe.hu/alertmap/index2.php
http://ccmc.gsfc.nasa.gov/cgi-bin/SWMF_RealTime_browse.cgi
http://grb.sonoma.edu/

A NASA space telescope has detected an incredible energy burst from a distant black hole, an explosion so intense that it boosted the black hole’s X-ray brightness by at least 3,000 times, scientists say. The outburst came from a black hole in the spiral galaxy M83, about 15 million light-years away from Earth. Using NASA’s Chandra X-ray Observatory, astronomers found a new object, called an ultraluminous X-ray source (ULX), that emits more X-rays than most “normal” systems in which a companion star orbits around a black hole or neutron star, the researchers said.

The observations from Chandra spanned several years, and scientists noticed that the ULX in M83 increased its X-ray brightness by at least 3,000 times.

This surprisingly sudden brightening is one of the largest changes in X-rays ever seen for this type of object, according to the researchers. In fact, ultraluminous X-ray sources do not typically have periods of dormancy. [Photos: Black Holes of the Universe]

In the accompanying image, the left is an optical view of M83. On the right is a composite image showing X-ray data from Chandra in pink and optical data from the Hubble Space Telescope in blue and yellow. The ULX is located near the bottom of the composite image.

Optical images of the black hole in M83 were taken by the European Southern Observatory’s Very Large Telescope in Chile. These images revealed a bright blue source where the ULX is located during the X-ray outburst. Yet, before the outburst, this blue source cannot be seen, the scientists said.

The discrepancy suggests that the companion to the black hole in M83 is a red giant star that is more than 50 million years old. The mass of this object is less than four times the mass of the sun, and according to theoretical models that predict the evolution of stars, the black hole in M83 should be almost as old as this companion red giant star.

The bright blue emission that could be seen during the X-ray outburst could be the black hole’s disk brightening significantly as it acquires more material from its companion star, the astronomers said.

Another strangely behaved ULX from a black hole with an old, companion red giant star was found recently in the galaxy M31. These new discoveries in M83 and M31 show that there could be a population of similar black holes that are older and more volatile, the researchers said.

The mass of the ULX in M83 is estimated to be between 40 to 100 times the mass of the sun.

The astronomers also found that the black hole in this system may have formed from a star surprisingly rich in “metals,” or elements that are heavier than helium. Based on previous observations, the ULX is located in a metal-rich region.

Large concentrations of metals increase the rate of mass lost from massive stars, siphoning mass before they collapse. This also decreases the mass of the resulting black hole.

Current theoretical models suggest that in regions highly rich in metals, only black holes with masses less than about 15 times that of the sun should form. As a result, the findings based on the ULX in M83 could dispute these models, the researchers said.

Another plausible explanation is that the black hole is so old that it formed at a time when heavy elements were much less abundant in M83, before metals were sprinkled throughout by later generations of supernovas. Astronomers are also investigating the possibility that the mass of the black hole in M83 is only about 15 times that of the sun.

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More than 32 Yangtze finless porpoises have been found dead in the Dongting and Poyang lakes in China in the last two months, leading wildlife experts to worry whether the rare animals are being pushed closer to extinction, the World Wildlife Fund has reported.

Yangtze finless porpoises live mainly in the freshwater Yangtze River and the two lakes, where the bodies of more than 32 of them have been found since March 3. One of the porpoises was pregnant, according to the blog Save Yangtze Finless Porpoise.

“This tragedy shows that Yangtze finless porpoise is facing enormous challenges,” said Lei Gang, head of WWF China’s Central Yangtze program, in a statement. “The porpoise deaths illustrate that without effective measures to fundamentally reverse the trend of ecological deterioration, [the] future of the incredible creature is far from certain.”

After examining the dead porpoises, scientists were left with a long list of possible culprits, including electro-fishing, strikes by boat-engine propellers, food shortages and pollution.

In electro-fishing, which is illegal, people use storage batteries to fire huge electric charges into the Yangtze and then collect the dead fish that float to the surface, according to an EDGE blog entry by Sam Turvey, who has studied wildlife along the Yangtze, including the Yangtze dolphin or baiji.

An autopsy report released April 17 by the Institute of Hydrobiology (IHB) under the Chinese Academy of Sciences suggests two of the finless porpoises were killed due to electro-fishing and boat-engine propellers.

Some experts have noted that climate change has lowered water levels in the Yangtze and its lakes, making it more difficult for porpoises to find food, but the researchers have yet to find any evidence that lack of food is resulting in porpoise deaths.

A 2006 IHB survey found about 1,800 Yangtze finless porpoises in the Yangtze River and connected lakes, but that number has been decreasing. From 2006 to 2010, the number of Yangtze finless porpoises in just the Dongting Lake decreased to 198.

Rather than relocate the porpoises, local government officials, along with cetacean experts with the WWF, are considering conservation measures in the Dongting Lake.

In addition, the local government plans to implement a ban on illegal fishing (including electro-fishing), regulate sand dredging and limit boat speeds, according to the WWF.