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Jocelle A

How fracking caused earthquakes in the UK - environment - 02 November 2011 - New Scientist - 2 views

www.newscientist.com/...sed-earthquakes-in-the-uk.html

Jocelle Amurao

shared by Jocelle A on 28 Aug 12 - No Cached
  • April and May this year, two small earthquakes struck the UK near the town of Blackpool.
  • hydraulic fracturing, known as fracking
  • controversial process to extract natural gas by fracturing the surrounding rock.
  • ...28 more annotations...
  • fracking caused the earthquakes.
  • magnitude-2.3 earthquake occurred on 1 April, followed by a magnitude-1.5 quake on 27 May.
  • Preese Hall drilling site
  • Cuadrilla Resources was using fracking to extract gas from a shale bed.
  • (BGS) suggested that the quakes were linked to Cuadrilla's fracking activities.
  • link with fracking has now been confirmed by an independent report commissioned by Cuadrilla, Geomechanical Study of Bowland Shale Seismicity
  • induced by direct injection of fluid into the fault zone."
  • two geologists
  • fracking could – and most likely did – provoke the quakes.
  • injecting huge volumes of water into the rocks surrounding a natural gas deposit
  • water fractures the rocks, creating dozens of cracks through which the gas can escape to the surface.
  • UK quakes were not caused by the violent rupturing of the rocks
  • water
  • lubricates the rocks and pushes them apart, allowing them to slip past each other
  • oiling the fault," says Brian Baptie of the BGS.
  • Fracking has been going on in the US for decades
  • become much more common in recent years
  • evidence
  • causes earthquakes
  • "This is one of the first times felt earthquakes have been associated with fracking," Baptie says.
  • Cuadrilla report says the earthquakes occurred because of a rare combination of circumstances
  • fault was already under stress
  • brittle enough to fracture and had space for large amounts of water that could lubricate it.
  • unlikely to happen again
  • small faults are probably common in deep rocks
  • given the same injection scheme in the same well, that there could be further earthquakes," he says.
  • If earthquakes begin to occur, it could reduce the flow of water into the well, or even pump it back out, preventing the bigger quakes.
  • damage
Annika H

Destroying five myths about earthquakes | The Japan Times Online - 1 views

www.japantimes.co.jp/...eo20110831a3.html

Annika

shared by Annika H on 28 Aug 12 - No Cached
  • 1. Animals sense impending earthquakes. A golden oldie. The notion that animals anticipate impending earthquakes predates the birth of Christ, with documented references to unusual animal behavior as early as the fourth century B.C. This belief was fueled recently by accounts, including one in The Washington Post, that some animals at the National Zoo had their knickers in a knot just before the 5.8 quake.
  • 1. Animals sense impending earthquakes.
  • This notion could contain a kernel of truth: Being generally squat, four-legged, close to the ground and inclined to sit still, an animal might feel an initial weak shaking that goes unnoticed by humans until stronger waves arrive. But also, it is an example of a natural human tendency to look back in time for anomalies, or precursors, that supposedly heralded the coming quake. Every pet owner understands that, say, cats and dogs sometimes behave strangely for no apparent reason; that's what cats and dogs do. And if an earthquake had not subsequently struck, you can bet we would not be talking about strange animal behavior this week — because we wouldn't have noticed anything out of the ordinary. As far as we understand, animals, like humans, have no ability to predict earthquakes.
  • ...10 more annotations...
  • 2. The frequency of large-scale earthquakes has spiked.
  • Yet the frequency of tremors across the world always fluctuates considerably from year to year. And the energy released by big earthquakes since the end of 2004 was less than the energy released by the two biggest recorded earthquakes: the 1960 temblor in Chile and the 1964 Good Friday quake in Alaska. The number of earthquakes greater than magnitude 7.0 has been somewhat high in recent years but well within the range throughout the 20th century.
  • Yet, as far as we understand, an aftershock of a certain magnitude is no different from an independent temblor of a similar magnitude. The shaking and rupture are the same; the energy released is the same. And aftershocks can be more damaging than larger "main shocks" if they strike closer to population centers. This lesson was illustrated with the earthquake that struck Christchurch, New Zealand, in February — an aftershock of a larger but less-damaging quake that occurred the previous September.
  • If enough stress has built up on a fault to generate a magnitude-7.0 earthquake, say, it would thus take about 1000 earthquakes with a magnitude of 5.0 to release the equivalent energy. The Earth doesn't work that way.
  • In any given area, the numbers of tremors of different magnitudes almost always follow a simple mathematical progression, with about 10 magnitude-6.0 quakes and about 100 magnitude-5.0 quakes for every single magnitude-7.0 quake. Thus, if there is significant strain energy to be released, it must be released in large earthquakes.
  • 4. "Don't worry, it was just an aftershock."
  • 3. Small earthquakes are helpful because they release pressure and prevent larger ones.
  • Recent studies show that any earthquake — even an aftershock — has the same small statistical chance of triggering a larger tremor. So a single quake can potentially be an aftershock and a foreshock, further clouding the differences among them.
  • 5. Earthquakes are a West Coast problem.
  • But, as millions of people on the East Coast were just reminded, less active does not mean inactive. By the end of the 19th century, two of the most notable temblors in the United States were the 1886 quake in Charleston, S.C., and a sequence of large events centered near the boot-heel along the New Madrid Fault of Missouri in 1811-1812.
Jocelle A

Access World News - Document Display - 1 views

infoweb.newsbank.com/...InfoWeb

Jocelle Amurao

shared by Jocelle A on 28 Aug 12 - No Cached
  • "Mars is at a primitive stage of plate tectonics
  • Earth may have looked and may help us understand how plate tectonics began on Earth
  • glimpse of how the early
annikam17

Weather Affects Timing Of Some Natural Hazards - Science News - 0 views

www.sciencenews.org/...timing_of_some_natural_hazards

Annika Marshall

shared by annikam17 on 28 Aug 12 - No Cached
  • Seasonal patterns of rainfall and snowfall can affect how often quakes and volcanoes go off, scientists reported December 8 at a meeting of the American Geophysical Union.
  • monsoon storms runs off the mountains
  • weight bends the Earth’s crust slightly
  • ...5 more annotations...
  • this bending causes the surface to move back and forth
  • Seismic records collected from 1998 to 2004 show that the number of quakes drops in the rainy summer months and rebounds when things dry out.
  • the flexing eases the stress on the fault where two tectonic plates collide beneath the Himalayas.
  • seismicity
  • Positioning System
Takeharu I

Access World News - Document Display - 0 views

infoweb.newsbank.com/...InfoWeb

Takeharu Imai

shared by Takeharu I on 28 Aug 12 - No Cached
  • Takeharu I on 28 Aug 12
     
    Jiji: Japan 's Deep Sea Drilling Vessel to Survey Quake Epicenter
Jonathan P

Scientist discovers plate tectonics on Mars - 1 views

www.sciencedaily.com/...120809155831.htm

shared by Jonathan P on 28 Aug 12 - No Cached
  • "Mars is at a primitive stage of plate tectonics. It gives us a glimpse of how the early Earth may have looked and may help us understand how plate tectonics began on Earth
  • Yin made the di
  • Yin made the di
  • ...2 more annotations...
  • covery during his analysis of satel
  • overy during his analysis of sat
Mizuho L

2010 Haiti quake possible start of new cycle of seismic activity - 0 views

www.sciencedaily.com/...120126152125.htm

shared by Mizuho L on 28 Aug 12 - No Cached
  • Mizuho L on 28 Aug 12
     
    "About"
Karen Jewett

Access World News - Document Display - 0 views

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Ms Jewett

shared by Karen Jewett on 28 Aug 12 - No Cached
  • Karen Jewett on 28 Aug 12
     
    "US braces for tsunami debris, but impact unclear"
Karen Jewett

Genetic engineering: a guide for kids by Tiki the Penguin - 0 views

tiki.oneworld.net/genetics

shared by Karen Jewett on 04 Apr 13 - No Cached
  • Karen Jewett on 04 Apr 13
     
    Genetically modified food
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