Earthquakes
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Better Earth

Geologists Map Birth Of New Ocean


MyFoxDFW.com
Mon, 03 Oct 2011 08:54 UTC
Image
© Unknown
A giant underground reservoir of molten rock has been discovered under the deserts of Ethiopia by British geologists, The (London) Sunday Times reported.

They targeted the Afar region in the Horn of Africa after a recent surge in volcanic activity and earthquakes plus the appearance of giant cracks in the rocky surface. Tectonic plates in the area are pulling apart and gradually creating a new ocean.

Now, the scientists have mapped the colossal underground lake of magma that lies up to 20 miles (32km) below the earth's surface.

"We estimate that there is 3,000 cubic kilometers of molten rock under Afar -- enough to cover all of London ... with around a kilometer of rock," said Kathy Whaler, professor of geophysics at Edinburgh University.

The reservoir is under such pressure that it has forced tongues of molten rock up towards the surface, producing eruptions and earthquakes.
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Bizarro Earth

Ohio, US: What's Underlying Cause of Recent Valley Quakes?

Karl Henkel
Vindy.com
Sat, 01 Oct 2011 12:11 UTC
Valley Quakes
© USGS
Thursday night's earthquake sent shock waves through most of Mahoning County.

The quake wasn't strong enough to create any damage, but it likely felt a lot stronger than a regular magnitude-2.5 rumble, said Michael Hansen, senior geologist at the Ohio Department of Natural Resources.

That's because rocks underneath the ground of river valley areas are mostly made up of unconsolidated sediments that amplify ground movement.

"That makes it feel higher intensity," Hansen said. That could explain the booming and crashing noises heard by some throughout the Valley. And although the initial magnitude registered a 2.5, Hansen said follow-up data could revise that number slightly higher.

"It may be 2.6 or a little bigger than 2.6, but not by much," he said.

Geologists have recorded earthquakes with epicenters in Mahoning County just six times - and all happened in the past 61/2 months.

All have occurred west of the Mahoning River, in close proximity to Salt Springs Road. The six earthquakes registered magnitudes ranging from 2.2 to 2.6. According to the Mercalli Intensity Scale, earthquakes between magnitudes 2.0 and 3.0 are felt by a few people, especially those on upper floors.

But why, after a lifetime with no earthquakes centered in Mahoning County, is the area averaging a quake per month?

Experts say there are a few reasons.
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Blackbox

Canada: Earthquakes could be linked to British Columbia gas drilling, says seismologist


CBC News
Thu, 29 Sep 2011 12:23 UTC
Image
© CBCGas wells like this one dot the landscape of northeastern B.C. in the pursuit of natural gas.
Seismologist says 'seismic swarm' should be investigated

B.C.'s energy regulator is investigating a cluster of earthquakes in a busy gas drilling area of the province, CBC News has learned.

Since 2009, more than 30 earthquakes have been registered in the Horn River area, a region that has also seen extensive drilling and a process called hydraulic fracturing used by companies extracting natural gas.

Hydraulic fracturing, also known as fracking, involves injecting a pressurized mix of water and other substances into the rock to release trapped natural gas. The B.C. Oil and Gas Commission said it has not identified a direct link between hydraulic fracturing and the seismic activity, but is examining recent data collected from Horn River.

The coincidence of earthquakes and gas exploration warrants further investigation, said University of Calgary seismologist David Eaton.

"This would fall within the descriptor of a seismic swarm," Eaton told CBC News. "I think, you know, any links to hydrocarbon extraction of fluid injection would be really interesting."
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Bizarro Earth

Chile: Earthquake Magnitude 5.6 - Offshore Bio-Bio


US Geological Survey
Wed, 28 Sep 2011 10:34 UTC
Image
© USGS
Date-Time:
Wednesday, September 28, 2011 at 22:40:13 UTC

Wednesday, September 28, 2011 at 06:40:13 PM at epicenter

Time of Earthquake in other Time Zones

Location:
37.963°S, 73.903°W

Depth:
12.9 km (8.0 miles)

Region:
OFFSHORE BIO-BIO, CHILE

Distances:
43 km (26 miles) SSW of Lebu, Bio-Bio, Chile

42 km (88 miles) NW of Temuco, Araucania, Chile

145 km (90 miles) SSW of Concepcion, Bio-Bio, Chile

580 km (360 miles) SSW of SANTIAGO, Region Metropolitana, Chile
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Bizarro Earth

Increasing Indications of a Potential Eruption at El Hierro?


Wired.com
Wed, 28 Sep 2011 08:13 UTC
El Hierro
© Wired.comPotentially young pahoehoe lava flows at El Hierro in the Canary Island.
We've been closely watching the earthquake swarm at the Canary Island's El Hierro since the middle of the summer and it looks like there has been a dramatic increase in the number and intensity of the seismicity at the volcano. Since mid-July, the small island, which is the top of a shield volcano built by the Canary Hotspot, has registered over 8,000 earthquakes - check out the excellent video of the changing depth and location of seismicity put together by Eruptions reader Lurking (or is it GeoLurking now?) Until recently, the earthquakes have not been noticeable to the people living on El Hierro, but since Monday, multiple ~M3-4 earthquakes have occurred, with 30 earthquakes alone on Monday*.

Interestingly, if you look at the distribution of the earthquakes (see below), the earthquakes over the last few days are deeper than those 4 days ago or older. Many are centered 14-16 km below the surface of the volcano, putting them into the upper mantle, the likely source of the magma in the Canary Hotspot plume. The increasing seismicity and intensity might suggest that an eruption is in the cards, but you would really expect the earthquakes should be getting shallower as magma nears the surface and right now, it doesn't appear to be the case. Maria Jose Blanco, director of the National Geographic Institute on the Canaries puts the chances of an eruption in the near future at ~10%, although carbon dioxide emissions are steadily rising (spanish), another clue on new magma degassing under the volcano.

Comment: For additional data see Canary Islands Government Raises El Hierro Volcanic Risk Level.

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Bizarro Earth

Greece: Earthquake Magnitude 5.1 - Crete


US Geological Survey
Tue, 27 Sep 2011 09:09 UTC
Image
© USGS
Date-Time:
Tuesday, September 27, 2011 at 12:08:21 UTC

Tuesday, September 27, 2011 at 03:08:21 PM at epicenter

Time of Earthquake in other Time Zones

Location:
34.413°N, 23.677°E

Depth:
19.1 km (11.9 miles)

Region:
CRETE, GREECE

Distances:
126 km (78 miles) SSW of Chania, Crete, Greece

167 km (103 miles) SW of Iraklion, Crete, Greece

259 km (160 miles) N of Tobruk (Tubruq), Libya

396 km (246 miles) S of ATHENS, Greece
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Bizarro Earth

Canary Islands Government Raises El Hierro Volcanic Risk Level

Mark Dunphy
Irish Weather Online
Mon, 26 Sep 2011 11:19 UTC
The Canary Islands Government has raised the alert level for the El Hierro volcano in the Canary Islands (Spain) to 'Yellow', the highest alert status since an unprecedented earthquake swarm commenced in mid-July.

Spanish seismologists, accompanied by the President of the Cabildo de El Hierro and the Minister of Security and Emergency Area, held a press conference on Sunday to reassure the 10,000 residents of the smallest of the Canary Islands that the raising of the alert level does not indicate that an eruption is imminent. They indicated, however, that the number of volcanic earthquakes detected beneath El Hierro continues to increase.

Image
© Google mapsEl Hierro (circled) in The Canary Islands.
Hierro, a shield volcano, has had a single historic eruption from the Volcan de Lomo Negro vent in 1793. The eruption lasted approximately one month and produced lava flows.

The Canary Islands Government commenced an in-depth geological survey of El Hierro earlier this month in an effort to determine the source of an earthquake swarm.
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Bizarro Earth

Rare Magnitude 5.3 Earthquake Hits Canada's Northwest Territories

Mark Dunphy
Irish Weather Online
Mon, 26 Sep 2011 10:52 UTC
A rare moderate earthquake struck the Northwest Territories region of Canada late on Sunday, the United States Geological Survey has confirmed.

Image
© Google mapsEpicentre of Sunday night's earthquake.
The 5.3 magnitude earthquake, the strongest recorded in the province this year, struck at 7:02:57 PM local time (2:02:57 AM GMT Monday). The epicentre was located 137 km (85 miles) W of Wrigley, 205 km (127 miles) S of Norman Wells, and 617 km (383 miles) WNW of the provincial capital Yellowknife.
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Evil Rays

Tennessee, US: Neighborhood terrified by mysterious shaking

John Treanor
Volunteer TV
Thu, 22 Sep 2011 16:31 UTC
Image
© Unknown
Adrienne Hooker doesn't feel safe at home. Her Blount County neighborhood has a problem - it shakes.

For 2 days, the house rocks every few hours. It can sound like an explosion.

She describes it like this: "Tiny earthquakes, makes the whole house shake it makes everyone wake up if they're sleeping."

They've called the U.S. Geological Survey, but no earthquakes have been reported.

They thought it might be construction at a nearby house, but the Blount County Sheriff's Office checked. Another dead end.

The "what" isn't all that important, they just want it to stop.
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Bizarro Earth

Tonga - Earthquake Magnitude 6.4


US Geological Survey
Thu, 22 Sep 2011 19:12 UTC
Tonga Quake_220911
© USGSEarthquake Location
Date-Time:
Thursday, September 22, 2011 at 23:07:03 UTC

Friday, September 23, 2011 at 12:07:03 PM at epicenter

Time of Earthquake in other Time Zones

Location:
15.449°S, 175.293°W

Depth:
8.6 km (5.3 miles)

Region:
TONGA

Distances:
174 km (108 miles) WNW of Hihifo, Tonga

256 km (159 miles) SSE of MATA'UTU, Ile Uvea, Wallis and Futuna

334 km (207 miles) ESE of Sigave, Ile Futuna, Wallis and Futuna

2569 km (1596 miles) NNE of Auckland, New Zealand
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