Earthquakes
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Bizarro Earth

Increasing Indications of a Potential Eruption at El Hierro?

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.


Bizarro Earth

Greece: Earthquake Magnitude 5.1 - Crete

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

Bizarro Earth

Canary Islands Government Raises El Hierro Volcanic Risk Level

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.

Bizarro Earth

Rare Magnitude 5.3 Earthquake Hits Canada's Northwest Territories

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.

Evil Rays

Tennessee, US: Neighborhood terrified by mysterious shaking

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.

Bizarro Earth

Tonga - Earthquake Magnitude 6.4

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

Attention

Deadly Mudslides Hit Guatemala Day After Quake

Guatemala mudslide
© AP/Rodrigo AbdA man walks past a mudslide caused by an earthquake in Cuilapa, Guatemala, Monday, Sept. 19, 2011.
Mudslides in Guatemala killed one person and left 12 missing on Tuesday, a day after a series of earthquakes hit another region in the impoverished Central American nation, officials said.

The mudslides occurred near the small community of Santa Cruz Barillas, at an altitude of 1,500 meters (5,000 feet) near the Mexican border, some 400 kilometers (250 miles) north of the capital.

David de Leon, an emergency official, said four homes were swept away by the mud, with one person confirmed dead and 12 missing, in the latest incident provoked by heavy rains in the region.

Bizarro Earth

India: Sikkim quake unusual, say geologists

Image
© Unknown
Bangalore -- The earthquake that rocked Sikkim Sunday is unusual in terms of its magnitude and nature of origin, say leading geologists.

"There is nothing surprising in this earthquake as the region north of Sikkim, which forms the outliers of Tibetan tectonics, is known for moderate earthquakes in the past," C.P. Rajendran at the Indian Institute of Science here told IANS.

But what makes it different is its "unusually greater magnitude".

These earthquakes are different in the sense they are along the somewhat north-south structures trending transverse to the east-west Himalayan axis, Rajendran said. They are different from the usual Himalayan thrust earthquakes that are caused by the collision of the Indian plate with the Eurasian plate.

Bizarro Earth

US Alaska: Earthquake Magnitude 5.8 - Fox Islands, Aleutian Islands

Image
© USGS
Date-Time:
Monday, September 19, 2011 at 08:14:15 UTC

Sunday, September 18, 2011 at 11:14:15 PM at epicenter

Time of Earthquake in other Time Zones

Location:
52.041°N, 171.858°W

Depth:
34.7 km (21.6 miles)

Region:
FOX ISLANDS, ALEUTIAN ISLANDS, ALASKA

Distances:
65 km (40 miles) SW of Amukta Island, Alaska

104 km (64 miles) SW of Yunaska Island, Alaska

1678 km (1042 miles) WSW of Anchorage, Alaska

2430 km (1509 miles) W of WHITEHORSE, Yukon Territory, Canada

Bizarro Earth

5.8 Magnitude Earthquake Rocks Guatemala

Image
© USGS
A 5.8-magnitude earthquake shook Guatemala Monday around 12:30pm local time -- just a half hour after a 4.8-magnitude tremor struck near the same spot, according to the US Geological Survey (USGS).

The first quake struck at a depth of 37.9 miles (61km) just 25 miles (41km) southeast of Guatemala City.

The more powerful second quake hit at a depth of 24.5 miles (39.4km) and was located 33 miles (52km) southeast of the capital city, according to USGS data.