Volcanoes
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Bizarro Earth

Threat of pyroclastic flows from Mt. Sinabung still overshadows Karo residents

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© Volcano Alert @infoVolcano / TwitterLarge pyroclastic flow on Sinabung on 9 Oct 2014
It has been reported that Mount Sinabung in Karo regency in North Sumatra is still prone to emitting deadly pyroclastic flows that could occur at any time. During the past week, the active volcano repeatedly erupted, spewing hot clouds and showering the nearby city of Berastagi with volcanic ash.

Head of the Sinabung observation post, Armen Putra, said the pyroclastic flows were expected to continue as the volcano displayed intensifying activity. He said there was a good chance that Mt. Sinabung would keep erupting during the following days. "Based on our observations Mt. Sinabung is still emitting huge pyroclastic flows that could be discharged at any time in greater volumes than ever," he told The Jakarta Post on Sunday.

He said the pyroclastic flows currently travelled down the slopes to the south of several villages. On Oct. 5 they reached 4.5 kilometers to the south, which was deemed the longest descent so far. As of Sunday at 12 p.m., Mt. Sinabung emitted the hot flows on five occasions, reaching 3 km to the south.

"Residents living around the volcano should remain alert because the pyroclastic flows have been continuously released during recent days," Armen said.

Bizarro Earth

Mayon volcano's sustained reduction in sulfur dioxide emission, continuous surface inflation may lead to violent eruption

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Mayon volcano
A sustained reduction in sulfur dioxide emission and continuous surface inflation of Mayon Volcano may lead to a violent eruption, the Philippine Institute of Volcanology and Seismology (Phivolcs) warned yesterday. Phivolcs-Bicol chief volcanologist Ed Laguerta issued the warning after Mayon's gas emission dropped to 308 tons last Thursday, way below the normal 500 tons per day in the past 48-hour monitoring period.

He said the reduction in sulfur dioxide emission could mean that the lava dome protruding at the summit of the volcano is gradually blocking the crater. "If Mayon's crater is clogged by lava dome, a violent eruption is very likely to happen," Laguerta told The STAR.

He said they are closely monitoring Mayon's gas emission to determine if the drop would be a prelude to a small or big eruption. But Laguerta noted that even a phreatic or ash explosion may be followed by bigger eruption once the deep-seated magma deposit is depressurized.

He added that the absence of volcanic quakes in the past three days is not an indication that Mayon has calmed down.

Bizarro Earth

One wonders how many of these newly found thousands of volcanic seamounts are producing CO2 that bubble into the ocean

Scientists have created a new map of the world's seafloor, offering a more vivid picture of the structures that make up the deepest, least-explored parts of the ocean.

The feat was accomplished by accessing two untapped streams of satellite data.
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Thousands of previously uncharted mountains rising from the seafloor, called seamounts, have emerged through the map, along with new clues about the formation of the continents.

Combined with existing data and improved remote sensing instruments, the map, described today in the journal Science, gives scientists new tools to investigate ocean spreading centers and little-studied remote ocean basins.

Earthquakes were also mapped. In addition, the researchers discovered that seamounts and earthquakes are often linked. Most seamounts were once active volcanoes, and so are usually found near tectonically active plate boundaries, mid-ocean ridges and subducting zones.

The new map is twice as accurate as the previous version produced nearly 20 years ago, say the researchers, who are affiliated with California's Scripps Institution of Oceanography (SIO) and other institutions.

Comment: SOTT's been talking about methane outgassing for quite some time. Just a few results from a cursory search here on methane outgassing:

Arctic Ocean leaking methane faster than anticipated
Vast methane plumes discovered escaping from Arctic seafloor north of Siberia
New climate change threat: Arctic seabed releases millions of tons of methane into atmosphere


Bizarro Earth

Hawaii's Kīlauea Volcano alert level raised to Warning level

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© USGS

Current Volcano Alert Level: WARNING


Current Aviation Color Code: ORANGE

Volcanic Activity Summary: The June 27th flow remains active with a narrow flow moving about 30 m (100 ft) ahead of the previously stalled flow front and lava breakouts occurring from the lava tube about 8 km (5 mi) behind the flow front near where lava entered a crack system on August 18. The narrow flow front moved about 75 m/day (245 ft/day) since September 29, overtaking the stalled flow front during the past 24 hours. The leading edge is 2.3 km (1.4 miles) upslope from Apa'a St. and 3.3 km (2.1 mi) from Pāhoa Village Road, and approximately 16.4 km (10.2 miles) straight-line distance from the vent. Because this flow is moving very slowly and lava discharge from the vent remains low, we do not offer a projection of its future movement. Our next overflight is scheduled for Friday.

Pāhoa town is in the Puna District of the County of Hawai'i.

Recent Observations:
[Lava flow] A narrow flow has moved about 30 m (100 ft) past the stalled flow front in the past 24 hours. This flow has moved about 150 m (490 ft) since September 29.

Hazard Analysis:
[Lava flow] The June 27th lava flow from Pu'u 'Ō'ō vent is active with fresh lava being supplied to the flow front. The flow is slowly advancing downslope toward Pāhoa town.

Bizarro Earth

Volcanic eruption 1,200 years ago scattered ash from Alaska to Europe

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Microscopic image of a sample of White River Ash from the Yukon. The picture is of a polished surface of the pumice grains mounted in epoxy, which is how the samples are prepared for analysis.
A new study led by University of Alberta researchers has shown that a volcanic eruption 1,200 years ago scattered ash from Alaska to Europe - a discovery that will help researchers understand how future eruptions could affect the world.

Britta Jensen and Duane Froese in the U of A's Faculty of Science led the research, which showed that a distinct deposit of white, sand-sized grains of volcanic ash visible just below the modern forest floor over much of the Yukon and southern Alaska is present not only near the originating Mount Bona-Churchill in Alaska, but also in the Greenland Ice Sheet and across northwestern Europe.

The deposit, commonly known as the White River Ash, is so prominent that locals sometimes refer to it as "Sam McGee's Ashes" in reference to the Robert Service poem.

As part of the study, samples of the White River Ash, along with ash previously assumed to be from Iceland, were gathered from northern Canada, eastern North America, Greenland, Northern Ireland and Germany. By comparing characteristic features of these samples, the researchers showed that all of the ash originated from the same large prehistoric volcanic eruption in Alaska about 1,200 years ago.

Phoenix

Mount St. Helens shows signs of reawakening

Mt Saint Helens
© Susan Wyatt
Ten years ago this week, Mount St. Helens awoke from an 18-year geological slumber.

The news media and volcano-watchers flocked to Johnston Ridge, the closest road with a crater view. Steam and ash eruptions shot thousands of feet into the air, and for several weeks, the area near the volcano was closed because of safety concerns.

Over the next three years, a second lava dome slowly appeared in the crater, eventually rising 1,076 feet above the crater floor. By the time the eruption ended in 2008, climbers had already been allowed back to the summit and media attention faded.

Though the mountain isn't getting as much publicity these days, scientists with the U.S. Geological Survey are marking the anniversary to highlight new eruption warning technology they've installed around the volcano since then and to remind people that Mount St. Helens will continue to rebuilt itself.

The eruption that started a decade ago was the second of two dome-building phases.

The first one started after the explosive eruption of May 18, 1980. Twenty lava eruptions occurred over the next six years.

Geologists were surprised that the mountain stopped erupting in 1986. "Many of us were expecting it to continue a while," said USGS seismologist Seth Moran.

Bizarro Earth

Signs of activity surface at Mount St. Helens as 10th anniversary of last eruption nears

Mount St. Helens
© ThinkstockThe snow-capped crater of Mount St. Helens.
Ten years ago Wednesday, Mount St. Helens in Washington erupted after being quiet for nearly two decades, and now US Geological Survey (USGS) scientists are concerned that the volcano could mark the occasion by becoming active once again, various media outlets reported over the weekend.

The volcano reawakened in September 2004 and erupted on October 1, remaining active until late January 2008, according to the USGS. That event began with relatively small ejections of ash, which were followed by over three years of continuous slow lava extrusion - a stark contrast to the catastrophic May 1980 eruption that killed 57 and caused over $1 billion in damage.

"Since that time, scientists have been heavily monitoring the area to pinpoint when the next eruption will take place," said Tara West of Inquisitr News. Experts expect "future dome-building eruptions at the volcano," and while they are uncertain exactly when that could occur, Mount St. Helens is starting showing signs of activity, she added.

Cloud Lightning

More than 30 people believed dead at Japanese volcano

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© AP Photo/Koji UedaSeptember 28, 2014: A military helicopter, aiding in rescue operations, flies above Mount Ontake as it continues to erupt in Nagano prefecture. Military helicopters plucked several people from the Japanese mountainside Sunday after a spectacular volcanic eruption sent officials scrambling to reach many more injured and stranded on the mountain.
The bodies of more than 30 people believed to be dead have reportedly been discovered near the summit of an erupting volcano in central Japan.

A police official from Nagano prefecture told the Associated Press that the victims were not breathing and their hearts had stopped, which is the the customary way for Japanese authorities to describe a body until police doctors can examine it. The official added that the exact location where the bodies were found and the identities of the victims were not immediately known. He spoke on condition of anonymity because he wasn't authorized to speak publicly.

Bizarro Earth

The Geoscience behind the Mt. Ontake eruption

The eruption started at 11:53 am Saturday local time. A live webcam installed at Takigoshi captured a pyroclastic flow chasing down the south face of the volcano. Japan Broadcasting Corporation NHK released aerial video of the eruption available here, another video including people on a ridge with the glowering ash tower, and a different vantage point before aerial footage here:


Japan is at a triple-plate subduction boundary between the Eurasian continental plate and the Philippine and Pacific oceanic plates. As the denser oceanic plates dive below the low-density continental plate, water from the saturated sediments lowers the melting point of surrounding rock. That magma feeds a range of volcanoes mirroring the plate boundary.
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© Volcano World

Bizarro Earth

Update - Mammoth Lakes earthquakes now exceed 1059 in latest seismic swarm

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The Long Valley Caldera is experiencing a large seismic swarm. As magma moves through the earth, it displaces and fractures rock along the way. This movement causes earthquakes that can be recorded with seismometers at the surface of the earth. Seismic monitoring is the most used technique for volcano surveillance. Volcanic earthquakes often provide the initial sign of volcanic unrest. Their signals differ from typical, tectonic, earthquakes because they tend to be found at depths shallower than 10 km, are small in magnitude (< 3), occur in swarms, and are restricted to the area beneath a volcano. Harmonic tremor, or volcanic tremor, is the name for the continuous, rhythmic seismic energy associated with underground magma movement. At Long Valley Caldera, there are currently 61 seismometers that make up the seismic network used to determine earthquake location and energy of movement with time.
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The first instrument was installed in 1974 and additional instruments were added throughout the 1980s and 1990s. Between 2000 and 2003, the seismic network was updated to include additional, more modern instruments. More than 200 more earthquakes have erupted in the area in a 24 hour period. Additionally, some earthquakes were now reported at shallower depths. Rodger Wilson, who is following this area for tens of years, hasn't seen this activity since the 1990′s! We have the impression however that the frequency of the earthquakes has seriously declined the last couple of hours. The seismicity at Mammoth Lakes California has even increased compared to this morning. Below all earthquake epicenters during the last 24 hours. Depth of the hypocenters still at +10 km. Earthquake swarms are a regular phenomenon at Long Valley but nobody knows where the magma will move next. We will have to wait and see if this latest swarm indicates a massive movement of magma and might be an early-warning sign that Long Valley might be moving towards an eruption. The last eruption at the volcano is said to have occurred 700,000 years ago and is long over-due. - ER, USGS, TEP

Comment: Nearly 3 dozen small quakes in 24 hours - Volcanic unrest at Mammoth Lakes?