https://twitter.com/Cmdr_Hadfield/status/313068610459430912/photo/1
https://twitter.com/Cmdr_Hadfield/status/313059132439662593/photo/1
https://twitter.com/Cmdr_Hadfield/status/313047734875734017/photo/1
https://twitter.com/teideano/status/313059716324532224/photo/1
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Sabancaya volcano (Peru): 400-500 earthquakes per day, increased degassing
Peru's Geological Mining and Metallurgical Institute INGEMMET and the Geophysical Institute of the National University of San Agustin Arequipa IGUNSA informed in a press release about the recently increased volcanic activity of Sabancaya:
From February 24 to March 6, 2013, the volcano's fumaroles produced a gas column rising 400 to 1000 meters above the crater. No ash emissions have been observed so far.
The report also mentions that since 28 Feb, there has been an average number of 400 to 500 earthquakes per day, mostly volcano-tectonic quakes related to rock fracturing in return probably related to intruding magma at depth.
The temperature of the hot spring La Calera has remained stable compared to previous years' values.
Ingemmet has set up an observation camp 12 kilometers from the volcano to conduct close visual, seismic, geodetic and chemical monitoring of the volcano ans report any significant changes.
http://www.volcanodiscovery.com/view_news/30842/Sabancaya-volcano-Peru-400-500-earthquakes-per-day-increased-degassing.html
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Earthquakes are not enough warning for some volcanic eruptions
15 March 2013, by Harriet Jarlett
It may not always be possible to predict volcanic eruptions through rising numbers of earthquakes, say scientists.
Fountaining volcano, Hawaii.
Using earthquakes to warn of eruptions well before they occur is necessary in case safety measures and evacuations need be put into place.
Before many eruptions the rising pressure of magma causes the ground to deform and fracture - resulting in earthquakes. So, changes in the number or pattern of seismic activity around a volcano can often be a signal that it could be about to erupt.
But scientists have now shown this might not always be the case, and using earthquakes alone to signal eruptions may not give us enough warning.
Previous studies had suggested that, on average, earthquake activity at Kilauea, a Hawaiian volcano, increased for around two weeks leading up to an eruption. But new research has found this trend is not as clear- cut as scientists first thought and earthquakes may only provide a clear warning for one type of eruption.
Dr Andrew Bell, from the University of Edinburgh, and Dr Chris Kilburn, from University College London, used data collected by the Hawaiian Volcano Observatory since 1959 to test this accepted trend against what they were actually seeing at Kilauea.
The study, published in the Bulletin of Volcanology, shows that increases in earthquake activity can occur at different times in the lead up to different types of eruption. Earthquake activity can increase several weeks before an eruption, but only before eruptions caused by the magma chamber becoming over pressurised.
But eruptions caused by rocks slipping on the volcano's flanks are also common, and these show an increase in earthquake activity merely hours before they occur. 'We've shown that increased earthquake activity at Kilauea is not enough on its own to predict an eruption in the short-term,' explains Bell.
'Where the earthquakes give a long warning period, it's more applicable to a wider volcanic setting, particularly volcanoes that have not erupted for long periods of time' continues Bell. 'At Kilauea the more common type of eruption has an extremely short warning period. But for a small subset of its eruptions it shows increased activity for a while leading up to an event. We can use this to help forecast eruptions at volcanoes we have less information for.'
Since more earthquakes often occur during periods of volcanic unrest, understanding how and where they occur can be crucial to predicting an eruption before it occurs. Being able to quantify the earthquake trends at Kilauea may help scientists to forecast eruptions at volcanoes with a more limited record of behaviour, like Mount Etna in Sicily.
Andrew Bell on Mt. Etna.
'Kilauea is an excellent place to study these pre-eruptive processes as there's a long history with multiple eruptions from 1959 to 1983. All of this data is recorded at the Hawaiian Volcano Observatory so it's a great resource,' Bell says.
Often the data set from other volcanoes is very small and there are very few well monitored eruptions. 'Using data from Kilauea as a way of seeing trends at these volcanoes is a bit of a trade-off. At Kilauea flank instability plays a bigger role than for other volcanoes, but we have a longer record to play with.'
Bell and Kilburn found that the previously reported trend was dependent on the quality of data – a key issue when dealing with any earthquake data catalogue that has been collected over a long period of time.
'Over time the sensitivity of equipment has improved and so in later years many more of the smaller earthquakes will be recorded compared to previous years. This means modelling trends is often extremely difficult as data quality changes,' explains Bell. 'Effectively in prior studies these data quality issues were not accounted for, and there was a degree of double counting data, so they saw an increase in seismic activity before eruptions even when there wasn't one.'
Although the direct implications for how volcanologists will be able to use this information to forecast other eruptions are still unclear, the team is now working on real time testing of forecast models during eruptions to see how well different factors predict these volcanic events.
Bell, AF and Kilburn, CRJ (2013) Trends in the aggregated rate of pre-eruptive volcano-tectonic seismicity at Kilauea volcano, Hawaii. Bulletin of Volcanology, 75 (1) 1 - 10
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Alaska's ever-sizzling Cleveland Volcano releases ash plume
Who needs TV in Alaska when you've got Mount Cleveland to watch? The ever-simmering volcano in the Aleutian Islands has once again let out an ash plume just one month after last being upgraded after satellite imagery indicated increased temperatures in the peak. NASA's Earth Observatory released a photo Friday showing a small ash cloud emanating from Cleveland and a field of ash staining the volcano's winter-white summit. The volcano rests on an unhabited island about 45 miles west of the community of Nikolski.
Cleveland had been listed under "advisory" status by the Alaska Volcano Observatory (AVO) on Wednesday, meaning that it was showing signs of unrest beyond normal background levels, but no imminent indications of eruption. Satellite imagery on a clear day Wednesday suggested no unusual activity at the volcano. In the most recent weekly report for Cleveland, observers said that temperatures in the dome had returned to normal in late February, prompting a downgrade from the "watch" status the volcano had been under.
"Anomalous surface temperatures prevalent in late January through mid-February declined, and the last thermal anomaly observed in satellite imagery was reported on February 26," researchers said, before downgrading the volcano to its current status.
Chris Waythomas, a geologist with the AVO, said that Thursday's ash burp was nothing alarming, or even out of the ordinary, for Cleveland.
"If you were to look at the summit of some other pretty constantly active volcanoes ... they'd look very similar," Waythomas said.
He said that the peak of Cleveland is typically pretty warm, and almost always snow-free, whether from the heat or from wind in the weather-weary Aleutians blowing across the summit. Cleveland has no real-time monitoring due to its remoteness, so scientists rely on distant seismic equipment and satellite imagery -- the latter of which is only really helpful on days when it's not cloudy.
"We've been keeping a pretty close eye on it -- or as close as we can -- and satellite data indicates the lava dome in the crater hasn't changed at all," Waythomas said. He said that the internal heat of the volcano can cause steam, and some ash to burst out of the peak on a regular basis, though it doesn't rise much beyond a couple of hundred feet.
Such activity is not classified as an eruptive event. The last real activity from Cleveland came in November of last year, when it spat an ash cloud to between 18,000 and 22,000 feet in a single event. It was downgraded again a little more than a week later. In the last year, Cleveland has seen numerous changes in status as it continues to gurgle on its remote island home.
http://www.alaskadispatch.com/article/20130315/alaskas-ever-sizzling-cleveland-volcano-releases-ash-plume--
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