Lava From Space

[Buster's Uncle]

Sinking Iceland volcano crater raises flood worries
Reuters
15 minutes ago



Lava fountains are pictured at the site of a fissure eruption near Iceland's Bardarbunga volcano September 2, 2014. REUTERS/Armann Hoskuldsson



REYKJAVIK (Reuters) - Iceland's Bardarbunga volcano registered one of its most powerful earth tremors yet on Wednesday while the sinking of its caldera raised concerns of an eruption and flooding, authorities said.

The caldera, the cauldron-like crater at the top of a volcano, had sunk by up to around 20 meters since last week as magma channeled through underground passages moves away from the volcano, Magnus Tumi Gudmundsson, geophysics professor at the University of Iceland, told public service broadcaster RUV.

The caldera covers about 80 square km and is covered by an ice cap that is 700 to 800 meters thick.

A cloud of abrasive ash from the Eyjafjallajokull volcano, in a different region of Iceland, closed much of Europe's air space for six days in 2010, stranding tens of thousands of passengers, after an eruption under the ice cap.

"We take this increased subsidence in the caldera of Bardarbunga volcano very seriously, due to a possible large eruption and glacial flood," said Vidir Reynisson, Department Manager at Iceland's Civil Protection Department.

The ash warning level for aviation remained at orange, the second-highest level on a five-color scale, after several brief hikes to the top red in recent weeks.

Lava continued to pour from fissures in the ground, but there was still none of the ash that could prove troublesome for airline traffic. The 5.5 magnitude earthquake happened at 0528 GMT (01:28 a.m. EDT) near the volcano, Iceland's Meteorological Office said.

"This is one of strongest earthquakes since Aug. 16 (when tremors began). There is a lot of activity in the area and approximately 70 earthquakes have been measured in the night," said IMO geologist Sigurlaug Hjaltadottir.

Lava from cracks around Bardarbunga has so far entered the surface on ice-free land, whereas an eruption under an ice cap may be explosive and produce an ash cloud that could disrupt aviation, as well as flooding due to melting of the ice.

(Reporting by Robert Robertsson; writing by Sven Nordenstam)


http://news.yahoo.com/sinking-iceland-volcano-crater-raises-flood-worries-143811202.html

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Lava From Space
The Atlantic
By Robinson Meyer  27 minutes ago



Late last month, the Holuhraun lava field in central Iceland spasmed with earthquakes as lava began spewing from it once again. Now two weeks into its spurt of activity, its lava flow now stretches 10 miles long and covers eight square miles. It’s the island nation’s biggest volcanic event since the 19th century.

And you can see it from space.

Earlier this week, the U.S. government’s Earth-observing Landsat 8 satellite passed above Holuhraun and caught it in action. Landsat is the oldest continually operated program of its kind: Its satellites have been continually capturing images of the Earth since the Nixon administration.





Note that both of these images are false-color: They’re not exactly what you would see were you to peer out the window of the International Space Station and look down. The Landsat sensors read light from 11 different “bands” of the electromagnetic spectrum, and only five of those are visible to the unaided eye. Of its six other bands, three measure infrared light and two measure heat.

These images combine two infrared bands and the “green” band. This makes the incredible heat and energy of the lava flows visible, while also allowing us to see greenery and other common land features nearby.

But the lava flows even appear in “true-color” images. Here, for example, is the same image, but with only the visible bands:



NASA

The fire of the lava is still visible, though it’s not as vivid as in the infrared treatment. Zoomed out slightly, and the redness all but disappears—though the noxious smoke it emits remain huge across the landscape, a reminder of the wider consequences of any local disaster.



NASA


Read Lava From Space on theatlantic.com


http://news.yahoo.com/lava-space-184252681.html

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Iceland's erupting volcano looks absolutely stunning from space
Vox
Updated by Brad Plumer on September 10, 2014, 3:10 p.m. ET @bradplumer brad@vox.com



Since August 31, Iceland's Bárðarbunga volcanic system has been spitting lava out of a large fissure near the Holohraun lava fields in the middle of the country.

So far, the eruption hasn't inflicted much damage on people — but it has led to some spectacular photos and images. Here's a fantastic view from space, courtesy of NASA's Earth Observatory:



(NASA Earth Observatory)


Note that these aren't the same colors that the human eye would see from that distance. This image was captured by NASA's Landsat 8 satellite, which combined shortwave infrared, near infrared, and green light to create a false-color image. (If you want to see what the eruption looks like in "natural color," see here.)

And here's another shot zoomed out:



(NASA Earth Observatory)


Let's get oriented: The Bárðarbunga volcano itself is further to the southeast, out of the frame of this picture, buried underneath the Vatnajökull ice cap — the largest glacier in Europe.


This may be the biggest lava eruption Iceland has seen since the 19th century


Back in late August, scientists first began detecting seismic activity in the vicnity of the volcano, a sign that magma was on the move. That magma eventually formed a large underground dike that extended northeast, past the ice cap, where it eventually broke through to the surface. (The lava is now erupting out of two separate fissures.)

The resulting lava fountains have been spectacular, reaching more than 165 feet high, and the lava flow itself is 10 miles long — by some accounts, this is the biggest lava eruption from a single volcano that Iceland has seen since the 19th century.

Here's another close-up picture of the eruption from researcher Johanne Schmith:



(Johanne Schmith/University of Iceland)


So far, the eruption itself appears to be doing minimal damage, since it's in a remote area away from homes and villages. (Indeed, the ongoing eruption of Kilauea in Hawaii is wreaking more havoc.) The biggest problem to date is that a lot of sulfur-dioxide is spewing out of the volcano — a noxious gas that can cause respiratory problems.

NASA has more details on this: "A blue haze of SO2 and aerosols has been observed downwind over several towns and villages in eastern Iceland. Scientists and other observers working near the eruption site have been evacuated several times and cautioned to keep gas masks handy due to noxious gases and shifting winds. Elevated levels of SO2 have been detected as far as Ireland, Greenland, and Scandinavia.


Could Bárðarbunga have an even bigger eruption?

This is the key question right now. Earthquakes in the region have continued. And, most recently, scientists noted that the surface of the glacier atop of Bárðarbunga's caldera has begun to sink some 65 feet.


A subglacial eruption could send up large clouds of ash, disrupting flights


That could be a sign that the volcano is about to erupt under the glacier — and, given how much magma is in the volcano's chamber, any eruption could well be large.

That would be a big deal. If a really major volcanic eruption occurs underneath a glacier, the combination of magma and ice can potentially produce a violent steam explosion that can send large clouds of ash up into the atmosphere and disrupt flights around the region. Alternatively, a large eruption under a glacier can potentially melt the ice and lead to heavy flooding — particularly in the river that extends north toward more populated areas.

Still, nothing's for certain yet. The Icelandic Meteorological Office says that any of three different scenarios could occur:

1) The caldera could stop subsiding, seismic activity could cease, and the lava flows in Holuhraun could eventually decline. Eventually, things settle down.

2) Alternatively, the ongoing lava eruption in the Holuhraun fields could eventually extend back to the glacier. When the lava reaches the ice, it could lead to an ash-producing explosion and possible flooding.

3) The caldera continues sinking and there's a large eruption at the edge of the volcano. That, the IMO notes, "would melt large quantities of ice" — leading to major flooding.

Or perhaps something else entirely will occur. As Gisli Olafsson, who is providing indispensable updates on Twitter, notes, volcanoes are full of surprises: "No need to panic though about #Bardarbunga yet — nature has its way of showing us its potential and then let[ting] us wait decades."


Further reading:

As always, the Icelandic Met Office has the best updates of what's going on with Iceland's volcano.

Here's a longer breakdown of why even a big subglacial eruption today wouldn't necessarily be as disruptive as the 2010 Eyjafjallajökull eruption that shut down airports around Europe for six days.


http://www.vox.com/2014/9/10/6132115/icelands-erupting-volcano-looks-absolutely-stunning-from-space