Via the Bad Astronomer, there is now a live video feed of the Eyjafjallajökull volcano in Iceland. It comes in two flavors: regular (visible) and infrared, so you can see a thermal version of the feed as well. It’s not an embeddable feed, so here’s the link. I’ve been watching it for awhile, and so far, there have always been people visible in the field of view, too. Scroll down on the page, and there’s also a map that shows the location of the camera relative to the volcano.
Above is the latest satellite imagery of Eyjafjallajökull, the Iceland volcano, taken on May 12, 2010, taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite. It shows the plume reaching a height of 4 to 5 kilometers (13,000-17,000 feet), even going above the clouds. The plume has switched directions from yesterday’s image, where the plume was blowing south and slightly southest; now it is blowing more easterly.
According to the Iceland Meteorological Office and the Institute of Earth Sciences at the University of Iceland, the eruption had changed little from previous days and showed no signs of stopping.
Iceland’s Eyjafjallajökull Volcano continues to spew out a thick plume of ash. Seen here on May 11, 2010, the ash was streaming almost directly south, visibly extending at least 860 kilometers (530 miles) from Eyjafjallajökull. According to the NASA’s Earth Observatory website and the London Volcanic Ash Advisory Center, the ash reached altitudes of 14,000 to 17,000 feet (4,300 to 5,200 meters). CNN reported that some Spanish and Moroccan airports were closed at the time. On May 10th, the Icelandic Met Office reported continuous ash fall south of the volcano, with as depths reaching 2-3 millimeters (roughly 0.1 inches). “Presently there are no indications that the eruption is about to end,” the Met Office said yesterday.
“By now ash has covered all surface snow and ice so the mountains looks quite different from the photographs what I mailed to you,” he said. “The eruption is affecting people in a small village southeast of Eyjafjallajokull, named Vik. There it is stopping normal life of people. They are leaving their homes and elementary school is forced to shut down, only because of the fine grained ash. But the people are not in a threat of anything serious like pyroclastic flow or poisoned gases.”
Gudmundsson said he would be venturing out for the next few days to try and take more images of the volcano, and will send us another update soon.
Here is another satellite image, of the Iceland volcano taken by Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite on May 10, 2010.
The volcano in Iceland keeps producing eye-popping effects. Now that the ash isn’t spewing quite so dramatically,the mouth of the volcano itself is visible. Here’s close-up aerial footage of the crater at Eyjafjallajokull, with glowing red lava and shockwaves of the eruptions in the ash cloud. Incredible.
Ever seen fire and smoke under water before? Oceanographers using a remotely operated underwater vehicle discovered and recorded the first video and still images of the deepest underwater volcano actively erupting molten lava on the seafloor. The ROV Jason vehicle captured the powerful event nearly 1.2 km (4,000 feet) below the surface of the Pacific Ocean, in the “Ring of Fire” region, near Fiji, Tonga and Samoa. “It was very exciting. We’ve never seen anything like that on the ocean floor,” said Bob Embley, a marine geologist with NOAA, who described the event an underwater Fourth of July. “When we started to see red flashes of light, everyone was extremely excited. Then we had to get down to the work of actually understanding of what we were seeing.”
The scientists presented their findings, along with HD video at the American Geophysical Union’s fall meetings in San Fransciso. The video was taken in May of 2009, and the science team said the undersea volcano is likely to still be erupting, and may have started activity in late 2008.
Embly said the eruption couldn’t be seen above the water, but there were “water column anomlies which indicated an eruption going on. We knew within a few hundred feet where the eruption was taking place.”
There were actually two erupting regions, but the video shows the most dramatic one. Visible in the video is magma – sometimes fiery, red hot at 1,371 C (2,500 degrees F) – bursting up through the seawater, with fragments of rock being propelled and magma flowing down the slope of the volcano. Hot sulfer “smoke” plumes can also be seen.
The volcano is spewing a type of lava known as Boninite, which until now had only been seen in extinct volcanoes more than a million years old.
A underwater “hydrophone” recorded the sound, and it was synched with the video.
Samples collected near the volcano showed the seawater to be highly acidic, similar to battery or stomach acid, the researchers said. Despite the harsh conditions, scientists found and photographed a species of shrimp apparently thriving near the volcanic vents.
“Nobody would have predicted that things would have survived long enough in water that acidic. It seems like it’s too harsh a condition,” said University of Washington chemical oceanographer Joseph Resing.
They hope to go back in a few months and see all the other creatures that have taken up residence there.
Geologists have identified 3 major types of volcanoes. There’s the shield volcano, formed from low viscosity lava that can flow long distances. There are cinder cone volcanoes, which are made by the eruption of lava, ash and rocks that build up around a volcanic vent. But the last type is the composite volcano, and these are some of the most famous volcanoes (and most dangerous) in the world.
A composite volcano is formed over hundreds of thousands of years through multiple eruptions. The eruptions build up the composite volcano, layer upon layer until it towers thousands of meters tall. Some layers might be formed from lava, while others might be ash, rock and pyroclastic flows. A composite volcano can also build up large quantities of thick magma, which blocks up inside the volcano, and causes it to detonate in a volcanic explosion.
Composite volcanoes are fed by a conduit system which taps into a reservoir of magma deep within the Earth. This magma can erupt out of several vents across the composite volcano’s flanks, or from a large central crater at the summit of the volcano.
Some of the most famous volcanoes in the world are composite volcanoes. And some of the most devastating eruptions in history came from them. For example, Mount St. Helens, Mount Pinatubo, and Krakatoa are just examples of composite volcanoes that have erupted. Famous landmarks like Mount Fuji in Japan, Mount Ranier in Washington State, and Mount Kilimanjaro in Africa are composite volcanoes that just haven’t erupted recently.
When large composite volcanoes explode, they can leave behind a collapsed region called a caldera. These are deep, steep-walled depressions which marked the location of the volcano. And it’s in this region that a new composite volcano will build back up again.
Another name for composite volcanoes are stratovolcanoes.
Remember that strange rock formation in Close Encounters of the Third Kind. It looked like the top of a toothpaste tube, but made of solid rock. That’s a volcanic neck, and it has nothing to do with space aliens. In reality, a volcanic neck is the solidified magma trapped inside a volcano. After millions of years, the softer outer layer of the volcano erodes, and all that remains is the volcanic neck. The structure in Close Encounters is Devil’s Tower, located in Wyoming.
Volcanic necks are somewhat rare because when a magma plug forms within a volcano, it often leads to an explosive eruption, like what happened with Krakatoa, or more recently with Mount St. Helens. The plug is broken up and ejected as ash and rock in a split second. But if the pressure isn’t great enough to actually detonate the top of the volcano, the plug cools and hardens deep within the Earth.
There are some very famous volcanic necks around the world. Probably the most famous is Devils Tower in Wyoming. It rises 386 meters above the surrounding landscape, a lone prominence of rusty red rock. I’ve actually stood beside it, and it’s one of the most impressive geologic features I’ve ever seen.
The type of erosion will define the shape of the volcanic neck. For example, glaciers will erode away one side of the volcanic neck, but leave a long tail behind.
Barcena is a volcano located on the island of San Benedicto, the third largest island of the Revillagigedo Islands. The whole island is only about 4.8 km by 2.4 km and Barcena takes up a good chunk of the southern end. Barcena rises to an elevation of 332 meters, forming a volcanic crater.
There has only been on eruption from Barcena in recorded history, but it was a big one. On August 1, 1952, Barcena had a severe Vulcanian eruption measuring 3 on the Volcanic Explosivity Index. It released huge pyroclastic flows that rolled over the entire island, covering it in ash and pumice to a depth of 3 meters. Within less than 2 weeks, it had created a new volcanic cone more than 300 meters high. A second series of eruptions started up later in the year, releasing magma that broke out of the cone and flowed into the ocean. By late 1953, the volcano went dormant again.
The eruption wiped out all the plants and wildlife on the island, making the San Benedicto Rock Wren extinct. Within a few years the plants and wildlife made a return, although the island still looks barren.
We have written many article about volcanoes for Universe Today. Here’s an article about Tacana, a tall stratovolcano that straddles the border between Mexico and Guatemala. And here’s an article about Paricutin, a volcano that suddenly appeared in a farmer’s cornfield.
Geologists classify volcanoes into three distinct groups: dormant, extinct and active volcanoes. Dormant volcanoes haven’t erupted in a long time, but they could again; extinct volcanoes have erupted for thousands of years and might be dead. Active volcanoes, on the other hand, erupted recently, and they’re probably going to erupt again soon.
There are approximately 500 active volcanoes in the world today, not including those underneath the oceans. In fact, as you read these words, there are probably 20 volcanoes erupting right now. Between 50-70 volcanoes are erupting every year, 160 have erupted in the last decade. And there are about 550 that have erupted since the beginning of recorded history.
The definition of an active volcano is difficult to pin down, since single volcanoes can have networks of volcanic vents across their flanks. And Iceland, there can be eruptions along volcanic fields hundreds of kilometers long. At Mexico’s Michoacan-Guanajuanto field, there are 1,400 cinder cones, maars and shield volcanoes coming from a single magma chamber.
And these are just the volcanoes on land. Scientists estimate that 3/4 of the lava that reaches the Earth’s surface happens underwater at the submarine midocean ridges.
So when does a volcano become dormant or extinct? A volcano is active if it’s currently erupting or showing signs of unrest. The Smithsonian Global Volcanism Program defines an active volcano as having erupted within the last 10,000 years. A volcano finally goes extinct when there’s no lava supply in the magma chamber beneath the volcano.
There are several different kinds of lava, depending on the chemical composition and temperature of the molten rock that erupts from a volcano. The smooth variety is called pahoehoe, and the rougher variety is known as a’a (pronounced ah-ah). A’a is a Hawaiian word meaning “stony with rough lava”.
If you’ve ever been to the Big Island of Hawaii and gone for a hike, you’ve seen a’a lava. It’s incredibly rough and jagged black rock that takes forever to walk across; and tears your shoes apart as you go.
During an eruption, a’a lava comes out of the volcano as a very thick (viscous) lava that travels very slowly. The inside of an a’a lava flow is thick and dense. Surrounding this thick dense core is a sharp spiny surface of cooling rock. These fragments of rock are carried on the top of the a’a lava flow and make a crunching grinding sound as the lava flows downhill.
Once the lava flow stops, it can take weeks or even years for the lava to harden completely. The interior dense core hardens in place with the jagged fragments surrounding it. This is why old a’a flows are so sharp and jagged.
A’a flows move slowly – you could easily outrun one – but they move fast enough to tear down buildings, cover roads, and destroy vegetation.
The smoother pahoehoe lava can turn into a’a lava as it gets further downhill. This happens because of the delicate balance of gas content in the lava, the changes in lava viscosity, and the rate of deformation as the lava flows and cools. Once this balance changes, the pahoehoe can change into a’a. Of course, a’a lava never changes back into pahoehoe.
Picture a volcano in your mind. You’re probably thinking of a cinder cone volcano, the simplest type of volcano. Cinder cone volcanos have steep sides with a bowl-shaped crater at the top.
Cinder cone volcanoes grow from a single vent in the Earth’s crust. Gas-charged lava is blown violently out of the volcano’s central vent, and the ash and rocks rain down around the vent. After multiple eruptions, the volcano takes on the familiar cone shape, with the erupted rubble forming the steep slopes. Cinder cones rarely grow much taller than 300 meters above their surroundings, and they’re common in western North America, and wherever there’s volcanic activity.
Although they can be solitary structures, cinder cones are often associated with other kinds of volcanoes, like shield volcanoes and stratovolcanoes (or a composite volcano). For example, geologists have discovered more than 100 cinder cones on the sides of Hawaii’s Mauna Kea, one of the biggest volcano in the world. Each cinder cone comes from a vent that opened up on the sides of the volcano.
One of the most famous cinder cone volcanoes erupted out of a Mexican corn field in 1943. The volcano erupted for 9 years, and quickly built up the cinder cone to 424 meters, and covered 25 km2 of fields in lava flows and rubble. Nearby towns were eventually buried in ash by the eruptions.