volcanoes

The explosive history of Kilauea is not well known. Today, it’s renowned for lobes of slow-moving, calm lava, which ooze out of cracks in the flanks of the volcano, pour downslope and eventually flow into the sea, where the lava cools and gradually enlarges the island. But in the past, Kilauea has erupted violently — more often and for much longer periods than was previously thought. Now, researchers have learned that over the past 2,500 years, violent eruptive periods lasting centuries have alternated with periods of quiet flows. Once an explosive period has begun, conditions on the Big Island will be very different from those on which the past hazard assessment was based.

“Volcanoes add far more carbon dioxide to the oceans and atmosphere than humans.” So says geologist Ian Plimer of the University of Adelaide in his 2009 best seller “Heaven and Earth: Global Warming — the Missing Science.” With this assertion, Plimer brings volcanic carbon dioxide degassing front and center in the climate change debate, reviving and reinforcing this wildly mistaken notion.

For a bit of money, visitors to Hawaii can indulge their touristy impulses with a single night of mai tais and luaus. But take on Hawaii’s geologic hallmarks, and you’ll embark on a low-cost safari that will last you all week.

Indonesia's Mount Merapi sent another powerful blast of searing ash and rock into the sky again on Wednesday, marking the volcano's most powerful eruptions since it began erupting again on Oct. 26.

Updated on Oct. 28, 2010:

The death toll has continued to rise from the natural disasters that struck Indonesia Monday and Tuesday. Currently, officials are reporting 343 people dead with 338 still missing from the earthquake and tsunami. Meanwhile, the eruption of Mount Merapi has killed 33 so far; after a brief lull, the eruption began again on Thursday.

Guatemala's Pacaya volcano and Ecuador’s Tungurahua vociferously erupted on Thursday, wreaking havoc on villages and cities nearby.

Earthquakes, volcanoes and blizzards, oh my. Is this year anomalous? Has Mother Nature turned on us and decided to shake up the planet? Are we headed toward an apocalypse?

You never quite know when a given volcano is going to erupt — but you can bet on it. Ireland’s biggest bookmaker, Paddy Power, jetted to fame among geologists in early January, when it announced its latest novelty bet: which of a handful of famous volcanoes around the world would be the next to powerfully erupt.

Blogging on EARTH: Iceland links and Volcanoes 301

There's a lot of great info out there about the Iceland eruption's geology, if you know where to link.

When Iceland’s Eyjafjallajokull volcano began erupting March 20, few people expected it to wind up wreaking havoc on the world’s travel. Yet that’s what it has done, as the eruption has ramped up in the last few days and is now spewing steam and ash several kilometers into the air. The winds over the North Atlantic have blown the ash cloud over Northern Europe, grounding tens of thousands of flights for myriad reasons, not the least of which is that ash can clog jet engines, causing them to fail.

For more than 9,000 years, Chaitén volcano quietly towered 1,122 meters over southern Chile. The volcano seemed almost asleep: Its wide crater, shaped by layers of ash and pumice from an ancient eruption, held two lakes and a giant dome of obsidian — the same glossy black rock that was used in prehistoric times to shape artifacts found at archaeological sites as far as 400 kilometers away. Almost at the foot of the volcano, just 10 kilometers to the southwest, a small village grew into the town of Chaitén, population 4,200.

At any given time, a massive earthquake could strike the coast of the northwestern United States and southwestern Canada, the site of the Cascadia Subduction Zone. Scientists have long known about the potential earthquake threat to major population centers like Portland, Ore., Seattle, Wash., and Vancouver, British Columbia. But scientists thought that the likely place for such a quake was off the coast.

When deep, long-period earthquakes started shaking the area around the Katla volcano on the southern tip of Iceland in 2001, officials feared it was a sign of an imminent eruption, as such quakes can be. So they were surprised when nothing happened. A new study identifies the source of the spurious signals: collapsing glaciers around the volcano, not the volcano itself. The finding may help researchers more accurately monitor other glacier-covered volcanoes.

Volcanologists have long been assessing the impacts of volcanic ash and gases on the environment and human health. This effort began in earnest when volcanologists at the U.S. Geological Survey undertook extensive studies of the environmental characteristics of ash from the 1980 Mount St. Helens eruptions. These studies included water leach tests showing that rain falling onto fresh ash can be quite acidic due to the liberation of acidic gas species that condense onto ash particles in the eruption cloud.

How geoscientists aid in the aftermath of environmental disasters

Two hundred years ago, a sea captain was sailing in the Azores, a Portuguese archipelago in the middle of the Atlantic Ocean, when he observed “an immense body of smoke rising from the sea.” As he watched, the smoke, from a volcanic vent offshore of the island of St. Michael’s, began to rotate on the water “like a horizontal wheel,” the captain wrote in his 1811 account of the event. The rotating smoke and ash grew into a dark column and ascended high into the sky, spawning waterspouts and flashes of lightning.

After a series of five explosive eruptions from Sunday night through Monday morning, Alaska's Redoubt volcano quieted for about 15 hours Monday afternoon — long enough for scientists from the U.S. Geological Survey's Alaska Volcano Observatory to travel to the volcano to make observations and repair equipment (including the Redoubt webcam). A sixth explosive eruption followed Monday night at about 7:40 p.m.