Saturday, February 23, 2008

Discovery of buried volcano

Geologists have discovered a buried volcano inside Auckland's Panmure Basin while drilling to find out more about the volcanic history of the area.

The GNS Science team were drilling from a barge at the basin, itself the mouth of a volcano that erupted about 28,000 years ago.

The new volcano is believed to date back to a similar point, and experts are already hailing it as an exciting find that gives a greater understanding to the clustering of volcanic eruptions in the Auckland region.

Auckland sits on 49 volcanoes, so dragging up a fiftieth from the murky waters of the Panmure Basin is exciting, but perhaps not suprising. However, GNS scientists say it is extremely rare for two eruptions to have occurred at the same site in the Auckland volcanic field.

Dr Graham Leonard of GNS Science says the discovery means that "there are two different types of eruptions going on here - the very explosive one, for the basin, and the fire fountaining to produce the cone in the middle of the lake."

New Zealand geologists hold particular interest in sites like Orakei, Lake Pupuke, and the Panmure Basin. In most cases, these soft spots in the earth can hold the answer not only to the past, but the future.

Leonard believes that the new site is "a nice record" that will help researchers understand what happened at Mt Wellington.

This would be no small feat, considering that Mt Wellington is several milennia younger than the basin cones. It only blew its top around nine thousand years ago.

While it is unusual for eruptions to happen twice in the same place, Leonard's team have based on the large flow of magma 80 kilometres below the area's surface.

"You can imagine something coming to the surface from 80 kilometres' depth would find several pathways to that surface."

In fact, it would not even be a first for Auckland. A repeat eruption happened on Rangitoto only 650 years ago.

The drilling was part of a three-year project intended to gain insight into Auckland's volcanic history, and perhaps prepare the city for another big bang. Core samples will be analysed at Auckland University to try to work out the exact dates of each eruption.

Volcanoes are linked to historic legends

STANDING at almost 11,000 feet, Mount Etna dominates the Sicilian skyline.
It is the most active volcano in Europe.

The Romans believed it to be the home of Vulcan, the god of fire.

And to them, Mount Etna erupting merely meant Vulcan was forging weapons for Mars, the god of war.

Since 1500BC the volcano has erupted around 200 times, with lava flows halting just miles short of the nearby town of Nicolosi.

But regardless of the history of Mount Etna, the people who live within the volcano’s destructive reach seem completely unfazed.

Near the foot of the volcano, there are a multitude of vineyards and olive groves.

As you climb higher, the lowlands evolve into dense woods sheltering a surprisingly large number of animal species that call the mountainside home.

Dotted with snow most of the year, some of the lava is 300,000 years old.

In the past, scientists have used this area to test robots before they send them to Mars because the atmospheric and geological conditions are so similar.

The most violent eruption in the history of Mount Etna occurred in March, 1669.

On the first day, lava flows cut a smouldering gash out of two mountain villages and continued to spew molten rock for days.

Saturday, February 16, 2008

Ashes from Ecuadorian volcano destroys crops

Ash from Ecuador's erupting Tungurahua volcano caused major crop damage and has covered the nearby city of Riobamba.

The country's geophysical institute said some 135,000 residents were affected especially in the districts of Guano, Colta, and Penipe.

The 16,477-foot Tungurahua is spewing a permanent column of ash to the northwest up to four kilometer high.

In February 6, Tungurahua had a medium sized eruption, releasing lava, rocks and gases along with ash, forcing the evacuation of several villages. The eruption has been smaller compared to blasts in July and August of 2006.

The blast on August 2006, killed five people and inundated three villages. After an 80 sleep, the volcano became active in 1999.

The volcano is located in the tourist hub of Banos in central Andes, 150 kilometers km southeast of the capital Quito.

Ecuador could face more volcanic eruptions

Ecuador’s 16,575-foot Tungurahua volcano spewed ash and incandescent rocks yesterday as experts warned that a more violent eruption is likely.

Tungurahua shot a three-mile column of ash into the sky, and fiery rocks rolled down its flanks. On Wednesday, it blasted ash 6 miles into the air.

“The volcano continues to be very unstable,” Hugo Yepes, the director of Ecuador’s Geophysics Institute said, adding that there are “strong possibilities” that a stronger eruption will occur. Civil Defense officials said they have evacuated 1,500 villagers living near Tungurahua’s flanks.

Saturday, February 09, 2008

Fatal eruption in Ecuador

At least five people died when the Tungurahua volcano erupted in Ecuador, according to local media reports.

The 5,023-metre colossus, 130 km southeast of the capital, threw lava, boulders and clouds of ash into the air the whole of Wednesday.

Five nearby villages were heavily damaged and 1,450 people were evacuated, the El Universo newspaper reported Wednesday evening.

President Rafael Correa declared a state of emergency in the region, and the clouds of ash had damaged 20,000 hectares of farmland.

Hugo Yepez, director of the Geophysics Institute of Ecuador, warned of a major eruption of the volcano, which has been actively spewing ash, rock and lava since early January. After lying dormant for years, Tungurahua has been active since 1999.

Antartica sits on active volcano

In February's edition of Nature Geoscience there is an interesting article about a volcano. While volcanoes are interesting in their own right, this one stood out because it is an active volcano that is erupting under Antarctica. The volcano, situated on the West Antarctic Ice Sheet, first erupted in 207 BC—about 2,000 years ago—and remains active to this day.

This volcano is not directly observable—its existence was discovered due to a layer of ash covering an elliptical area nearly 23,000 km2 that resulted from a past eruption. The data was gathered by the British Antarctic Survey, which puts the volcano's location in the Hudson Mountains at 74.6oS 97oW. Lead author of the study Hugh Corr of the BAS says that "[they] believe this was the biggest eruption in Antarctica during the last 10,000 years." The authors state that the substantial blast blew a hole in the ice sheet and shot a plume of ash and smoke over 12 km in the air.

As Antarctic glaciers are disappearing, this find offers up a new clue to the puzzle. The Pine Island glacier on the West Antarctic sheet has been accelerating its flow towards the coast, and its proximity to this newly found volcano could help explain the speed up, as residual heat from past eruptions could produce a source of water to lubricate the glacier's flow. However, the authors point out that the larger problem of glacial thinning in the West Antarctic sheet cannot be explained in full by this event, and they theorize that warming ocean waters play a large role.

Chilean volcano erupts!

Southern Chilean volcano Llaima began erupting again early Sunday, triggering around 10 earth tremors, but so far there are no reports of deaths or serious injuries.

A 2km river of lava melted glaciers as it flowed down the side of the mountain. Emergency authorities said avalanches were the largest risk posed by the erupting volcano.

Residents of Melipeuco, the village closest to the 3,125-meter-high mountain, were worried about the eruptions intensifying and becoming more dangerous. However, specialists from the Southern Andes volcano observatory, who flew over the volcano in a helicopter, said the lava was flowing toward Cherquenco, away from Melipeuco.

Llaima previously erupted on Jan. 2. With at least 60 substantial eruptions since records began, Llaima is one of South America's most active volcanoes. It is located in the Conguillio National Park, some 650 kilometers south of Chile's capital Santiago.

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