Tuesday, January 30, 2007

Volcano on the ocean floor may have caused havoc on the surface!

A wave of small earthquakes that has caused alarm in southern Chile may be related to the birth of an undersea volcano, officials said Tuesday.

More than 1,700 tremors have been recorded recently in the rugged, sparsely populated area dotted with volcanos and cut with fjords. Dozens of people slept outside or in tents on recent nights, fearing a larger quake might follow and topple their houses.

Most of the quakes have been too small to be felt, but some registered up to magnitude 4, according to the government's Emergency Bureau.

Volcano expert Juan Cayupi, part of a team that has been investigating the quakes, said scientists believe the quakes have been caused by "a magma force that is pressing up toward the surface, and is fracturing the rock" some 6 miles below the surface.

Cayupi said in a telephone interview Tuesday with The Associated Press from the area that the movement will probably result in "a small submarine volcano."

But he said "the reduced area affected" means that if a volcanic eruption occurs, it should be relatively small.

"We can safely say that there is no danger for the population" of some 35,000 people who live in Puerto Aysen and Puerto Chacabuco, the two towns closest to the Aysen Fjord.

Cayupi said the epicenter has been estimated to be 12 miles north-west of Puerto Chacabuco.
Aysen provincial Gov. Viviana Betancourt also said Tuesday that there is no danger to the population, which has remained mostly calm. She said authorities will continue to constantly monitor the situation.

Chile is an earthquake-prone nation with some 2,900 volcanoes. About 500 of them considered active though only about 60 have erupted in historic times.

Saturday, January 27, 2007

Bulusan volcano spits out ashes again!

The Philippine Institute of Volcanology and Seismology (Phivolcs) said that another ash explosion occurred yesterday morning at the summit crater of Bulusan volcano in Sorsogon province which produced ash column that rose up to One kilometer above its crater before drifting to the southwest direction.

According to its latest bulletin issued 12:00 Noon yesterday by Phivolcs Bulusan observatory said that their seismic instruments earlier recorded a total of 38 high frequency and two low frequency volcanic earthquakes during the past 24 hours before the 10::18 AM ash explosion.

The bulletin said that their seismic instrument recorded that the ash explosion lasted for about Six minutes.

Phivolcs said that prior to the explosion, seismic activity was observed to at high level and warned that yesterday’s ash explosion may signal another episode of eruptions similar to the one that took place during the period between March and October last year.

Phivolcs sais that Alert Level 1 remains in effect over the volcano, meaning people are barred from venturing within the four-kilometer permanent danger zone of the volcano.

Earlier a 10-minute ash explosion occurred at 10:06 p.m. last Wednesday although there was no visual observation due to thick clouds covering the summit area of the volcano.

Ash falls were observed at the southwest portion of the volcano at the villages of Cogon, Monbon, San Benon, Gulang-Gulang and Tinampo, including Sitio Omagom, in Irosin town.

Meanwhile, Phivolcs warned villagers living in areas beyond the four kilometer permanent danger zone to take precautions against ash falls during sudden explosions.

Phivolcs also warned residents living near river/ stream channels around the volcano should also be on alert against life-threatening volcanic flows/ lahars because ash and other loose volcanic deposits may be remobilized during bad weather conditions or when there is heavy and prolonged rainfall.

Exploration drilling may be responsible for mud volcano eruption

Gas drilling on the Indonesian island of Java has triggered a "mud volcano" that has killed 13 people and may render four square miles (ten square kilometers) of countryside uninhabitable for years.

In a report released on January 23, a team of British researchers says the deadly upwelling began when an exploratory gas well punched through a layer of rock 9,300 feet (2,800 meters) below the surface, allowing hot, high-pressure water to escape.

The water carried mud to the surface, where it has spread across a region 2.5 miles (4 kilometers) in diameter in the eight months since the eruption began.

The mud volcano is similar to a gusher or blowout, which occur in oil drilling when oil or gas squirt to the surface, the team says. This upwelling, however, spews out a volume of mud equivalent to a dozen Olympic swimming pools each day.

Although the eruption isn't as violent as a conventional volcano, more than a dozen people died when a natural gas pipeline ruptured.

The research team, who published their findings in the February issue of GSA Today, also estimate that the volcano, called Lusi, will leave more than 11,000 people permanently displaced.

Human Causes

Mud volcanoes occur when pressures deep within the Earth cause mud to squirt to the surface, said Richard Davies, lead author of the study.

"It's simply an eruption of mud and liquids," added Davies, who directs the Center for Research into Earth Energy Systems at Durham University. "There are probably a couple of thousand on planet Earth."

Typically, the eruptions are caused by tectonic forces or by the compaction of sediments at the deltas of large rivers, such as the Mississippi. "They're very common features," Davies said.

But even though an earthquake had occurred in the Java region only two days prior to the eruption, the delayed mud release almost certainly confirms a human cause, the new research points out.

If an earthquake was the cause, the eruption should have begun immediately, the scientists say.
Another unusual feature of the Indonesian eruption is that it involves a very thin, liquid mud, says Davies' colleague, Richard Swarbrick of Geopressure Technology Ltd.

That's unfortunate, because the thin mud could flow for long distances, increasing the devastation.
Also of concern is the fact that the mud is apparently being eroded out from deep underground, creating a cavern.

That means that the land around the volcano might collapse to form a crater, Swarbrick said.
The duration of the volcano's activity is also of concern.

Normally, mud volcanoes erupt quickly, then peter out to a slow ooze intermingled with the occasional major upwelling. But in Java the flow rate appears to have doubled since the eruption began, Swarbrick said.

At its center, the pancake-like deposit is already about 33 feet (10 meters) thick, Durham University's Davies added.

"It's carried on for a long time at a high rate, which suggests it's not going to stop tomorrow," he said.

Ultimately, the scientists say, they hope to learn more how to prevent such incidents from occurring in future oil and gas exploration.

Mud volcano may continue to erupt for months or even years to come!

The first scientific report into the causes and impact of Lusi, the Indonesian mud volcano, reveals that the 2006 eruption will continue to erupt and spew out between 7,000 and 150,000 cubic metres of mud a day for months, if not years to come, leaving at least 10 km2 around the volcano vent uninhabitable for years and over 11,000 people permanently displaced.

The paper by a Durham University-led team and published in the February issue of US journal, GSA Today (1), reveals that the eruption was almost certainly manmade and caused by the drilling of a nearby exploratory borehole(2) looking for gas, reinforcing the possible explanation in a UN report (3) from July last year. The mud volcano, known locally as ‘Lusi’, has been erupting for 239 (4) days and has continued to spew between 7,000 and 150,000 cubic metres of mud out every day, destroying infrastructure, razing four villages and 25 factories.

Thirteen people have also died as a result of a rupture in a natural gas pipeline that lay underneath one of the holding dams built to retain the mud. It first erupted on 29 May 2006 in the Porong subdistrict of Sidoarjo in Eastern Java, close to Indonesia’s second city of Surabaya.The team of mud volcano and pressure experts, who analysed satellite images of the area for their study, propose that a local region around the central volcano vent will collapse to form a crater.

In addition an area of at least the dimensions of the flow (10km2) will probably sag over the next few months and years.Seepage of mud and water are common on earth but usually a preventable hazard when exploring for oil and gas.Mud volcano expert, Professor Richard Davies of Durham University’s Centre for Research into Earth Energy Systems (CeREES) comments: “It is standard industry procedure that this kind of drilling requires the use of steel casing to support the borehole, to protect against the pressure of fluids such as water, oil or gas.

In the case of Lusi a pressured limestone rock containing water (a water aquifer) was drilled while the lower part of the borehole was exposed and not protected by casing. As a result rocks fractured and a mix of mud and water worked its way to the surface. Our research brings us to the conclusion that the incident was most probably the result of drilling.”“Lusi is similar to a ‘blow-out’ (eruption of water at the surface) that happened offshore of Brunei in 1979. Just as is most probably the case with Lusi, the Brunei event was caused by drilling and it took an international oil company almost 30 years and 20 relief wells and monitoring before the eruption stopped.”

Prof. Davies continued: “Up to now scientists have known relatively little about mud volcanoes and Lusi has provided the first opportunity for experts to study one from birth onwards. Our work offers a clearer understanding of how they are created and what happens when they erupt. We hope that the new insights will prove useful to the oil and gas industry, which frequently encounters pressurised fluid in rock strata that could, if not controlled, force their way to the surface during exploration drilling.

Ultimately we hope that what we learn about this incident can help insure it is less likely to happen again.”The team from Durham, Cardiff and Aberdeen Universities and GeoPressure Technology Ltd, an Ikon Science company, has essentially discounted the effect of an earthquake which occurred in the region two days prior to the mud volcano as the cause of the eruption.

This is based on the time-lapse between the earthquake and the eruption, the fact that there were no other mud volcanoes in the region following the earthquake and through comparison with other geological examples.

(1) Published by the Geological Society of America

(2) The borehole is owned by Indonesian gas company Lapindo Brantas

(3) As reported in Environmental Assessment: Hot Mud Flow East Java, Indonesia.

Final Technical Report: United Nations Disaster Assistance and Coordination mission in June and July 2006 and Follow up mission in July 2006. 2006, published by Joint UNEP/OCHA Environment Unit.

Auckland volcanoes could erupt together

Five of Auckland's volcanoes could be in danger of erupting at the same time. That is according to a study released today. The Auckland University study shows Puketutu, Crater Hill, Wiri, Mt Richmond and Taylor Hill erupted within years of each other.

Dr John Cassidy's research also suggests Auckland could be at risk of future simultaneous multiple eruptions. He says the research was done by studying volcanic rocks which have recorded unusual disturbances in the Earth's magnetic field.

Saturday, January 20, 2007

Lassen Peak is not extinct and could be active sooner than later

The landscape here speaks clearly, in a rumbling voice, saying it was forged over millions of years by the irresistible powers of fiery volcanoes and glaciers of ice, when chaos and upheaval ruled.
Now Lassen Volcanic National Park is mostly cooled off, calmed down and resurrected. Nature found a way to populate the hundreds of volcanoes and their remnants with 700 species of flora and nearly 300 kinds of animals. Flower-covered meadows, rushing streams and 200 lakes are spread throughout the park, all accessible via 150 miles of hiking paths.

Pioneers came this way in the 1850s on the Nobles Immigrant Trail, parts of which are plainly visible. The descendants of the Mountain Maidu Indians, who once thrived here, hold the area sacred and attend it on their spiritual quests.

Looming over the park like a great stone god in the sky is snow-topped Lassen Peak, an 11,000-year-old "plug dome" volcano rearing up to 10,457 feet. The lowest elevation in the park is 5,650 feet.

We were discussing all this while touring the Sulphur Works, near the park's southwest entrance. It's a geothermal area where steam vents and boiling mud pots fill the air with heat and stinky smells.

It is believed that the Sulphur Works once was near the heart of Mount Tehama – aka Brokeoff Volcano – an "andesitic stratovolcano" formed 600,000 years ago. It spewed magma for centuries, building itself up to a height of about 11,000 feet, experts say, with a base of 11 miles. Eventually, it eroded under glaciers and collapsed.

The now-dominant Lassen Peak is part of the "Ring of Fire," a chain of volcanoes that traverses the west and east sides of the Pacific Ocean and extends to Indonesia.

"The park is all about geological wonders," said National Park Service ranger Karen Haner, who was guiding us around. "It's pristine, and you can get on a trail and very quickly be all alone."
Haner is the park's chief of interpretation and cultural resources, and has been stationed here for eight years. She and her fellow rangers are charged with preserving the park in its natural state, and they take that duty very seriously.

For recreationists, Lassen is an obvious choice as an alternative to the larger and much more crowded Yosemite National Park, which receives 4 million visitors a year, compared with Lassen's 375,000 or so. Both parks are open year-round.

Lassen offers camping, hiking, fishing and incredible vistas – though on a smaller scale than Yosemite – and is surrounded by the million-acre Lassen National Forest.

One thing the park is lacking, though, is lodging.

"There is a segment of our visitors who are not interested in camping out," Haner said. "They want some accommodations, but we don't have any to speak of."

The only lodging in the park is the small Drakesbad Guest Ranch, a remote outpost that's often booked a year in advance.

Also, while Yosemite's valley floor is accessible in the winter, Lassen must contend with a snow factor that shrinks its season.

On average, 35 feet of snow falls here, making it impenetrable for months to all but dedicated cross-country skiers and snowshoers.

During our visit last July, 25 percent of the park – mostly backcountry trails and lakes – was still snowbound, including its premier geothermal viewing area, Bumpass Hell. The 30-mile-long Main Park Road (Highway 89, aka federal highway NPS-1),had opened earlier in the month.

The narrow, 30-mile road winds its way mostly along the west side of the 106,000-acre park, passing near numerous points of interest.

Driving on the road and making frequent stops "is how half of our visitors experience the park," Haner said. "The road is on the National Register of Historical Places as a cultural landscape."
We climbed into the SUV and motored on from the Sulphur Works, passed by the Brokeoff Mountain trailhead (a four-hour round-trip hike to 9,235 feet) and stopped at Peak Necessities, an interim concession that sells everything from hiking sticks to plush toys.

"This will be the site of the Kohm Yah-mah-nee Visitor Center," Haner said. "Kohm Yah-mah-nee" is Maidu for "snowy mountain."

The year-round staffed center – a first for the park – will showcase interpretive exhibits and movies, host special events, and sell food and souvenirs. The projected opening is in fall 2008.
We continued our ascent toward Lassen Peak, passing Emerald Lake and Lake Helen, both mostly frozen over, but both revealing patches of neon-blue and green water. Snow berms 15 feet high shouldered both sides of the road.

Soon, we pulled in to the Bumpass Hell parking lot, where we encountered Rachel Steele and her daughter, Talulla, 7, before they returned to Los Angeles.

"We wanted to get out of the city and be in the frontier, so we've been visiting Mount Shasta," said Rachel Steele. "We came here because the budding vulcanologist in the family (nodding toward her daughter) was interested in checking out some geothermal action on the edge of the Ring of Fire.

"(The park) is absolutely gorgeous. It smells so piney up here."

At the edge of a nearby cliff was a 13-foot-high boulder, carried by glacier and deposited there millenniums ago. It seemed impossible, but foreshadowed even more bizarre sights to come.
We drove on to a roadside pull-off to check out Hat Lake, which flows into Hat Creek and faces the north slope of Lassen Peak.

"Hat Creek was a fishing ground for the Atsugewi Indians," Haner pointed out as we walked along the stream, then crossed the road for a look at shallow Hat Lake. Beavers had built a dam there, and their lodge could be seen at the lake's far end.

Farther along, we pulled off to examine the five kinds of volcanic rocks that erupted from Lassen Peak early in the last century. Thousands of pieces litter the ground.

Also here are gigantic boulders that were swept down the mountain. The boulders were called "hot rocks" because they were sizzling when they came to a halt and took days to cool off. As they cooled, some of them shattered into pieces that, theoretically, could be pieced back together like gigantic jigsaw puzzles. Nearby is the imposing 20-ton Loomis Hot Rock, carried miles from Lassen Peak during an eruption.

In 1914, Lassen Peak began a series of eruptions that continued until 1921. The biggest explosion came on May 19, 1915. A gush of molten lava and rocks shot out onto the snow, vaporizing it and creating a 20-foot-tall flow of mud, boulders and trees that rushed down the slope and extended for miles. It wiped out everything in its path and created what's known as the Devastated Area. Since then, a pine forest has partially covered the damage. Local resident Benjamin Franklin Loomis' primitive photographs of the event as it occurred are still used as data by scientists.

Next we came to Chaos Crags, a group of dome volcanoes that surrendered to erosion and gravity about 300 years ago. Millions of tons of dacite rock crashed down the slope at 100 mph, took out the forest and dammed a creek, creating nearby Manzanita Lake. The area is called Chaos Jumble. If you were to grow a crop of big rocks in a huge field, this is what it would look like at harvest time.

At the Lassen Volcanic Discovery Center, interpretive panels, dioramas and a topographical map help explain the history of the park. Included in displays are Loomis' original camera equipment used to photograph the Lassen eruption, along with blowups of his photos.

"If Loomis hadn't run out of film and left, he would have been killed," Haner said.

Soon we were at peaceful Manzanita Lake, looking up at a nearly full moon as it rose over Lassen Peak.

We saw some trout activity during our stroll around the lake, but anglers should note that hooks must be barbless and that fishing is catch-and-release.

The next day we drove to the 110-year-old Drakesbad Guest Ranch in the remote Warner Valley.
The compound of wood buildings includes a rustic lodge, dining hall, guest rooms and horse stable. Down a path is a swimming pool fed by a hot spring. A deer wandered into camp and watched the guests watch her.

We ran into ranger Chris Cruz, a 25-year National Park Service veteran who has worked in 10 parks.

"Lassen is as good as any of them," he said. "This park is off the beaten path, so you have to make a conscious effort to get here. (Consequently) the thing that's really nice about it is we don't get the visitation like they do in, say, Yosemite, the Grand Canyon, Sequoia and Kings Canyon."
A few minutes later, three hikers returned from a nearby trail and reported spotting Buttermilk and her two cubs ambling in the woods, so we took off to find the black bears and visit the Devil's Kitchen, two miles distant.

The trail took us through a green fen – a lush meadow kept wet from groundwater – and then took off uphill into a forest of old-growth incense cedar and ponderosa pine, the original big guys that avoided the woodcutters' saws of the 19th century. Mosquitoes rule the woods, so bring repellant.
No sign of the bears except for a pile of scat.

Our last hike took in three of the park's most startling sights, the Cinder Cone volcano, the Fantastic Lava Beds and the Painted Dunes.

We pulled into the Butte Lake parking lot and looked across the water at a startling sight – a 50-foot-high wall of sharp-edged volcanic rock that parallels the four-mile uphill trail to Cinder Cone (a national monument), and also marks the western edge of the sprawling Fantastic Lava Beds.
Essentially, Cinder Cone is a 700-foot-high pile of volcanic cinders – think of black sand – that formed around a volcanic vent during two eruptions in the 1650s. A steep trail leads to the top.
One obvious concern for park visitors is the possibility of another volcanic eruption.
What's the status?

"Lassen Peak is categorized as a dormant volcano, but it is not a dead volcano by any means," said Patrick Muffler. He is the geologist emeritus with the U.S. Geological Survey and has devoted 30 years off and on to studying the geothermal aspects of the park.

"It could be thousands of years before it erupts again, or sooner," he said. "This is not an exact science."

Mount Karthala's activity puts the Comoros Islands on alert!

Earth tremors from Comoros' volcano Mount Karthala grew stronger and more frequent, residents said on Sunday, forcing thousands of nervous families to sleep outside overnight for fear their homes might collapse.

The Indian Ocean archipelago's largest island, Grand Comore, was put on red alert after Mount Karthala -- one of the world's largest active volcanos -- began to glow red and emit suffocating fumes late on Friday.

The 2,361-metre (7,746-foot) Mount Karthala dominates Grand Comore, but its eruptions, which happen on average every 11 years, have rarely caused a major disaster.

But while lava levels inside the crater have subsided, earth tremors have become more frequent.
Hamidou Soule, a geologist who leads the Karthala surveillance centre, said tremors were lasting up to five seconds and had reached five on the Richter scale.

"The lava and the gases remain trapped and are looking to crack through the mountain. It seems the main chimney is blocked," he said. "The frequency of the tremors shows that a (lava) flow could happen in any part of the island."

Residents said people were prepared to evacuate.

"The tremors get stronger and stronger every 15 minutes," said Ibrahim Youssouf, a photographer from Mitsoudje village on the volcano's southwestern slope. "A good number of people have packed their bags, ready to flee in case of eruption."

Another resident from a village on the volcano's western slope said high temperatures had made the air dry.

"It feels like everything will explode," he said.

In the capital Moroni, thousands slept outside overnight and national radio broadcast appeals for calm and readings from the Koran across the mainly Muslim island.

"When I felt the tremor, I woke my wife and we stayed in the garden," said resident Abderemane Koudre. "We thought the house was going to collapse. It was frightening."

In 1903, 17 died from noxious fumes that seeped from cracks, and the last big eruption was in April 2005 when thousands fled in fear of poisonous gas and lava.

Sunday, January 14, 2007

Comoros' volcano displays signs of activity

Comoros' Mount Karthala begun emitting fumes and producing a red glow over the top of its volcano, residents said on Saturday as the Indian Ocean archipelago's main island was put on alert.

The 2,361-metre (7,746-foot) Mount Karthala, one of the world's largest active volcanoes, dominates the island of Grand Comore but its past periodic eruptions have rarely caused a major disaster.

"Since yesterday evening, the volcano has become eruptive," Hamidou Soule, a geologist who heads the Karthala volcano surveillance centre, told Reuters.

He said the lava level had risen in the volcano's crater. Mount Karthala has erupted every 11 years on average for the last two centuries.

Residents of Mvouni, a town at 1,000 metres altitude on the volcano's west slope, were woken up by strong fumes.

"My neighbour woke me at two o'clock in the morning and we saw the red glimmer in the sky," said resident Halima Ahamada.

"A strong smell of burning earth took us by the throats."

Colonel Ismael Daho, head of the emergency management team for the archipelago, said Grande Comore had been put on red alert.

In May, the volcano frightened thousands of residents when it bubbled lava and lit up the night sky, but later stabilised.

The last big eruption, in April 2005, sent thousands fleeing in fear of poisonous gas and lava.
The worst disaster on record came in 1903, when 17 died from noxious fumes that seeped from cracks.

Auckland volcanoes pose an important threat!

"That amount of ash would cause chaos in Auckland," said GNS Science volcanologist Graham Leonard. "From a hazard point of view, that is pretty significant".

The research – which casts new light on volcanic threats to New Zealand's biggest city and a third of the nation's population – springs from the Auckland Maar Volcano Drilling Programme.

A partnership between Auckland University and GNS Science it was started to collect drill cores providing a record of longterm climatic changes, but the drill cores have also thrown new light on past eruptions.

The barge-mounted drill rig anchored in about 2 metres of water is expected to finish its work today.

Some of the cores in the Orakei Basin have shown the Orakei volcano is probably three times as old as previously thought, and by drilling 81m into the sediment beneath the basin the scientists have identified ash layers from 90 eruptions in about the past 90,000 years.

Until now, scientists believed the Orakei volcano was about 20,000 years old.

One ash layer more than 10cm thick was from the Lake Rotoiti area in the Bay of Plenty, and thinner layers came from eruptions at Mayor Island, Taupo, Mt Tongariro, and Mt Taranaki.

The scientists have identified at least 50 different ash layers from Auckland volcanoes such as Little Rangitoto, Mt Hobson, The Domain, Mt St John, and One Tree Hill.

Each of the 50 volcanic cones scattered around Auckland has been fed by a plume of molten basalt which can force its way to the surface quite quickly, at speeds of about 5kph, according to Auckland University research published on the GNS website.

There appears to be a trend towards an increase in the average size of eruptions, which have been of two main types.

Phreatomagmatic eruptions – violent explosions of steam, gas, lava and rock triggered when water and magma mix. These typically create a maar (CRRCT) volcano with a crater up to 1km, such as the Orakei Basin, and make up 72 per cent of the Auckland volcanoes. The other main type of volcano is the scoria cones such as One Tree Hill.

Experts have predicted that in future explosive eruptions in Auckland volcanic ash falling from the air may slash visibility or even cause complete darkness, damage electrical equipment, immobilise motor vehicles, and short-circuit communication systems and electricity supplies.
Even small amounts can damage vegetation and affect the breathing of people and animals, while attempts to wash it away will clog drainage systems.

Over 70 per cent of the Auckland volcanoes have also had fire-fountains of incandescent magma, and 30 of the volcanoes have had lava flows.

Auckland has a big volcanic eruption every 5000 years on average and the last one was Rangitoto, about 600 years ago.

According to the university's head of geology Ian Smith, monitoring will give a warning of "days to weeks" before the next eruption.

The 360sqkm covered by the Auckland volcanic field stretches from Rangitoto Island in the north to Manurewa in the south.

The Soufriere spits up ashes too!

The Soufriere Hills volcano sent a plum of ash five miles high Jan. 8 after authorities warned Jan. 4 that the volcano’s dome had topped the crater rim.

Areas around the volcano are at risk and the government has ordered evacuations, but since the capital city of Plymouth was inundated by a massive eruption in 1997, a new capital has been planned and construction is underway on the northern side of the island away from the volcano’s wrath.

Volcano Telica spits up ashes!

Volcano Telica discharged enormous quantities of gas and ash on Tuesday after a strong eruption, but caused no damage, according to the Nicaraguan Territorial Studies Institute.

Strong eruptions persisted for several hours, but no people were in danger, according to eyewitnesses. The last major eruption of the 1060-metre volcano, 120 kilometres north-east of Managua, was in 1948.

The eruption was low intensity, but stronger than the volcano[0x2019]s normal activity, according to seismologist Alejandro Morales from the Nicaraguan Territorial Studies Institute.

Wednesday, January 03, 2007

Can new research change our knowledge about volcanoes?

Ordinary volcanoes spew lava, erupting magma, from cones or vents. But in the case of a supervolcano, the underground magma chamber bursts out in a titanic explosion with a force thousands of times that of a normal eruption and huge amounts of ash, dust, and poisonous sulphur dioxide are thrown into the atmosphere, leaving a giant crater or caldera.

Such large eruptions of greater than 100 cubic kilometres of magma are generally rare and random events worldwide.

But geologist Darren Gravley of Auckland University and his colleagues have shown that one of the largest supervolcano eruptions on record, at Taupo 250,000 years ago, was twice as big as previously thought.

They have published in the Bulletin of the Geological Society of America evidence that the eruption in the Taupo Volcanic Zone was actually two supervolcanoes 30km apart which erupted within days or weeks of each other.

It is the first time such a close pairing of supervolcano eruptions has been documented and provides scientists with a new understanding of the potential linkage between geographically separate caldera volcanoes. Each eruption belched out more than 100cu km rock and volcanic ash, creating what are now known as the Mamaku and Ohakuri volcanic deposits.

"It's possible one of these triggered the other," said Gravley. But exactly how the triggering might have worked is uncertain.

What is clear from the university's explorations is that they were created very close in time – a surprising discovery because most caldera or "supervolcano" eruptions in any one region tend to be tens of thousands of years apart, according to accepted theories.

Among signs the rocks from the two eruptions were piled on one another is the lack of erosion on the first volcanic deposits – which is striking, considering the eruptions would have been followed by heavy rains.

Previous studies that looked only at the radioisotope dates of the volcanic rocks from the eruptions missed the timing details, Gravley said, as they had a margin of error of 10,000 years.

"You've got to look at the physical evidence," said Gravley. "It's really getting into the nitty-gritty. From the stratigraphy (rock layers) it's clear two were erupting at the same time. That just blows away any (regional frequency) studies out of the water."

The bad news is that double eruption represents a whole new way that supervolcanoes can threaten humanity.

Caldera researcher Gerardo Aguirre, of Mexico's National University in Juriquilla, said caldera eruptions were far less frequent than other volcanoes.

But when they did erupt, "the consequences for the surroundings and in general for the world would be enormous, because these explosive eruptions are many orders of magnitude bigger than a more common eruption from a volcano, such as Mount St Helens or Vesuvius."

Last year, other research at Taupo – on the more recent Taupo supervolcano of only 26,500 years ago – changed accepted theories that it takes hundreds of thousands of years for the reservoir of molten rock, or magma, beneath a supervolcano to build up to an eruption. They showed the period between super-eruptions can be much shorter, perhaps a few tens of thousands of years.
Dr Bruce Charlier, from Britain's Open University, showed the build-up at Taupo was no more than 40,000 years – a relatively short time period in geological terms.

"Our findings mean that we have to reassess our understanding of the speed at which the volcano can reactivate, and this has important implications for volcanic monitoring and hazard mitigation at Taupo and similar volcanoes worldwide."

Monday, January 01, 2007

Is Aconcagua really the highest volcano in the world?

Here’s a spoof for Seven Summit summiteers- which is really the highest mountain in the Andes: long time accepted Aconcagua or its northern sister, the dormant volcano Ojos del Salado?

A similar scenario raised its head in the mid 80’s around Everest and K2. Just as it was getting really popular to climb Everest, someone through a spanner in the works and questioned whether it was indeed the highest mountain in the world, or if the more dangerous and more difficult K2 in the Karakorum was not higher.

The media caught on and hyped it up, and a whole bunch of Italians got excited (the Italians made the first ascent of the climb in 1954). Ardito Desio, the aging leader of the expedition and a famous Italian geographer returned to the mountain to measure it again, confirming it was no doubt 8611 metres high, more than 200 metres lower than Everest.

Now at the end of 2006 Aconcagua, South America’s highest mountain has been questioned. According to some Chileans, Ojos del Salado, a massive volcano in the northern desert region may not only be taller, but may exceed 7000 metres in height.

It may be amusing to note that while Aconcagua sits within Argentinean borders, Ojos del Salado marks the border between the two countries and the most frequented approach to climbing it starts from the Chilean side. One can only imagine the revenue for the country if every Seven Summits Summiteer and Seven Summit hopeful would have to now climb a new peak in South America.

While this first issue may be something of a national feud, the second claim, that it may exceed 7000 metres represents more of a continental, if not global hope. In the world as we know it, no mountain outside of the Himalayas exceeds 7000 metres. Aconcagua sits on the official’s books at 6971 metres. Having climbed in the Andes, I can testify that this is a difficult statistic for South American mountaineers and South Americans in general.

If prompted locals will often say that South American cartographers measure the mountain at 7004 metres, while the Europeans claim it to be 6971. If indeed Ojos del Salado is 7000 metres plus, it opens the mountain (and Chilean tourism) up to a whole new bunch of peak baggers, those of the ‘only mountain outside of the Himalayas exceeding 7000 metres’.

According to MountEverest.net, a local Chilean publication "Andes magazine" published testimonies from climbing pioneers stating these claims. During the first summit of the peak made by Chile in 1956, the climbers led by Colonel René Gajardo, measured the peak at 7084 metres high.

In the same year, a US team led by Adams Carter and sponsored by the American Alpine Club also measured Ojos del Salado, stating it was 6885 metres high. The prestigious AAC's claims were generally accepted, despite Carter's team never reaching the summit.

This year the Andes Magazine contacted the now 84-year-old Gajardo, who claims there is a reasonable doubt on the subject. With regard to Carter measurements, Gajardo also believes the North Americans mistook the main summit of Ojos del Salado, and measured another peak instead.

In addition, French climber Philippe Reuter made US Air force aeronautical charts note the peak as 7083 metres high.

Andes Magazine (and Chileans) have called for a re measuring of both peaks. The most recent official measuring of both mountains was in 1989, when a team from the University of Padua in Italy, aided by Argentinean climbers and geologists, surveyed both Aconcagua and Ojos del Salado, using GPS technology.

Ojos del Salado came out at 6 900 metres while Aconcagua seemed higher at 6 962 metres, with a possible error of plus/minus five metres. None of the measurements were high precision however, so the debate continues. Response to the article has been varied, with more than a number of people, including South Americans calling the claims as nothing less than ridiculous.
Ojos del Salado is the highest volcano in the world. It is a massive volcanic complex with numerous craters, cones, and lava domes. No historical eruptions have been recorded, but fumarol activity is present.

The mountain is located in the extremely dry and harsh Atacama Desert, with snow only remaining on the peak during winter. The first ascent was made in 1937 by Polish Jan Alfred Szczepañski and Justyn Wojsznis.

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