[Vulkanen] The ring of fire #6: Waar diverse vulkanen puffen

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Op zondag 5 januari 2014 08:32 schreef Perrin het volgende:

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Ash explosions at Mt. Marapi on Sumatra

Bukittinggi, West Sumatra (ANTARA News) - Mount Marapi in West Sumatra expelled thin grey smoke up to 200 meters from the crater into the sky, on Wednesday morning, stated spokesman of the Bukittinggi Volcanology and Geological Disaster Mitigation Agency (PVBMG) Warseno.

"The volcano spewed smoke after it showed signs of increased activity at 7.28 a.m. local time on Wednesday. Local residents should therefore, continue to stay alert," he warned.

The volcano, located in the Tanahdatar and Agam districts, West Sumatra, remains on the second highest alert level.

People living within 3-km radius of the crater are banned from climbing the volcano.

Mt Marapi is one of the active volcanoes in West Sumatra. It had sent out sulfuric volcanic ash, one thousand meters into the sky, on August 3, 2011. The ash had fallen over several areas, such as Agam, Tanahdatar, Padangpariaman and Padangpanjang.

The volcano is also considered a conservation area as well as a tourist destination in West Sumatra.

When inactive, the mountains adjacent to Mount Singgalang and Mount Tandikek have always been a destination for climbers from within and outside West Sumatra. During every New Year, it is gets crowded with trekkers.

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North Sumatra’s Mount Toba may erupt again, at any time

Geologists and geophysicists say that Mount Toba, which erupted thousands of years ago, turning into Lake Toba, still contains a dangerous magma chamber and its activity needs further study.

Indonesia Geological Experts Association president Rovicky Dwi Putrohari said the magma chamber could be observed in a study conducted by researchers recently. Rovicky added that researchers used the tomography method to detect the magma chamber.

Researchers said the Mount Toba magma chamber was located at a depth of between 20 kilometers and 100 kilometers.

“The method was used in the early stage of the study. Our researchers were able to find the location and dimensions of the magma chamber of Mount Toba. Later research will find out the potential volume of magma in the volcano for triggering an eruption,” Rovicky told The Jakarta Post on the sidelines of a joint conference between the Indonesian Geological Experts Association and Indonesian Geophysics Experts Association in Medan, North Sumatra, recently.

Around 800 geologists and geophysicists took part in the conference, including scientists from Australia, France, Malaysia, Singapore and the United States.

Rovicky said that during the three-day conference several studies related to the Mount Toba eruption were presented by experts, including Craig A. Chesner, from the Eastern Illinois University in the US.

Rovicky explained that based on Chesner’s study in 2011, it was concluded that the current Lake Toba was the result of four previous eruptions.

The first eruption took place around 1.2 million years ago at the northwest end of Lake Toba, the second was around 840,000 years ago south of Lake Toba, encompassing Parapat and Porsea, the third eruption occurred around 500,000 years ago at the northern end of the lake between Silalahi and Haranggaol, and the fourth eruption occurred some 74,000 years ago which resulted in the present state of Lake Toba, with Samosir Island in the middle. Its depth is estimated at 500 meters.

Rovicky said Mount Toba was regarded as a super volcano as it had a huge magma chamber, which, if it erupted, would leave a massive caldera, like Lake Toba today.

Rovicky added that the magma chamber inside the volcano could erupt any time if the Sumatra fault line reactivated.

The Sumatra fault line bisects Sumatra Island from the northwest in Aceh to the south in Lampung. The fault line runs through Mount Toba.

“A quake could reactivate the magma chamber which is so far dormant. That’s why we believe Mount Toba could erupt again at any time. When it will be, we don’t know. Thorough and continuous research is needed to find that out,” said Rovicky.

Andi M. Adiwinata, from the Indonesian Geophysics Experts Association, said the scientist who detected the presence of the magma chamber in Mount Toba was Sri Widyantoro, from the Bandung Institute of Technology. Andi added that the detection was carried out using the tomographic technique.

Andi said Mount Toba had currently attracted the attention of local as well as foreign researchers thanks to its massive and devastating eruptions in history. He said a joint team of Indonesian scientists had been formed from relevant institutions, including the Indonesian Institute of Sciences (LIPI) and the Meteorology, Geophysical and Climatology Agency (BMKG), to conduct mitigation studies regarding the latest condition of Mount Toba.

“The researchers are currently working to find out how big the potential threat from Mount Toba is. Despite being categorized as inactive, its development needs further monitoring,” said Andi, adding that besides Mount Toba, 129 active volcanoes in Indonesia were also being monitored.

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Shishaldin Volcano's Alert Status Upgraded After Unusual Activity

The Alaska Volcano Observatory upgraded the alert level at Shishaldin Volcano in the Aleutian Islands Thursday after seeing some unrest at the summit.

AVO scientist Kristi Wallace says the unusual activity at Shishaldin began Wednesday.

"Little bit ago, AVO changed the color code at Shishaldin from green to yellow based on increased temperatures at the summit crater of Shishaldin Volcano as well as increased steaming yesterday," she says. "Both of those observations were observed via satellite imagery.

Wallace says the observations don’t mean Shishaldin is in imminent danger of eruption. The yellow status just indicates behavior that isn’t normal.

Shishaldin is the highest peak in the Aleutians, rising about 9,400 feet above sea level. It’s located on Unimak Island about 100 miles northeast of Unalaska.

Shishaldin was last elevated to yellow in 2009, when the same kind of activity occurred. Wallace says that anomaly didn’t result in anything more serious.

Historically, though, Shishaldin has been very active:

"It’s erupted approximately 28 times since 1775, so in historic times it’s erupted quite frequently, although the eruptions are typically low-level plumes and ash and steam plumes," Wallace says. "So [it's] not a particularly dangerous volcano, although the eruption that occurred in 1999 did send ash plumes as high as 45,000 feet above sea level."

Wallace says the AVO is going to keep monitoring Shishaldin for signs of explosions. But the seismic stations closest to the summit aren’t working right now. That means using more distant monitoring points as their main sources of data.

"There’s a whole network of stations, so we’re just relying on other stations that are not quite as close to the summit area where we’re seeing the activity," Wallace says. "Hopefully those will be enough for us to pick up a seismic signal, although this volcano’s not just monitored with a seismic network. We’re still using satellite imagery, and then the infrasound stations which are good at detecting explosion signals."

There are two other volcanoes in the Aleutians currently on a yellow alert. Those are Cleveland, 175 miles southwest of Unalaska, and Veniaminof, northeast of King Cove.

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Op donderdag 13 februari 2014 19:55 schreef stan12 het volgende:

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Remote Alaska volcano might erupt soon, experts say

Alaska's Cleveland Volcano could soon be leaking from its flanks if the lava inside continues to build up, officials at the Alaska Volcano Observatory reported.

The observatory reported that the volcano's lava dome was 262 feet in diameter on August 30 and has now expanded to 394 feet.

"The presence of the lava dome increases the possibility of an explosive eruption, but does not necessarily indicate that one will occur," the observatory said. "Short-lived explosions could produce an ash cloud that exceeds 20,000 ft above sea level."

The observatory said it did not expect air travel problems if the volcano erupted.

Because "the small lava dome in the summit crater has resumed growth and now fills the floor of the crater," the observatory is raising its alert level.

The remote volcano is in the Aleutian Islands, about 940 miles southwest of Anchorage.

Because the volcano is in such a remote area, the observatory webcam feed has experienced technical difficulties.

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Magma rising in Washington state's Mount St. Helens volcano

(Reuters) - Magma levels are slowly rebuilding inside Mount St. Helens, a volcano in Washington state that erupted in 1980 and killed 57 people, although there was no sign of an impending eruption, U.S. scientists said.

The roughly 8,300-foot volcano erupted in an explosion of hot ash and gas on May 18, 1980, spewing debris over some 230 square miles and causing more than a billion dollars in property damage. Entire forests were crushed and river systems altered in the blast, which began with a 5.2 magnitude earthquake.

"The magma reservoir beneath Mount St. Helens has been slowly re-pressurizing since 2008," the U.S. Geological Survey said in a statement on Wednesday. "It is likely that re-pressurization is caused by (the) arrival of a small amount of additional magma 4 to 8 km (2.5 to 5 miles) beneath the surface."

The USGS said this is to be expected with an active volcano and does not indicate "the volcano is likely to erupt anytime soon."

The USGS, and the Pacific Northwest Seismic Network at University of Washington, closely monitor ground deformation and seismicity at the volcano. This summer, they will also measure its released gases and gravity field, measurements that can be used to monitor subsurface magma and forecast eruptions.

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Evacuations near volcano in El Salvador
At least 1,000 people living near the Chaparrastique volcano have been evacuated as a precautionary measure after seismic activity increased at the volcano, Salvadoran civil protection authorities said Monday.

There was an explosion early Monday and the volcano then spewed reddish ash, officials said.

The Civil Protection Department said in a statement that an alert had been declared for the municipality of San Miguel, where the volcano is located. The city of San Miguel itself is 50 kilometres from the volcano. It is one of the largest cities in the Central American country.

The 2,129-metre volcano is about 145 kilometres east of San Salvador, the capital of El Salvador.

The volcano's last significant eruption was in 1976.

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Op donderdag 29 mei 2014 11:53 schreef Treehut362 het volgende:
De Bromo is de bekendste vulkaan op het eiland Java, Indonesië.
[ afbeelding ]

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Op donderdag 29 mei 2014 12:14 schreef Treehut362 het volgende:

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mijn vader is er geweest