From the Record Searchlight: USGS geologists map Lassen's volcanoes
Dr. Patrick Muffler describes himself, at 74, as "an overgrown Boy Scout." He's a rock hound who loves trekking in and around the lava fields, the steaming fumaroles, the boiling mud pots of Lassen National Park. He's a longtime field geologist who specializes in geothermal and volcanic activity. Like others in that field he has his war stories, like the time at Yellowstone he broke through a thin crust of grass and dirt into boiling water. When he took off his sock and boot, a good deal of his skin came with it.
As a scientist with the U.S. Geological Survey, Muffler has spent more than three decades studying the volcanic features of Lassen National Park. Much of what he's learned has just been published in the form of two detailed maps and an accompanying 110-page pamphlet, cowritten with a USGS colleague, Dr. Michael Clynne. The maps show seven separate volcanic centers at Lassen and use color coding to show the types of rock produced by eruptions from each of those volcanic centers.
One thing geologists have learned, Muffler said, is that the oldest rocks in the park go back about 3.5 million years. This means Lassen is a relative youngster in geologic time, the "frosting on the geologic cake," as Muffler puts it. After all, the oldest rocks on Earth go back 4 billion years.
It may be a relative newcomer, geologically speaking, but the Lassen volcanic region has had a lot of activity. The USGS scientists found evidence of more than 300 volcanic eruptions in those 3.5 million years.
It took the two geologists and their colleagues at USGS 35 years to produce the Lassen maps. "We've been on top of every bloody peak out there," Muffler said. Age-dating techniques developed in the 1990s enabled the scientists to calculate more precisely how long ago eruptions occurred at various locations in the park.
They've also been able to trace the outlines of the mother of all Lassen volcanoes, the massive Brokeoff Volcano, which dominated the Lassen skyline some 600,000 years ago the same way Mt. Shasta does in its own region today. Over the years Brokeoff was worn down by water and glacial erosion.
The park's current star volcano, Lassen Peak, last erupted in 1915, drawing attention to the volcanic region and spurring its designation the following year as a national park.
Lassen National Park offers "the most spectacular array of thermal features in the Cascade Range," according to the pamphlet that accompanies the new maps. Those spectacular features include the fumaroles, bubbling mud pots, and a boiling lake, Boiling Spring Lake — all evidence of the intense thermal activity just under the surface. But don't hold your breath for the next big volcanic event, another eruption of Lassen Peak. It isn't expected for another 7,000 years. The sky will be darkened by eruptions of ash from one of the park's cinder cones about 1,500 years from now, according to geologists' estimates.
The shifting of two huge tectonic plates, one under the Pacific Ocean floor and another under the North American continent, caused the fissures that have allowed hot lava to erupt through the Earth's surface at Lassen. There are very few fossils found at Lassen, by the way. Most of those prehistoric creatures have been burned to a crisp, skeletons and all, by hot lava flows.
Muffler officially retired from his Geologic Survey post eight years ago, but he still shows up at his office in Menlo Park every day as a volunteer. He's determined, he says, to "die with my boots on."
Recently, he was getting ready to strap on those boots once again, for a field trip to help PG&E assess the seismic hazards at one of its dams along the Pit River.
The Lassen volcanic maps and accompanying materials are available for $19.95 plus tax at the Lassen National Park Visitor's Centers at the Southwest entrance and at Manzanita Lake. Talks at Lassen National Park through Sept. 4 include "A Land Of Volcanoes," "Inside A Volcano At Sulphur Works," and "Inside A Volcano At Bumpass Hell." More info at www.nps.gov/lavo or 530-595-4480 ext. 0.
Learn more
FOR PURCHASE: The Lassen volcanic maps and accompanying materials are available for $19.95 plus tax at the Lassen National Park visitor centers at the southwest entrance and at Manzanita Lake.
IF YOU GO: Talks at Lassen National Park through Sept. 4 include “A Land Of Volcanoes,” “Inside A Volcano At Sulphur Works” and “Inside A Volcano At Bumpass Hell.”
Wednesday, August 31, 2011
Aug 27, 1883: Krakatoa blew up
So I'm a few days late with this. Sorry about that!
Krakatoa (Indonesian: Krakatau), is a volcanic island made of a'a lava in the Sunda Strait between the islands of Java and Sumatra in Indonesia. The name is used for the island group, the main island (also called Rakata), and the volcano as a whole. The island exploded on August 27, 1883, killing approximately 40,000 people, although some estimates put the death toll much higher. The explosion is considered to be the loudest sound ever heard in modern history, with reports of it being heard nearly 3,000 miles (4,800 km) from its point of origin. The shock wave from the explosion was recorded on barographs around the globe.
Historical significance
The best known eruption of Krakatoa culminated in a series of massive explosions on August 26–27, 1883, which was among the most violent volcanic events in modern and recorded history.
Etymology and orthography
The Sunda Strait
Although there are earlier descriptions of an island in the Sunda Strait with a "pointed mountain," the earliest mention of Krakatoa by name in the Western world was on a 1611 map by Lucas Janszoon Waghenaer, who labeled the island "Pulo Carcata." (Pulo is a form of pulau, the Indonesian word for "island"). About two dozen variants have been found, including Crackatouw, Cracatoa, and Krakatao (in an older Portuguese-based spelling). The first known appearance of the spelling Krakatau was by Wouter Schouten, who passed by "the high tree-covered island of Krakatau" in October 1658.[citation needed]
With a Volcanic Explosivity Index (VEI) of 6, the eruption was equivalent to 200 megatons of TNT (840 PJ) – about 13,000 times the nuclear yield of the Little Boy bomb (13 to 16 kt) that devastated Hiroshima, Japan, during World War II and four times the yield of the Tsar Bomba (50 Mt), the largest nuclear device ever detonated.
The 1883 eruption ejected approximately 21 km3 (5.0 cu mi) of rock, ash, and pumice.
The cataclysmic explosion was distinctly heard as far away as Perth in Western Australia, about 1,930 miles (3,110 km) away, and the island of Rodrigues near Mauritius, about 3,000 miles (5,000 km) away.
Near Krakatoa, according to official records, 165 villages and towns were destroyed and 132 seriously damaged, at least 21,007 (official toll) people died, and many thousands were injured by the eruption, mostly from the tsunamis that followed the explosion. The eruption destroyed two-thirds of the island of Krakatoa.
Eruptions at the volcano since 1927 have built a new island in the same location, named Anak Krakatau (which is Indonesian for "Child of Krakatoa"). This island currently has a radius of roughly 2 kilometres (1.2 mi) and a high point around 300 metres (980 ft) above sea level, growing 5 metres (16 ft) each year.
Krakatoa (Indonesian: Krakatau), is a volcanic island made of a'a lava in the Sunda Strait between the islands of Java and Sumatra in Indonesia. The name is used for the island group, the main island (also called Rakata), and the volcano as a whole. The island exploded on August 27, 1883, killing approximately 40,000 people, although some estimates put the death toll much higher. The explosion is considered to be the loudest sound ever heard in modern history, with reports of it being heard nearly 3,000 miles (4,800 km) from its point of origin. The shock wave from the explosion was recorded on barographs around the globe.
Historical significance
The best known eruption of Krakatoa culminated in a series of massive explosions on August 26–27, 1883, which was among the most violent volcanic events in modern and recorded history.
Etymology and orthography
The Sunda Strait
Although there are earlier descriptions of an island in the Sunda Strait with a "pointed mountain," the earliest mention of Krakatoa by name in the Western world was on a 1611 map by Lucas Janszoon Waghenaer, who labeled the island "Pulo Carcata." (Pulo is a form of pulau, the Indonesian word for "island"). About two dozen variants have been found, including Crackatouw, Cracatoa, and Krakatao (in an older Portuguese-based spelling). The first known appearance of the spelling Krakatau was by Wouter Schouten, who passed by "the high tree-covered island of Krakatau" in October 1658.[citation needed]
With a Volcanic Explosivity Index (VEI) of 6, the eruption was equivalent to 200 megatons of TNT (840 PJ) – about 13,000 times the nuclear yield of the Little Boy bomb (13 to 16 kt) that devastated Hiroshima, Japan, during World War II and four times the yield of the Tsar Bomba (50 Mt), the largest nuclear device ever detonated.
The 1883 eruption ejected approximately 21 km3 (5.0 cu mi) of rock, ash, and pumice.
The cataclysmic explosion was distinctly heard as far away as Perth in Western Australia, about 1,930 miles (3,110 km) away, and the island of Rodrigues near Mauritius, about 3,000 miles (5,000 km) away.
Near Krakatoa, according to official records, 165 villages and towns were destroyed and 132 seriously damaged, at least 21,007 (official toll) people died, and many thousands were injured by the eruption, mostly from the tsunamis that followed the explosion. The eruption destroyed two-thirds of the island of Krakatoa.
Eruptions at the volcano since 1927 have built a new island in the same location, named Anak Krakatau (which is Indonesian for "Child of Krakatoa"). This island currently has a radius of roughly 2 kilometres (1.2 mi) and a high point around 300 metres (980 ft) above sea level, growing 5 metres (16 ft) each year.
Tuesday, August 30, 2011
Indonesia: Mount Lokon activity declines as Marapi spews out white cloud
From DaijiWorld.com: Indonesia: Mount Lokon activity declines as Marapi spews out white cloud
SULAWESI, INDONESIA (BNO NEWS) -- Indonesia's Mount Lokon, located on the northern tip of the island of Sulawesi, showed declining activity on Monday after erupting several times last week, authorities said. Meanwhile, new activity has been reported at Mount Marapi.
Mount Lokon erupted as many as 12 times on Sunday, but it only erupted once on Monday at around 10.35 a.m. local time, spewing out volcanic materials about 250 meters (820 feet) high, volcano monitoring post staff member Jemmy Runtuwene told the Antara news agency.
On Sunday, monitoring staff recorded 65 deep volcanic earthquakes and 93 shallow earthquakes. During the first six hours of Monday, only seven earthquakes were registered in the area near the volcano.
Officials at the Volcanic and Geological Disaster Mitigation Center kept the volcano's alert status at Alert as of early Tuesday morning, but the alert could be lowered if activity continues to decline.
On August 17, Mount Lokon began to spew volcanic ash which fell as far away as the Kinilow I village and the Tinoor areas in North Tomohon sub district, which is a short distance from Lokon's crater.
Mount Lokon has shown constant volcanic activity since June, prompting authorities to raise its status to Alert on June 27 and Watch on July 10. A series of eruptions in mid-July forced at least 5,269 locals from the villages of Kinilow, Kelurahan Kinilow I and Kakaskasen 1 to evacuate the area.
While most residents returned to their homes later that month, some 222 people remain at temporary refugee camps because their homes are in Mound Lokon's red zone - 3 kilometers (1.86 miles) from its crater. After July's activity, Mount Lokon's alert level was lowered from Watch to Alert, and has remained at this level since.
Meanwhile, officials reported thick white smoke coming from Mount Marapi in West Sumatra on Sunday morning. Smoke could be seen gushing out of the crater and reaching up to 100 meters (328 feet).
Chief Warsono at the Volcanic and Geological Disaster Mitigation Center said Mount Marapi's alert level remains at level II, banning anyone from being closer than 3 kilometers (1.8 miles) to its crater.
Marapi, which stands 2,981 meters (9,780 feet) above sea level, became active in early August. It is located in the Tanahdatar sub-district, of West Sumatra and has been spewing volcanic ash with sulfuric smell up to 1,000 meters (3,280 feet) high.
Dozens of active volcanoes in Indonesia are part of the Pacific Ring of Fire, known for frequent earthquakes and volcanic eruptions. Next to Mount Lokon is its volcanic twin, Mount Empung, just 2.2 kilometers (1.3 miles) away.
One of Indonesia's most active volcanoes is Mount Merapi, which is located on the island of Java near Jogjakarta, the country's second-most visited area after Bali. Last year, more than 300 people were killed in a series of eruptions between October and November which also displaced over 300,000 people.
SULAWESI, INDONESIA (BNO NEWS) -- Indonesia's Mount Lokon, located on the northern tip of the island of Sulawesi, showed declining activity on Monday after erupting several times last week, authorities said. Meanwhile, new activity has been reported at Mount Marapi.
Mount Lokon erupted as many as 12 times on Sunday, but it only erupted once on Monday at around 10.35 a.m. local time, spewing out volcanic materials about 250 meters (820 feet) high, volcano monitoring post staff member Jemmy Runtuwene told the Antara news agency.
On Sunday, monitoring staff recorded 65 deep volcanic earthquakes and 93 shallow earthquakes. During the first six hours of Monday, only seven earthquakes were registered in the area near the volcano.
Officials at the Volcanic and Geological Disaster Mitigation Center kept the volcano's alert status at Alert as of early Tuesday morning, but the alert could be lowered if activity continues to decline.
On August 17, Mount Lokon began to spew volcanic ash which fell as far away as the Kinilow I village and the Tinoor areas in North Tomohon sub district, which is a short distance from Lokon's crater.
Mount Lokon has shown constant volcanic activity since June, prompting authorities to raise its status to Alert on June 27 and Watch on July 10. A series of eruptions in mid-July forced at least 5,269 locals from the villages of Kinilow, Kelurahan Kinilow I and Kakaskasen 1 to evacuate the area.
While most residents returned to their homes later that month, some 222 people remain at temporary refugee camps because their homes are in Mound Lokon's red zone - 3 kilometers (1.86 miles) from its crater. After July's activity, Mount Lokon's alert level was lowered from Watch to Alert, and has remained at this level since.
Meanwhile, officials reported thick white smoke coming from Mount Marapi in West Sumatra on Sunday morning. Smoke could be seen gushing out of the crater and reaching up to 100 meters (328 feet).
Chief Warsono at the Volcanic and Geological Disaster Mitigation Center said Mount Marapi's alert level remains at level II, banning anyone from being closer than 3 kilometers (1.8 miles) to its crater.
Marapi, which stands 2,981 meters (9,780 feet) above sea level, became active in early August. It is located in the Tanahdatar sub-district, of West Sumatra and has been spewing volcanic ash with sulfuric smell up to 1,000 meters (3,280 feet) high.
Dozens of active volcanoes in Indonesia are part of the Pacific Ring of Fire, known for frequent earthquakes and volcanic eruptions. Next to Mount Lokon is its volcanic twin, Mount Empung, just 2.2 kilometers (1.3 miles) away.
One of Indonesia's most active volcanoes is Mount Merapi, which is located on the island of Java near Jogjakarta, the country's second-most visited area after Bali. Last year, more than 300 people were killed in a series of eruptions between October and November which also displaced over 300,000 people.
Monday, August 29, 2011
Ocean Observatories Initiative Streams Live Video of Undersea Volcano
From Environmental Protection: Ocean Observatories Initiative Streams Live Video of Undersea Volcano
Last spring, a volcano erupted 425 kilometers (about 265 miles) off the Oregon coast and far below the surface, at Axial Seamount. No one was aware for months.
Now, the National Science Foundation's (NSF) Ocean Observatories Initiative (OOI) will survey the site and stream live video of the volcano. It's the first live video since the volcano spewed massive amounts of lava on April 6.
When NSF-funded Oregon State University geologist William Chadwick first discovered evidence of the April eruption on Axial in late July, he immediately communicated the information to a team of University of Washington (UW) scientists and engineers currently on an OOI expedition very near the recent eruption.
The team, aboard the research vessel Thomas G. Thompson, is conducting site surveys for the deployment of a sensor infrastructure that's part of OOI.
Surveying this site is just one example of the ways in which OOI will revolutionize the way oceanography is conducted. UW oceanographers John Delaney and Deborah Kelley are leading the expedition, known as VISIONS '11.
The submarine volcano is one of OOI's primary study sites. OOI, a multi-scale ocean observing system, will deploy sensors in the ocean and provide a networked system that will allow open access to data from the air-sea interface through the water column to the seafloor.
Scientists and engineers have been putting the finishing touches on the construction design phase of the cabled ocean observing system that forms a backbone of OOI.
This major component of the OOI program, with the formal name of the Regional Scale Nodes, is located off the Oregon and Washington coasts.
The Axial eruption has offered a rare opportunity to use this next-generation ocean-observing technology in innovative ways.
Investigating the seamount and its environs will allow the best decisions to be made on how to construct a long-term observatory at such active seafloor sites.
The crew on the Thompson is now using a host of modern seagoing research tools to examine the Axial site.
Their activities are focused in the short-term on using and producing new maps of the volcanic changes that have taken place since the eruption.
In another portion of the region off Oregon, other members of the OOI team on board the cable-laying ship TE Subcom Dependable are deploying and burying electro-optical cable as part of the current OOI installation activity.
"OOI is transforming our ability to study the global ocean," says Delaney. "We're fitting the Juan de Fuca Plate [off Oregon and Washington] and overlying ocean with myriad sensor arrays connected to a fiber optic-electrical network. This infrastructure will allow scientists to track changes taking place on a 24/7/365 basis for many decades."
Axial Seamount appears to be quiet at the moment, but viewers will see images of "frozen" eruptions with cooling lava flows blanketing the seafloor.
"We are excited to be working at Axial so soon after the latest eruption," said Kelley. "Using a remotely operated vehicle equipped with a high-definition underwater video camera, we are able to conduct surveys that will help determine the extent and amount of new lava flows, and assess the life forms that are already beginning to re-appear at the site."
It's a preview of the kinds of information OOI will enable researchers to collect.
OOI deployments will be on coastal, regional and global scales. OOI's planned operational timeframe is 25 years.
The data will be available to the public, educators and researchers, making oceanography possible for citizens and scholars who might never go to sea.
Sustained, time-series data provided by OOI will enable researchers to study complex, interlinked physical, chemical, biological and geological processes operating throughout the global ocean--processes such as those happening at Axial Seamount.
Last spring, a volcano erupted 425 kilometers (about 265 miles) off the Oregon coast and far below the surface, at Axial Seamount. No one was aware for months.
Now, the National Science Foundation's (NSF) Ocean Observatories Initiative (OOI) will survey the site and stream live video of the volcano. It's the first live video since the volcano spewed massive amounts of lava on April 6.
When NSF-funded Oregon State University geologist William Chadwick first discovered evidence of the April eruption on Axial in late July, he immediately communicated the information to a team of University of Washington (UW) scientists and engineers currently on an OOI expedition very near the recent eruption.
The team, aboard the research vessel Thomas G. Thompson, is conducting site surveys for the deployment of a sensor infrastructure that's part of OOI.
Surveying this site is just one example of the ways in which OOI will revolutionize the way oceanography is conducted. UW oceanographers John Delaney and Deborah Kelley are leading the expedition, known as VISIONS '11.
The submarine volcano is one of OOI's primary study sites. OOI, a multi-scale ocean observing system, will deploy sensors in the ocean and provide a networked system that will allow open access to data from the air-sea interface through the water column to the seafloor.
Scientists and engineers have been putting the finishing touches on the construction design phase of the cabled ocean observing system that forms a backbone of OOI.
This major component of the OOI program, with the formal name of the Regional Scale Nodes, is located off the Oregon and Washington coasts.
The Axial eruption has offered a rare opportunity to use this next-generation ocean-observing technology in innovative ways.
Investigating the seamount and its environs will allow the best decisions to be made on how to construct a long-term observatory at such active seafloor sites.
The crew on the Thompson is now using a host of modern seagoing research tools to examine the Axial site.
Their activities are focused in the short-term on using and producing new maps of the volcanic changes that have taken place since the eruption.
In another portion of the region off Oregon, other members of the OOI team on board the cable-laying ship TE Subcom Dependable are deploying and burying electro-optical cable as part of the current OOI installation activity.
"OOI is transforming our ability to study the global ocean," says Delaney. "We're fitting the Juan de Fuca Plate [off Oregon and Washington] and overlying ocean with myriad sensor arrays connected to a fiber optic-electrical network. This infrastructure will allow scientists to track changes taking place on a 24/7/365 basis for many decades."
Axial Seamount appears to be quiet at the moment, but viewers will see images of "frozen" eruptions with cooling lava flows blanketing the seafloor.
"We are excited to be working at Axial so soon after the latest eruption," said Kelley. "Using a remotely operated vehicle equipped with a high-definition underwater video camera, we are able to conduct surveys that will help determine the extent and amount of new lava flows, and assess the life forms that are already beginning to re-appear at the site."
It's a preview of the kinds of information OOI will enable researchers to collect.
OOI deployments will be on coastal, regional and global scales. OOI's planned operational timeframe is 25 years.
The data will be available to the public, educators and researchers, making oceanography possible for citizens and scholars who might never go to sea.
Sustained, time-series data provided by OOI will enable researchers to study complex, interlinked physical, chemical, biological and geological processes operating throughout the global ocean--processes such as those happening at Axial Seamount.
Repaving Jaggar Museum Path, Deck Begins at Hawaii Volcanoes NP
Old West News: Repaving Jaggar Museum Path, Deck Begins at Hawaii Volcanoes NP
Repaving of the exterior observation deck area and pathways adjacent to the Jaggar Museum at Hawaii Volcanoes National Park, part of the park's ongoing facility maintenance, is now underway.
The approximately 7,000 square foot repaving project will remove and replace the existing pavement in sections from the east side of the museum to the exterior museum bathrooms. Work began Aug. 22, 2011.
Continued access to the museum will be maintained throughout the project. However, not all of the entrances will be accessible at all times.
American with Disibility Act (ADA) museum access will be maintained throughout the project. A 10-person construction and interpretation crew will execute the work, direct pedestrian traffic and provide a safe environment for visitors.
Each phase of the project will see a portion of the area closed off by a safety barrier as old pavement is removed and new pavement is placed. An alternate temporary viewing area will be constructed to the west of the museum parking lot to alleviate pedestrian congestion.
Visitors are encouraged to use the Kilauea Overlook as an alternate viewing area for Halema'uma'u Crater. Construction is scheduled through September with a completion date mid-October, 2011.
Repaving will improve drainage, accommodate an expanded viewing area and extend the surface's life cycle by approximately 20 years. Every effort will be made to reduce the impact of the visitor experience, rangers said, but some inconvenience is, required to improve the park's visitor facilities for years to come.
The Thomas A. Jaggar Museum is located along Crater Rim Drive, three miles from the Kilauea Visitor Center. It is open from 8:30 a.m. to 7:30 p.m. daily. Built on the edge of Kilauea Caldera, visitors may enjoy spectacular views of the caldera and the main crater Halema`uma`u from this view point.
Prior to its opening as a museum on volcanology (the study of volcanoes and volcanic activity), the building housed offices for the U.S. Geological Survey's Hawaiian Volcano Observatory, the scientists who monitor the volcanoes in Hawaii. Working seismographs and displays on equipment used by the scientists are exhibits in the center.
Hawaii Volcanoes National Park is located on the island of Hawaii. The park displays the results of 70 million years of volcanism, migration, and evolution, processes that thrust a bare land from the sea and clothed it with unique ecosystems, and a distinct human culture.
The park highlights two of the world's most active volcanoes, and offers insights on the birth of the Hawaiian Islands and views of dramatic volcanic landscapes.
Repaving of the exterior observation deck area and pathways adjacent to the Jaggar Museum at Hawaii Volcanoes National Park, part of the park's ongoing facility maintenance, is now underway.
The approximately 7,000 square foot repaving project will remove and replace the existing pavement in sections from the east side of the museum to the exterior museum bathrooms. Work began Aug. 22, 2011.
Continued access to the museum will be maintained throughout the project. However, not all of the entrances will be accessible at all times.
American with Disibility Act (ADA) museum access will be maintained throughout the project. A 10-person construction and interpretation crew will execute the work, direct pedestrian traffic and provide a safe environment for visitors.
Each phase of the project will see a portion of the area closed off by a safety barrier as old pavement is removed and new pavement is placed. An alternate temporary viewing area will be constructed to the west of the museum parking lot to alleviate pedestrian congestion.
Visitors are encouraged to use the Kilauea Overlook as an alternate viewing area for Halema'uma'u Crater. Construction is scheduled through September with a completion date mid-October, 2011.
Repaving will improve drainage, accommodate an expanded viewing area and extend the surface's life cycle by approximately 20 years. Every effort will be made to reduce the impact of the visitor experience, rangers said, but some inconvenience is, required to improve the park's visitor facilities for years to come.
The Thomas A. Jaggar Museum is located along Crater Rim Drive, three miles from the Kilauea Visitor Center. It is open from 8:30 a.m. to 7:30 p.m. daily. Built on the edge of Kilauea Caldera, visitors may enjoy spectacular views of the caldera and the main crater Halema`uma`u from this view point.
Prior to its opening as a museum on volcanology (the study of volcanoes and volcanic activity), the building housed offices for the U.S. Geological Survey's Hawaiian Volcano Observatory, the scientists who monitor the volcanoes in Hawaii. Working seismographs and displays on equipment used by the scientists are exhibits in the center.
Hawaii Volcanoes National Park is located on the island of Hawaii. The park displays the results of 70 million years of volcanism, migration, and evolution, processes that thrust a bare land from the sea and clothed it with unique ecosystems, and a distinct human culture.
The park highlights two of the world's most active volcanoes, and offers insights on the birth of the Hawaiian Islands and views of dramatic volcanic landscapes.
Mount Etna's eruption intensifies in Italy
From the Seattle Times: Mount Etna's eruption intensifies in Italy
ROME —
Sicily's Mount Etna volcano is stepping up its eruption, spewing out ash and shooting lava into the air.
Italy's Civil Protection agency says the nation's geophysics and volcanology institute on Monday registered increased explosive activity by Etna, eight days after the latest eruption began.
The government agency says Etna started spewing out a significant amount of ash in a southeast direction early in the day but that the eruption tapered off in about two hours.
Etna has several inhabited villages on its slopes.
Eruptions are not infrequent, and Italian airliners sometimes have to alter their routes to avoid flying through ash cloud. The airport at Catania city near the volcano wasn't affected by the ash Monday.
ROME —
Sicily's Mount Etna volcano is stepping up its eruption, spewing out ash and shooting lava into the air.
Italy's Civil Protection agency says the nation's geophysics and volcanology institute on Monday registered increased explosive activity by Etna, eight days after the latest eruption began.
The government agency says Etna started spewing out a significant amount of ash in a southeast direction early in the day but that the eruption tapered off in about two hours.
Etna has several inhabited villages on its slopes.
Eruptions are not infrequent, and Italian airliners sometimes have to alter their routes to avoid flying through ash cloud. The airport at Catania city near the volcano wasn't affected by the ash Monday.
Thursday, August 25, 2011
Controlled burn helps native landscape
From Big Island News: Controlled burn helps native landscape
HAWAII VOLCANOES NATIONAL PARK, Hawaii: 130 acres burned at the bottom of Chain of Craters Road in the Hawaii Volcanoes National Park… all on purpose.
The controlled burn, taking place in Kealakomowaena, will regenerate the growth of native pili grass and other indigenous plant species, as well as maintain a cultural landscape once occupied by families living in the Kealakomo ahupua‘a.
There were no closures because of the burn, and park visitors and normal park activities were not be impacted.
Kealakomowaena is an island of vegetation, or kīpuka, spared by recent lava flows in the middle of the Kealakomo ahupua‘a. Officials say Hawaiians thrived in this coastal lowland area, growing sweet potatoes, harvesting fish and drying salt. House sites, trails, lava rock walls and agricultural plots are found throughout Kealakomowaena. The controlled burn was conducted by an eight-person fire crew, in a manner to help maintain the traditional landscape of the area.
The national park says controlled burning is part of a comprehensive restoration plan for the coastal lowland ecosystem at Hawai‘i Volcanoes National Park.
Here is the latest update on the Kilauea volcano eruption, courtesy the USGS Hawaiian Volcano Observatory, posted on August 24:
Activity Summary for past 24 hours: Inflation slowed. At the summit, the lava lake continued with drain-and-fill cycles. In the middle east rift zone, the lava level continued to rise within Pu`u `O`o crater but there was still no sign of activity from the west flank vents. Seismicity, other than the episodic tremor bursts associated with the fill-and-drain cycles, was low. Gas emissions remained elevated from summit and rift zone vents. All lava activity remained within Hawai`i Volcanoes National Park and posed no direct hazard to any developed areas.
Past 24 hours at Kilauea summit: The lava level continued to fluctuate in 15-20 minute-long fill-and-drain cycles, each fill bringing the lava level to a high point below the inner ledge (the ledge is 75 m or 250 ft below Halema`uma`u Crater floor); lava fills the vent cavity bottom from the southeast and also drains toward the same place. The most recent (preliminary) sulfur dioxide emission rate measurement was 500 tonnes/day on August 19, 2011. Small amounts of ash-sized tephra, including fresh spatter bits, continued to be wafted within the plume and deposited on nearby surfaces.
The summit tiltmeter network recorded continued weak inflation. The summit GPS network recorded extension since Aug. 17. Seismic tremor levels were episodically high during the draining part of fill-and-drain cycles. Sixteen earthquakes were strong enough to be located within Kilauea volcano – two within the upper and middle east rift zone and fourteen on south flank faults (including a flurry of 9 earthquakes that occurred between 9:15-10:40 pm last night.
Seismic energy from the Peru magnitude-6.8 earthquake was recorded on our seismometers at 7:58 am HST this morning, about 12 minutes after it occurred; The Pacific Tsunami Warning Center has issued an Information Bulletin saying “A DESTRUCTIVE TSUNAMI WAS NOT GENERATED BASED ON EARTHQUAKE AND HISTORICAL TSUNAMI DATA.”
Background: The summit lava lake is deep within a ~150 m (500 ft) diameter near-vertical cylindrical vent inset within the east wall and floor of Halema`uma`u Crater and its level fluctuates from about 70 m to more than 150 m (out of sight) below the floor of Halema`uma`u Crater. The vent has been mostly active since opening with a small explosive event on March 19, 2008.
Past 24 hours at the middle east rift zone vents: Lava continued to cover more of the floor and slowly fill Pu`u `O`o Crater. There was no sign of lava activity from the west flank vents.
The tiltmeter on the north flank of Pu`u `O`o Cone continued to record weak inflation. GPS receivers on opposite sides of Pu`u `O`o cone recorded a gentle transition to very weak extension. Seismic tremor levels were low. The most recent (preliminary) sulfur dioxide emission rate measurement was 200 tonnes/day on August 19, 2011, from all east rift zone sources.
Background: The eruption of Kilauea’s middle east rift zone started with a fissure eruption on January 3, 1983, and has continued with few interruptions through Pu`u `O`o Crater or vents within a few kilometers to the east or west. In early August, the crater floor collapsed to a depth of about 75 m (245 ft) below the east rim as lava burst from vents on the west flank of Pu`u `O`o cone. A DI tilt event a few days later cut off supply to Pu`u `O`o and the west flank vents; lava reappeared in Pu`u `O`o Crater on August 21st.
Past 24 hours within the lower east rift zone: There were two earthquakes recorded in this area with magnitudes less than 1.5.
Background: Residents reported several felt earthquakes in this area between August 4th and 15th.
HAWAII VOLCANOES NATIONAL PARK, Hawaii: 130 acres burned at the bottom of Chain of Craters Road in the Hawaii Volcanoes National Park… all on purpose.
The controlled burn, taking place in Kealakomowaena, will regenerate the growth of native pili grass and other indigenous plant species, as well as maintain a cultural landscape once occupied by families living in the Kealakomo ahupua‘a.
There were no closures because of the burn, and park visitors and normal park activities were not be impacted.
Kealakomowaena is an island of vegetation, or kīpuka, spared by recent lava flows in the middle of the Kealakomo ahupua‘a. Officials say Hawaiians thrived in this coastal lowland area, growing sweet potatoes, harvesting fish and drying salt. House sites, trails, lava rock walls and agricultural plots are found throughout Kealakomowaena. The controlled burn was conducted by an eight-person fire crew, in a manner to help maintain the traditional landscape of the area.
The national park says controlled burning is part of a comprehensive restoration plan for the coastal lowland ecosystem at Hawai‘i Volcanoes National Park.
Here is the latest update on the Kilauea volcano eruption, courtesy the USGS Hawaiian Volcano Observatory, posted on August 24:
Activity Summary for past 24 hours: Inflation slowed. At the summit, the lava lake continued with drain-and-fill cycles. In the middle east rift zone, the lava level continued to rise within Pu`u `O`o crater but there was still no sign of activity from the west flank vents. Seismicity, other than the episodic tremor bursts associated with the fill-and-drain cycles, was low. Gas emissions remained elevated from summit and rift zone vents. All lava activity remained within Hawai`i Volcanoes National Park and posed no direct hazard to any developed areas.
Past 24 hours at Kilauea summit: The lava level continued to fluctuate in 15-20 minute-long fill-and-drain cycles, each fill bringing the lava level to a high point below the inner ledge (the ledge is 75 m or 250 ft below Halema`uma`u Crater floor); lava fills the vent cavity bottom from the southeast and also drains toward the same place. The most recent (preliminary) sulfur dioxide emission rate measurement was 500 tonnes/day on August 19, 2011. Small amounts of ash-sized tephra, including fresh spatter bits, continued to be wafted within the plume and deposited on nearby surfaces.
The summit tiltmeter network recorded continued weak inflation. The summit GPS network recorded extension since Aug. 17. Seismic tremor levels were episodically high during the draining part of fill-and-drain cycles. Sixteen earthquakes were strong enough to be located within Kilauea volcano – two within the upper and middle east rift zone and fourteen on south flank faults (including a flurry of 9 earthquakes that occurred between 9:15-10:40 pm last night.
Seismic energy from the Peru magnitude-6.8 earthquake was recorded on our seismometers at 7:58 am HST this morning, about 12 minutes after it occurred; The Pacific Tsunami Warning Center has issued an Information Bulletin saying “A DESTRUCTIVE TSUNAMI WAS NOT GENERATED BASED ON EARTHQUAKE AND HISTORICAL TSUNAMI DATA.”
Background: The summit lava lake is deep within a ~150 m (500 ft) diameter near-vertical cylindrical vent inset within the east wall and floor of Halema`uma`u Crater and its level fluctuates from about 70 m to more than 150 m (out of sight) below the floor of Halema`uma`u Crater. The vent has been mostly active since opening with a small explosive event on March 19, 2008.
Past 24 hours at the middle east rift zone vents: Lava continued to cover more of the floor and slowly fill Pu`u `O`o Crater. There was no sign of lava activity from the west flank vents.
The tiltmeter on the north flank of Pu`u `O`o Cone continued to record weak inflation. GPS receivers on opposite sides of Pu`u `O`o cone recorded a gentle transition to very weak extension. Seismic tremor levels were low. The most recent (preliminary) sulfur dioxide emission rate measurement was 200 tonnes/day on August 19, 2011, from all east rift zone sources.
Background: The eruption of Kilauea’s middle east rift zone started with a fissure eruption on January 3, 1983, and has continued with few interruptions through Pu`u `O`o Crater or vents within a few kilometers to the east or west. In early August, the crater floor collapsed to a depth of about 75 m (245 ft) below the east rim as lava burst from vents on the west flank of Pu`u `O`o cone. A DI tilt event a few days later cut off supply to Pu`u `O`o and the west flank vents; lava reappeared in Pu`u `O`o Crater on August 21st.
Past 24 hours within the lower east rift zone: There were two earthquakes recorded in this area with magnitudes less than 1.5.
Background: Residents reported several felt earthquakes in this area between August 4th and 15th.
Teacher died in brother's arms after volcano fall
Not really news about a volcano, but a sad story which I share to also illustrate that people can walk up and down volcanoes - but that there are risks involved, not all of them related to lava or steam.
Teacher died in brother's arms after volcano fall
SIBLINGS of an Irish student teacher, who was killed after falling on a volcano hiking trip, have arrived in Nicaragua to repatriate his body.
Michael McLean (26) died in his younger brother Conor's arms on Sunday after falling and hitting his head during a guided expedition.
Two of his siblings, Roisin and Martin travelled to South America yesterday to bring his remains home to the Fruithill area of west Belfast.
They are expected back in the North by tomorrow at the earliest and a funeral should take place early next week, a family friend told the Herald.
Michael, an engineer, had re-trained as a geography teacher in Liverpool.
He had just graduated and hoped to take six months off before starting his new career.
He flew over to Boston a month ago where he met his brother Conor (24), who was also taking a year out.
The pair planned to travel across Central and South America before heading back to Northern Ireland for Christmas.
MISSED
However, their plans were tragically cut short when he slipped while hiking up a volcano, and fell from a height.
It is understood he hit his head during the fall and suffered fatal injuries. A post mortem took place this week.
Michael's parents Laurence and Marie, and his five siblings Patricia, Roisin, Louise, Conor and Martin said yesterday that he had been "a much loved son, brother, uncle and friend to many".
Marie added: "He was a very popular figure and will be sadly missed by a huge number of people. The circumstances of his death overseas are difficult for the family.
"We hope to have his body home as quickly as possible and in the meantime we would respectfully ask for privacy."
Teacher died in brother's arms after volcano fall
SIBLINGS of an Irish student teacher, who was killed after falling on a volcano hiking trip, have arrived in Nicaragua to repatriate his body.
Michael McLean (26) died in his younger brother Conor's arms on Sunday after falling and hitting his head during a guided expedition.
Two of his siblings, Roisin and Martin travelled to South America yesterday to bring his remains home to the Fruithill area of west Belfast.
They are expected back in the North by tomorrow at the earliest and a funeral should take place early next week, a family friend told the Herald.
Michael, an engineer, had re-trained as a geography teacher in Liverpool.
He had just graduated and hoped to take six months off before starting his new career.
He flew over to Boston a month ago where he met his brother Conor (24), who was also taking a year out.
The pair planned to travel across Central and South America before heading back to Northern Ireland for Christmas.
MISSED
However, their plans were tragically cut short when he slipped while hiking up a volcano, and fell from a height.
It is understood he hit his head during the fall and suffered fatal injuries. A post mortem took place this week.
Michael's parents Laurence and Marie, and his five siblings Patricia, Roisin, Louise, Conor and Martin said yesterday that he had been "a much loved son, brother, uncle and friend to many".
Marie added: "He was a very popular figure and will be sadly missed by a huge number of people. The circumstances of his death overseas are difficult for the family.
"We hope to have his body home as quickly as possible and in the meantime we would respectfully ask for privacy."
Wednesday, August 24, 2011
Amphitheater at St. Helens crater nearing completion
Seattle TImes: Amphitheater at St. Helens crater nearing completion
MOUNT ST. HELENS — Work on the amphitheater at Johnston Ridge, a project first conceived of nearly two decades ago, is coming down the homestretch, but officials don't know if it will be ready in time for this tourist season.
That, as with most things at Mount St. Helens, will be up to Mother Nature.
Cut into a slope directly north of the volcano, the outdoor amphitheater will give tourists the opportunity to hear presentations about the mountain's eruptions with the peak looming directly in front of them. Speakers will appear to speak from the very maw of the volcano's crater.
Completion of the amphitheater will greatly enhance visits to Johnston Ridge Observatory, according to U.S. Forest Service officials.
Modeled after ancient Greek theaters, the semicircular facility will allow rangers to give longer, more detailed talks than the 10- to 20-minute presentations now given at the Johnston Ridge plaza, said Todd Cullings, assistant manager of the observatory.
"It is a really stunning view," Cullings said Monday. "This also will provide a quieter spot. (The observatory) is a very busy site. It is away from the plaza deck and off to the side. It will be a place for people to sit and contemplate. It is also one of the few spots where there are shattered tree stumps and blown-down trees right in the foreground."
The Johnston Ridge Observatory's interpretive message focuses on the volcano, its crater and the eruption on May 18, 1980, that killed 57 people and laid waste an expanse of forest. A curtain in its movie theater parts to reveal a view of the volcano through a window after films are shown. The amphitheater, however, will put visitors right in the landscape as they're learning about it, said Peter Frenzen, scientist in charge of the 110,000-acre Mount St. Helens National Volcanic Monument.
"The story of Mount St. Helens is much more than the crater and the eruption. It is the landscape and the recreation of the (damaged) landscape. You need to be outside. What the visitors gain is to be actually looking at the landscape and being part of the landscape while they are hearing and learning about it. It is pretty amazing."
The amphitheater will hold from 100 to 150 people "depending on how you pack them in," Frenzen said.
Forest Service officials first conceived of the amphitheater when planning the Johnston Ridge Observatory some 20 years ago, but funding for it was cut and the observatory opened in 1997 without it. It's part of about $600,000 in improvements funded this year at the observatory.
The amphitheater will likely be used for other types of presentations — such as poetry readings, musical performances and artistic presentations — on a case-by-case basis as long as they are compatible with other uses and the purpose of the observatory, Frenzen said.
Workers are expected to pour the last of the concrete for the amphitheater this week, but whether work is complete in time for presentations this fall will depend on the weather, Cullings said.
The observatory, which is located at more than 4,000 feet above sea level, closes every winter because of snowfall.
MOUNT ST. HELENS — Work on the amphitheater at Johnston Ridge, a project first conceived of nearly two decades ago, is coming down the homestretch, but officials don't know if it will be ready in time for this tourist season.
That, as with most things at Mount St. Helens, will be up to Mother Nature.
Cut into a slope directly north of the volcano, the outdoor amphitheater will give tourists the opportunity to hear presentations about the mountain's eruptions with the peak looming directly in front of them. Speakers will appear to speak from the very maw of the volcano's crater.
Completion of the amphitheater will greatly enhance visits to Johnston Ridge Observatory, according to U.S. Forest Service officials.
Modeled after ancient Greek theaters, the semicircular facility will allow rangers to give longer, more detailed talks than the 10- to 20-minute presentations now given at the Johnston Ridge plaza, said Todd Cullings, assistant manager of the observatory.
"It is a really stunning view," Cullings said Monday. "This also will provide a quieter spot. (The observatory) is a very busy site. It is away from the plaza deck and off to the side. It will be a place for people to sit and contemplate. It is also one of the few spots where there are shattered tree stumps and blown-down trees right in the foreground."
The Johnston Ridge Observatory's interpretive message focuses on the volcano, its crater and the eruption on May 18, 1980, that killed 57 people and laid waste an expanse of forest. A curtain in its movie theater parts to reveal a view of the volcano through a window after films are shown. The amphitheater, however, will put visitors right in the landscape as they're learning about it, said Peter Frenzen, scientist in charge of the 110,000-acre Mount St. Helens National Volcanic Monument.
"The story of Mount St. Helens is much more than the crater and the eruption. It is the landscape and the recreation of the (damaged) landscape. You need to be outside. What the visitors gain is to be actually looking at the landscape and being part of the landscape while they are hearing and learning about it. It is pretty amazing."
The amphitheater will hold from 100 to 150 people "depending on how you pack them in," Frenzen said.
Forest Service officials first conceived of the amphitheater when planning the Johnston Ridge Observatory some 20 years ago, but funding for it was cut and the observatory opened in 1997 without it. It's part of about $600,000 in improvements funded this year at the observatory.
The amphitheater will likely be used for other types of presentations — such as poetry readings, musical performances and artistic presentations — on a case-by-case basis as long as they are compatible with other uses and the purpose of the observatory, Frenzen said.
Workers are expected to pour the last of the concrete for the amphitheater this week, but whether work is complete in time for presentations this fall will depend on the weather, Cullings said.
The observatory, which is located at more than 4,000 feet above sea level, closes every winter because of snowfall.
Monday, August 22, 2011
Watch Live Feed from Underwater Volcano Today
From Our Amazing Planet: Watch Live Feed from Underwater Volcano Today
(Must be viewed via computer:
Catch some volcano action live from the seafloor today, as scientists, with the help of a deep-diving robot, explore the aftermath of a recent eruption at the Axial Seamount, an underwater volcano roughly 250 miles (400 kilometers) off the Oregon coast.
Researchers aboard the research vessel Thomas G. Thompson are streaming live footage of the undersea volcano, sending back images of blobby, hardened lava and the occasional strange sea creature, captured by a camera-equipped remotely operated vehicle (ROV).
The scientists are inspecting cables that have been laid along the seafloor — part of a larger observing system designed to send real-time data on ocean conditions to scientists back on land.
Scientists recently discovered that the Axial Volcano erupted in early April, spewing forth a layer of lava more than 12 feet (4 meters) thick in some places, and opening up new vents that belch forth a cloudy stew of hot water and microbes from deep inside the Earth.
Researchers had been monitoring the volcano since 1998, when it last erupted, and suspected the mountain would erupt sometime before 2014.
The Axial Volcano rises 3,000 feet (900 m) above the seafloor, and is the most active of a string of volcanoes along the Juan de Fuca Ridge, a plate boundary where the seafloor is slowly pulling apart.
Watch the live feed here. http://interactiveoceans.washington.edu/visions11/live
And an article from March 31:
Deep-sea volcanoes can explode instead of just oozing, scientists now confirm.
The new proof — higher-than-expected levels of carbon dioxide in the magma from a volcano off the coast of Oregon —suggests the volcanoes may play a greater role in global climate than thought.
Of all the volcanic activity on Earth, 75 to 80 percent of it takes place at deep-sea ridges in the middle of the oceans. Most of these volcanoes apparently spew out huge volumes of lava instead of erupting explosively, as many volcanoes on land do.
It is a high level of gas trapped in a volcano's magma that normally fuels explosive volcanic bursts. This level has long been thought to be low at mid-ocean ridges; moreover, potential undersea explosions would be suppressed by the crushing pressure from the surrounding water.
However, based on volcanic ash found at certain sites, geologists have speculated over the last decade that explosive eruptions do take place in deep-sea volcanoes. Now researchers say they have proof.
A team of scientists used ion beams to analyze the composition of materials recovered from ash deposits on Axial Volcano, on the Juan de Fuca Ridge off the coast of Oregon. Trapped within crystals from the deposits were droplets of magma containing very high levels of carbon dioxide. These droplets revealed that the magma was indeed rich in gas, at concentrations high enough to generate bubbles in the molten rock for explosive underwater eruptions.
"Direct evidence for high carbon dioxide concentrations in a mid-ocean-ridge volcano was unexpected and surprising," researcher Christoph Helo, a volcanologist at McGill University in Montreal, told OurAmazingPlanet.
These findings suggest the amount of the global-warming gas carbon dioxide that is released from the deeper mantle into the Earth's atmosphere at mid-ocean ridges falls within the higher end of past estimates, nearly 10 times more than the lowest end. That could have key implications for climate change.
Still, Helo said, volcanic carbon dioxide, unlike man-made emissions, "is not a variable that has undergone drastic changes within the past century."
The scientists detailed their findings online March 13 in the journal Nature Geoscience.
(Must be viewed via computer:
Catch some volcano action live from the seafloor today, as scientists, with the help of a deep-diving robot, explore the aftermath of a recent eruption at the Axial Seamount, an underwater volcano roughly 250 miles (400 kilometers) off the Oregon coast.
Researchers aboard the research vessel Thomas G. Thompson are streaming live footage of the undersea volcano, sending back images of blobby, hardened lava and the occasional strange sea creature, captured by a camera-equipped remotely operated vehicle (ROV).
The scientists are inspecting cables that have been laid along the seafloor — part of a larger observing system designed to send real-time data on ocean conditions to scientists back on land.
Scientists recently discovered that the Axial Volcano erupted in early April, spewing forth a layer of lava more than 12 feet (4 meters) thick in some places, and opening up new vents that belch forth a cloudy stew of hot water and microbes from deep inside the Earth.
Researchers had been monitoring the volcano since 1998, when it last erupted, and suspected the mountain would erupt sometime before 2014.
The Axial Volcano rises 3,000 feet (900 m) above the seafloor, and is the most active of a string of volcanoes along the Juan de Fuca Ridge, a plate boundary where the seafloor is slowly pulling apart.
Watch the live feed here. http://interactiveoceans.washington.edu/visions11/live
And an article from March 31:
Deep-sea volcanoes can explode instead of just oozing, scientists now confirm.
The new proof — higher-than-expected levels of carbon dioxide in the magma from a volcano off the coast of Oregon —suggests the volcanoes may play a greater role in global climate than thought.
Of all the volcanic activity on Earth, 75 to 80 percent of it takes place at deep-sea ridges in the middle of the oceans. Most of these volcanoes apparently spew out huge volumes of lava instead of erupting explosively, as many volcanoes on land do.
It is a high level of gas trapped in a volcano's magma that normally fuels explosive volcanic bursts. This level has long been thought to be low at mid-ocean ridges; moreover, potential undersea explosions would be suppressed by the crushing pressure from the surrounding water.
However, based on volcanic ash found at certain sites, geologists have speculated over the last decade that explosive eruptions do take place in deep-sea volcanoes. Now researchers say they have proof.
A team of scientists used ion beams to analyze the composition of materials recovered from ash deposits on Axial Volcano, on the Juan de Fuca Ridge off the coast of Oregon. Trapped within crystals from the deposits were droplets of magma containing very high levels of carbon dioxide. These droplets revealed that the magma was indeed rich in gas, at concentrations high enough to generate bubbles in the molten rock for explosive underwater eruptions.
"Direct evidence for high carbon dioxide concentrations in a mid-ocean-ridge volcano was unexpected and surprising," researcher Christoph Helo, a volcanologist at McGill University in Montreal, told OurAmazingPlanet.
These findings suggest the amount of the global-warming gas carbon dioxide that is released from the deeper mantle into the Earth's atmosphere at mid-ocean ridges falls within the higher end of past estimates, nearly 10 times more than the lowest end. That could have key implications for climate change.
Still, Helo said, volcanic carbon dioxide, unlike man-made emissions, "is not a variable that has undergone drastic changes within the past century."
The scientists detailed their findings online March 13 in the journal Nature Geoscience.
Friday, August 19, 2011
Mount Vesuvius - a history
From Wikipedia:
Mount Vesuvius (Italian: Monte Vesuvio, Latin: Mons Vesuvius) is a stratovolcano on the Bay of Naples, Italy, about 9 kilometres (5.6 mi) east of Naples and a short distance from the shore. It is the only volcano on the European mainland to have erupted within the last hundred years, although it is not currently erupting. The two other major active volcanoes in Italy, Etna and Stromboli, are located on island of Sicily.
Mount Vesuvius is best known for its eruption in AD 79 that led to the burying and destruction of the Roman cities of Pompeii and Herculaneum. They were never rebuilt, although surviving townspeople and probably looters did undertake extensive salvage work after the destructions. The towns' locations were eventually forgotten until their accidental rediscovery in the 18th century.
The eruption also changed the course of the Sarno River and raised the sea beach, so that Pompeii was now neither on the river nor adjacent to the coast. Vesuvius itself underwent major changes – its slopes were denuded of vegetation and its summit changed considerably due to the force of the eruption. Vesuvius has erupted many times since and is today regarded as one of the most dangerous volcanoes in the world because of the population of 3,000,000 people living nearby and its tendency towards explosive (Plinian) eruptions. It is the most densely populated volcanic region in the world.
Physical Appearance
Vesuvius is a distinctive "humpbacked" mountain, consisting of a large cone (Gran Cono) partially encircled by the steep rim of a summit caldera caused by the collapse of an earlier and originally much higher structure called Monte Somma.[10] The Gran Cono was produced during the eruption of AD 79. For this reason, the volcano is also called Somma-Vesuvius or Somma-Vesuvio.
The caldera started forming during an eruption around 17,000 (or 18,300[11]) years ago[12][13] and was enlarged by later paroxysmal eruptions[14] ending in the one of AD 79. This structure has given its name to the term "somma volcano", which describes any volcano with a summit caldera surrounding a newer cone.[15]
The height of the main cone has been constantly changed by eruptions but is 1,281 m (4,202 ft) at present. Monte Somma is 1,149 m (3,770 ft) high, separated from the main cone by the valley of Atrio di Cavallo, which is some 3 miles (5 km) long. The slopes of the mountain are scarred by lava flows but are heavily vegetated, with scrub and forest at higher altitudes and vineyards lower down. Vesuvius is still regarded as an active volcano, although its current activity produces little more than steam from vents at the bottom of the crater. Vesuvius is a stratovolcano at the convergent boundary where the African Plate is being subducted beneath the Eurasian Plate. Layers of lava, scoria, volcanic ash, and pumice make up the mountain. Their mineralogy is variable, but generally silica-undersaturated and rich in potassium, with phonolite produced in the more explosive eruptions.[16]
Formation
Vesuvius was formed as a result of the collision of two tectonic plates, the African and the Eurasian. The former was pushed beneath the latter, deeper into the earth. As the water-saturated sediments of the oceanic African plate were pushed to hotter depths in the earth, the water boiled off and caused the melting point of the upper mantle to drop enough to create partial melting of the rocks. Because magma is less dense than the solid rock around it, it was pushed upward. Finding a weak place at the Earth's surface it broke through, producing the volcano.
The volcano is one of several which form the Campanian volcanic arc. Others include Campi Flegrei, a large caldera a few kilometres to the north west, Mount Epomeo, 20 kilometres (12 mi) to the west on the island of Ischia, and several undersea volcanoes to the south. The arc forms the southern end of a larger chain of volcanoes produced by the subduction process described above, which extends northwest along the length of Italy as far as Monte Amiata in Southern Tuscany. Vesuvius is the only one to have erupted within recent history, although some of the others have erupted within the last few hundred years. Many are either extinct or have not erupted for tens of thousands of years.
Eruptions in the 20th century
The eruption of 1906 killed over 100 people and ejected the most lava ever recorded from a Vesuvian eruption.
The last major eruption was in March 1944. This eruption destroyed the villages of San Sebastiano al Vesuvio, Massa di Somma, Ottaviano, and part of San Giorgio a Cremano. From 18 March to 23 March 1944, lava flows appeared within the rim. There were outflows. Small explosions then occurred until the major explosion took place on 18 March 1944.
At the time of the eruption, the United States Army Air Force (USAAF) 340th Bombardment Group was based at Pompeii Airfield near Terzigno, Italy, just a few kilometers from the eastern base of the mountain. The tephra and hot ash damaged the fabric control surfaces, the engines, the Plexiglass windshields and the gun turrets of the 340th's B-25 Mitchell medium bombers. Estimates ranged from 78 to 88 aircraft destroyed.
The eruption could be seen from Naples. Different perspectives and the damage caused to the local villages were recorded by USAAF photographers and other personnel based nearer to the volcano.
Mount Vesuvius (Italian: Monte Vesuvio, Latin: Mons Vesuvius) is a stratovolcano on the Bay of Naples, Italy, about 9 kilometres (5.6 mi) east of Naples and a short distance from the shore. It is the only volcano on the European mainland to have erupted within the last hundred years, although it is not currently erupting. The two other major active volcanoes in Italy, Etna and Stromboli, are located on island of Sicily.
Mount Vesuvius is best known for its eruption in AD 79 that led to the burying and destruction of the Roman cities of Pompeii and Herculaneum. They were never rebuilt, although surviving townspeople and probably looters did undertake extensive salvage work after the destructions. The towns' locations were eventually forgotten until their accidental rediscovery in the 18th century.
The eruption also changed the course of the Sarno River and raised the sea beach, so that Pompeii was now neither on the river nor adjacent to the coast. Vesuvius itself underwent major changes – its slopes were denuded of vegetation and its summit changed considerably due to the force of the eruption. Vesuvius has erupted many times since and is today regarded as one of the most dangerous volcanoes in the world because of the population of 3,000,000 people living nearby and its tendency towards explosive (Plinian) eruptions. It is the most densely populated volcanic region in the world.
Physical Appearance
Vesuvius is a distinctive "humpbacked" mountain, consisting of a large cone (Gran Cono) partially encircled by the steep rim of a summit caldera caused by the collapse of an earlier and originally much higher structure called Monte Somma.[10] The Gran Cono was produced during the eruption of AD 79. For this reason, the volcano is also called Somma-Vesuvius or Somma-Vesuvio.
The caldera started forming during an eruption around 17,000 (or 18,300[11]) years ago[12][13] and was enlarged by later paroxysmal eruptions[14] ending in the one of AD 79. This structure has given its name to the term "somma volcano", which describes any volcano with a summit caldera surrounding a newer cone.[15]
The height of the main cone has been constantly changed by eruptions but is 1,281 m (4,202 ft) at present. Monte Somma is 1,149 m (3,770 ft) high, separated from the main cone by the valley of Atrio di Cavallo, which is some 3 miles (5 km) long. The slopes of the mountain are scarred by lava flows but are heavily vegetated, with scrub and forest at higher altitudes and vineyards lower down. Vesuvius is still regarded as an active volcano, although its current activity produces little more than steam from vents at the bottom of the crater. Vesuvius is a stratovolcano at the convergent boundary where the African Plate is being subducted beneath the Eurasian Plate. Layers of lava, scoria, volcanic ash, and pumice make up the mountain. Their mineralogy is variable, but generally silica-undersaturated and rich in potassium, with phonolite produced in the more explosive eruptions.[16]
Formation
Vesuvius was formed as a result of the collision of two tectonic plates, the African and the Eurasian. The former was pushed beneath the latter, deeper into the earth. As the water-saturated sediments of the oceanic African plate were pushed to hotter depths in the earth, the water boiled off and caused the melting point of the upper mantle to drop enough to create partial melting of the rocks. Because magma is less dense than the solid rock around it, it was pushed upward. Finding a weak place at the Earth's surface it broke through, producing the volcano.
The volcano is one of several which form the Campanian volcanic arc. Others include Campi Flegrei, a large caldera a few kilometres to the north west, Mount Epomeo, 20 kilometres (12 mi) to the west on the island of Ischia, and several undersea volcanoes to the south. The arc forms the southern end of a larger chain of volcanoes produced by the subduction process described above, which extends northwest along the length of Italy as far as Monte Amiata in Southern Tuscany. Vesuvius is the only one to have erupted within recent history, although some of the others have erupted within the last few hundred years. Many are either extinct or have not erupted for tens of thousands of years.
Eruptions in the 20th century
The eruption of 1906 killed over 100 people and ejected the most lava ever recorded from a Vesuvian eruption.
The last major eruption was in March 1944. This eruption destroyed the villages of San Sebastiano al Vesuvio, Massa di Somma, Ottaviano, and part of San Giorgio a Cremano. From 18 March to 23 March 1944, lava flows appeared within the rim. There were outflows. Small explosions then occurred until the major explosion took place on 18 March 1944.
At the time of the eruption, the United States Army Air Force (USAAF) 340th Bombardment Group was based at Pompeii Airfield near Terzigno, Italy, just a few kilometers from the eastern base of the mountain. The tephra and hot ash damaged the fabric control surfaces, the engines, the Plexiglass windshields and the gun turrets of the 340th's B-25 Mitchell medium bombers. Estimates ranged from 78 to 88 aircraft destroyed.
The eruption could be seen from Naples. Different perspectives and the damage caused to the local villages were recorded by USAAF photographers and other personnel based nearer to the volcano.
Old News: Mount Vesuvius erupts in 1906
There's not been a lot of volcano activity recently, so let's check what happened on April 10, 1906.
From the New York Times. (Just the first paragraph, as the rest of the article is inaccessible.)
VOLCANO VICTIMS MAY NUMBER 500; 200 Dead in San Giuseppe District Alone. CHURCHES CRUSH PEOPLE Weight of Ashes on Roofs Destroys Structures. ITALY'S KING IN PERIL His Auto Nearly Overwhelmed by Cinders -- 150,000 Refugees -- Lava Streams Cooling.
NAPLES, April 9. -- Reports of fatalities consequent upon the eruption of Mount Vesuvius are coming in. According to information received late to-night, probably 500 lives were lost. More than 200 perished in the District of San Giuseppe, while from the ruins of a church which collapsed, owing to the weight of ashes on the roof, forty-nine bodies were extricated.
Wednesday, August 17, 2011
Surprise! Underwater volcano has erupted
From MSNBC Aug 9, 2011: Surprise! Underwater volcano has erupted
An undersea volcano has erupted off the coast of Oregon, spewing forth a layer of lava more than 12 feet thick in some places, and opening up deep vents that belch forth a cloudy stew of hot water and microbes from deep inside the Earth.
Scientists uncovered evidence of the early April eruption on a routine expedition in late July to the Axial Seamount, an underwater volcano that stands 250 miles off the coast of Oregon.
The discovery came as a surprise, as researchers attempted to recover instruments they'd left behind to monitor the peak a year earlier. When the researchers hefted a seafaring robotic vehicle overboard to fetch the instruments, the feed from the onboard camera sent back images of an alien seafloor landscape.
"At first we were really confused, and thought we were in the wrong place," said Bill Chadwick, a geologist with Oregon State University. "Finally we figured out we were in the right place but the whole seafloor had changed, and that's why we couldn't recognize anything. All of a sudden it hit us that, wow, there had been an eruption. So it was very exciting."
In addition to producing hardened lakes of blobby lava, in places more than a mile across, the eruption changed the architecture of the region's seafloor hot springs.
"There are more vents, they're higher temperature, and there are microbes living in them that are usually deep in the crust that come up to the surface in these events," Chadwick told OurAmazingPlanet.
Eruption predicted
The Axial Volcano rises 3,000 feet above the seafloor, the most active of a string of volcanoes along the Juan de Fuca Ridge, a plate boundary where the seafloor is slowly pulling apart.
Chadwick and colleagues have been keeping tabs on the peak since it last erupted in 1998. Thanks to a monitoring system they developed to measure the mountain's minute movements, the team predicted the volcano was due for another eruption sometime between 2011 and 2014.
"So for me, it's a very exciting thing that this worked!" Chadwick said.
The instruments kept track of the movement of the seafloor, which very gradually inflates and deflates like a giant, magma-filled balloon, Chadwick said, collapsing suddenly after an eruption, and rising, in this case, by about 6 inches a year in the lead-up to an eruption.
First long-term picture
Scientists have long known about the existence of subsea volcanoes, but information on their behavior is relatively sparse. Eruptions were first observed in the 1990s, and, although technology has improved, getting to the underwater peaks to study them is difficult.
Data from the Axial Seamount's recent eruption will provide the first long-term picture of a subsea volcano from one eruption to the next.
Chadwick said scientists are still trying to figure out how seafloor volcanoes differ from their terrestrial counterparts.
It could be it's easier to predict ocean eruptions, Chadwick said. It's possible that because the crust is thinner there, and magma is in ready supply, the mountains' slow inflations provide a good analogue for knowing when eruptions will occur. However, he cautioned that a single successful prediction wasn’t enough to forecast what the future holds.
"At Axial, we've only seen this once, so we don't know for sure it's going to be reliable," Chadwick said. "So we'll certainly keep making these measurements, and hopefully be around to see what happens next."
An undersea volcano has erupted off the coast of Oregon, spewing forth a layer of lava more than 12 feet thick in some places, and opening up deep vents that belch forth a cloudy stew of hot water and microbes from deep inside the Earth.
Scientists uncovered evidence of the early April eruption on a routine expedition in late July to the Axial Seamount, an underwater volcano that stands 250 miles off the coast of Oregon.
The discovery came as a surprise, as researchers attempted to recover instruments they'd left behind to monitor the peak a year earlier. When the researchers hefted a seafaring robotic vehicle overboard to fetch the instruments, the feed from the onboard camera sent back images of an alien seafloor landscape.
"At first we were really confused, and thought we were in the wrong place," said Bill Chadwick, a geologist with Oregon State University. "Finally we figured out we were in the right place but the whole seafloor had changed, and that's why we couldn't recognize anything. All of a sudden it hit us that, wow, there had been an eruption. So it was very exciting."
In addition to producing hardened lakes of blobby lava, in places more than a mile across, the eruption changed the architecture of the region's seafloor hot springs.
"There are more vents, they're higher temperature, and there are microbes living in them that are usually deep in the crust that come up to the surface in these events," Chadwick told OurAmazingPlanet.
Eruption predicted
The Axial Volcano rises 3,000 feet above the seafloor, the most active of a string of volcanoes along the Juan de Fuca Ridge, a plate boundary where the seafloor is slowly pulling apart.
Chadwick and colleagues have been keeping tabs on the peak since it last erupted in 1998. Thanks to a monitoring system they developed to measure the mountain's minute movements, the team predicted the volcano was due for another eruption sometime between 2011 and 2014.
"So for me, it's a very exciting thing that this worked!" Chadwick said.
The instruments kept track of the movement of the seafloor, which very gradually inflates and deflates like a giant, magma-filled balloon, Chadwick said, collapsing suddenly after an eruption, and rising, in this case, by about 6 inches a year in the lead-up to an eruption.
First long-term picture
Scientists have long known about the existence of subsea volcanoes, but information on their behavior is relatively sparse. Eruptions were first observed in the 1990s, and, although technology has improved, getting to the underwater peaks to study them is difficult.
Data from the Axial Seamount's recent eruption will provide the first long-term picture of a subsea volcano from one eruption to the next.
Chadwick said scientists are still trying to figure out how seafloor volcanoes differ from their terrestrial counterparts.
It could be it's easier to predict ocean eruptions, Chadwick said. It's possible that because the crust is thinner there, and magma is in ready supply, the mountains' slow inflations provide a good analogue for knowing when eruptions will occur. However, he cautioned that a single successful prediction wasn’t enough to forecast what the future holds.
"At Axial, we've only seen this once, so we don't know for sure it's going to be reliable," Chadwick said. "So we'll certainly keep making these measurements, and hopefully be around to see what happens next."
Tuesday, August 16, 2011
Alaska Volcano May Disrupt U.S.-Asia Flights
International Business Times from 8/15/2011: Alaska Volcano May Disrupt U.S.-Asia Flights
Several thermal anomalies were observed in satellite views of Alaska's Cleveland volcano over the past 24 hours, but the Alaska Volcano Observatory said Sunday it had received no additional information or observations about activity.
Cleveland currently has an Orange Alert Status which means "explosive eruption is possible within a few days and may occur with little or no warning. Ash plume(s) are not expected to reach 25,000 feet above sea level." AVO predicts "increased numbers of local earthquakes" and "extrusion of a lava dome or lava flows (non-explosive eruption)."
Without a real-time seismic network on the volcano, AVO says it cannot track local volcano-related earthquake activity, provide forecasts of eruptive activity, or confirm explosive or ash-producing events. The observatory is monitoring the volcano using satellite data as it becomes available.
Scientists monitoring the volcano are expecting a more explosive event and have predicted a potential threat on the U.S. - Asia flight corridor used by major airlines, according to The Weather Space.
Mount Cleveland is a stratovolcano that comprises the entire western half of Chuginadak Island, 40 km west of Umnak. Although it is the tallest member of the Four Mountains group, Cleveland is reported to lose snow more rapidly than its neighboring peaks presumably from anomalous heat generation. Hot springs were noted at the base of a volcano on Chuginadak in the 1800s.
Like many other Aleutian volcanoes, the lower flanks of Mount Cleveland, up to about 300 meters elevation, are more irregular and dissected than the upper flanks. The cones on the eastern half of Chuginadak Island are dissected by broad valleys presumably eroded in part by glaciers; in contrast, the upper cone of Mount Cleveland is virtually undissected.
Several thermal anomalies were observed in satellite views of Alaska's Cleveland volcano over the past 24 hours, but the Alaska Volcano Observatory said Sunday it had received no additional information or observations about activity.
Cleveland currently has an Orange Alert Status which means "explosive eruption is possible within a few days and may occur with little or no warning. Ash plume(s) are not expected to reach 25,000 feet above sea level." AVO predicts "increased numbers of local earthquakes" and "extrusion of a lava dome or lava flows (non-explosive eruption)."
Without a real-time seismic network on the volcano, AVO says it cannot track local volcano-related earthquake activity, provide forecasts of eruptive activity, or confirm explosive or ash-producing events. The observatory is monitoring the volcano using satellite data as it becomes available.
Scientists monitoring the volcano are expecting a more explosive event and have predicted a potential threat on the U.S. - Asia flight corridor used by major airlines, according to The Weather Space.
Mount Cleveland is a stratovolcano that comprises the entire western half of Chuginadak Island, 40 km west of Umnak. Although it is the tallest member of the Four Mountains group, Cleveland is reported to lose snow more rapidly than its neighboring peaks presumably from anomalous heat generation. Hot springs were noted at the base of a volcano on Chuginadak in the 1800s.
Like many other Aleutian volcanoes, the lower flanks of Mount Cleveland, up to about 300 meters elevation, are more irregular and dissected than the upper flanks. The cones on the eastern half of Chuginadak Island are dissected by broad valleys presumably eroded in part by glaciers; in contrast, the upper cone of Mount Cleveland is virtually undissected.
Satellite images show eruption on Alaska volcano
Google News from Auug 9: Satellite images show eruption on Alaska volcano
ANCHORAGE, Alaska (AP) — A volcano on a remote Alaska island has begun erupting, but poses little danger to people or aircraft, officials said Tuesday.
The eruption at Cleveland Volcano is a slow effusion of magma that is forming a lava dome, and not an explosive eruption that generates large ash plumes, said John Power, the scientist-in-charge at the Alaska Volcano Observatory.
"So far, it's just lava as far as we can tell from our satellite imagery and the people who have managed to see it from passing airplanes," he said.
The volcano is in a very remote area, on uninhabited Chuginadak Island, and that lowers the danger level.
"Certainly, if there were people who were going to be in the area, they would need to be concerned but there aren't many of those folks there right now," he said.
Currently the lava dome is confined within the summit crater. Power said the biggest danger would be if the lava dome began to grow large enough to spill out, then it could begin to generate ash-producing explosions.
"If it were to explode and push a bunch of ash up into the flight levels, then it would be a much more dangerous situation," he said.
Based upon past observations at several volcanoes, dome growth like this can go on for weeks to months.
"It's something we're going to be watching very closely, or as close as we can given our operational constraints there," he said.
There is no real-time seismic network at the volcano, located in the Aleutian Islands 939 miles southwest of Anchorage. Officials are not able to track local earthquake activity related to volcanic unrest. For pictures, they also have to rely on satellite imagery or what people in airplanes snap as they pass the volcano and send to the observatory.
Given the current level of activity and hazards, he said they don't plan to fly to the volcano, especially considering the expense.
But weather has cleared in the last few days to allow better satellite imagery.
"We've had a few good days where the top of the volcano has been sticking out of the clouds, so things are looking nice for us in terms of direct observations," Power said.
Short-lived explosions with ash clouds or plumes exceeding 20,000 feet above sea level are frequent on Cleveland. It last showed signs of unrest last summer, with a small ash emission and lava flows on its upper flanks.
The observatory says the last significant eruption of the 5,676-foot volcano began in February 2001 and eventually produced a lava flow that reached the ocean.
ANCHORAGE, Alaska (AP) — A volcano on a remote Alaska island has begun erupting, but poses little danger to people or aircraft, officials said Tuesday.
The eruption at Cleveland Volcano is a slow effusion of magma that is forming a lava dome, and not an explosive eruption that generates large ash plumes, said John Power, the scientist-in-charge at the Alaska Volcano Observatory.
"So far, it's just lava as far as we can tell from our satellite imagery and the people who have managed to see it from passing airplanes," he said.
The volcano is in a very remote area, on uninhabited Chuginadak Island, and that lowers the danger level.
"Certainly, if there were people who were going to be in the area, they would need to be concerned but there aren't many of those folks there right now," he said.
Currently the lava dome is confined within the summit crater. Power said the biggest danger would be if the lava dome began to grow large enough to spill out, then it could begin to generate ash-producing explosions.
"If it were to explode and push a bunch of ash up into the flight levels, then it would be a much more dangerous situation," he said.
Based upon past observations at several volcanoes, dome growth like this can go on for weeks to months.
"It's something we're going to be watching very closely, or as close as we can given our operational constraints there," he said.
There is no real-time seismic network at the volcano, located in the Aleutian Islands 939 miles southwest of Anchorage. Officials are not able to track local earthquake activity related to volcanic unrest. For pictures, they also have to rely on satellite imagery or what people in airplanes snap as they pass the volcano and send to the observatory.
Given the current level of activity and hazards, he said they don't plan to fly to the volcano, especially considering the expense.
But weather has cleared in the last few days to allow better satellite imagery.
"We've had a few good days where the top of the volcano has been sticking out of the clouds, so things are looking nice for us in terms of direct observations," Power said.
Short-lived explosions with ash clouds or plumes exceeding 20,000 feet above sea level are frequent on Cleveland. It last showed signs of unrest last summer, with a small ash emission and lava flows on its upper flanks.
The observatory says the last significant eruption of the 5,676-foot volcano began in February 2001 and eventually produced a lava flow that reached the ocean.
Friday, August 12, 2011
Submarine Axial volcano erupts near Oregon
From Tucson Citizen: Submarine Axial volcano erupts near Oregon
by Jonathan DuHamel
Researchers at the Oregon State University had a surprise when they went to the Axial seamount volcano located about 230 miles off the Oregon coast. Last year they had left instruments to record volcanic activity. When they returned, they found the instruments buried in lava.
The Axial volcano is located on the Juan de Fuca plate near Oregon’s coast. In a previous post I said this is the area Where the Next Big American Earthquake and Tsunami Might Occur.
According to the news release from Oregon State University:
What makes the event so intriguing is that the scientists had forecast the eruption starting five years ago – the first successful forecast of an undersea volcano.
When Axial erupted in 1998, the floor of the caldera suddenly subsided or deflated by 3.2 meters (10.5 feet) as magma was removed from underground to erupt at the surface. The scientists estimated that the volcano would be ready to erupt again when re-inflation pushed the caldera floor back up to its 1998 level.
The discovery of the new eruption came on July 28, when Chadwick, Nooner and University of Washington colleagues Dave Butterfield and Marvin Lilley led an expedition to Axial aboard the R/V Atlantis, operated by the Woods Hole Oceanographic Institution. Using Jason, a remotely operated robotic vehicle (ROV), they discovered a new lava flow on the seafloor that was not present a year ago.
This latest Axial eruption caused the caldera floor to subside by more than two meters (six feet). The scientists will be measuring the rate of magma inflation over the next few years to see if they can successfully forecast the next event.
According to NOAA:
Axial Volcano rises 700 meters above the mean level of the ridge crest and is the most magmatically robust and seismically active site on the Juan de Fuca Ridge between the Blanco Fracture Zone and the Cobb offset. It represents the product of intense volcanic activity from the Cobb-Eikelberg hotspot juxtaposed on the extensional field of the spreading center. Axial Volcano was first studied in the late 1970s and then mapped in greater detail by NOAA/VENTS with SeaBeam in the early 1980s. Following the initial discovery of venting in the northern portion of the caldera in 1983, a concentrated mapping and sampling effort was made in the mid-late 1980s.The summit of Axial Volcano is marked by an unusual rectangular shaped caldera (3 x 8 km) that lies between the two rift zones. The caldera is defined on three sides by a boundary fault of up to 150 m relief. Hydrothermal vents colonized with biological communities are located near the caldera fault or along the rift zones.
Monday, August 8, 2011
18 Indonesian volcanoes on alert status
The Jakarta Post: 18 Indonesian volcanoes on alert status
Eighteen Indonesian volcanoes are on “alert” status, two of which are at Alert Level 3, which is called “Siaga”, the Volcanology and Geology Disaster Mitigation Center says.
Center head Surono said Sunday in Jakarta the erupting Mount Lokon in North Sulawesi and Mount Ibu in North Maluku were the two volcanoes at Siaga status.
The center has adopted four levels of alert status: “Normal” (Level 1), “Waspada” (Level 2), “Siaga” (Level 3) and “Awas” (Level 4).
Surono said the conditions at Mt Lokon and Mt Ibu were currently considered most worrisome because they had been consistently erupting searing clouds affecting a radius of 2.5 kilometers.
He added, however, that the eruptions had not yet endangered people living around the volcanoes.
“The eruptions are heading west, while people are concentrated in east,” he said as quoted by tempointeraktif.com.
Surono added that 16 other volcanoes were at Level 2 alert status, “Waspada”, including Mt. Papandayan and Mt. Guntur in West Java.
“Locals have reported several quakes,” he said.
Surono said that President Susilo Bambang Yudhoyono had summoned him on Saturday to report the volcanoes’ status and the center’s preparations to anticipate possible disasters.
He said ideally there should be an expert monitoring the activities of each volcano in Indonesia, as is the case in Japan.
“Currently an expert handles five mountains.”
Eighteen Indonesian volcanoes are on “alert” status, two of which are at Alert Level 3, which is called “Siaga”, the Volcanology and Geology Disaster Mitigation Center says.
Center head Surono said Sunday in Jakarta the erupting Mount Lokon in North Sulawesi and Mount Ibu in North Maluku were the two volcanoes at Siaga status.
The center has adopted four levels of alert status: “Normal” (Level 1), “Waspada” (Level 2), “Siaga” (Level 3) and “Awas” (Level 4).
Surono said the conditions at Mt Lokon and Mt Ibu were currently considered most worrisome because they had been consistently erupting searing clouds affecting a radius of 2.5 kilometers.
He added, however, that the eruptions had not yet endangered people living around the volcanoes.
“The eruptions are heading west, while people are concentrated in east,” he said as quoted by tempointeraktif.com.
Surono added that 16 other volcanoes were at Level 2 alert status, “Waspada”, including Mt. Papandayan and Mt. Guntur in West Java.
“Locals have reported several quakes,” he said.
Surono said that President Susilo Bambang Yudhoyono had summoned him on Saturday to report the volcanoes’ status and the center’s preparations to anticipate possible disasters.
He said ideally there should be an expert monitoring the activities of each volcano in Indonesia, as is the case in Japan.
“Currently an expert handles five mountains.”
Saturday, August 6, 2011
Eruptive Activity Eases At Kilauea Volcano In Hawaii
Irish Weather Online: Eruptive Activity Eases At Kilauea Volcano In Hawaii
Eruptive activity at Hawaii’s Kīlauea volcano has slowed during the last 24 hours, according to the United States Geological Survey (USGS) Hawaiian Volcano Observatory.
The crater floor and lava lake within Pu‘u ‘Ō‘ō collapsed and lava flowed out of its west flank on Wednesday, leading to the closure of some local roads in Hawai‘i Volcanoes National Park.
The USGS stated on Saturday: “In the east rift zone: short lava flows continued to issue from west flank vents; lava continued to trickle onto the collapsed floor of Pu`u `O`o Crater. At the summit, the lava lake surface continued to recede. Seismicity was generally low. Gas emissions decreased but remained elevated from summit and rift zone vents.”
Tourists have since flocked to the site to view dramatic glows from the new Pu‘u ‘Ō‘ō eruption from several vantage points. In addition, Kīlauea’s summit eruption at Halema‘uma‘u crater continues, and visitors can often hear the roar from rocks exploding off crater walls, and can observe a beautiful red glow after nightfall.
Viewing Details: East rift vents and flow field – The only lava erupting from Kilauea volcano’s east rift zone is within Pu`u `O`o Crater within Hawai`i Volcanoes National Park. Access and viewing information can be found here. Access via Kahauale`a Natural Area Reserve is closed by the state of Hawai`i Department of Land and Natural Resources. Kilauea Crater – Hawai`i Volcanoes National Park access and viewing information can be found here.
Wednesday’s activity was preceded on Tuesday by a 3.5 magnitude earthquake, 18 kilometres (11 miles) from the Kilauea volcano. The shallow tremor was recorded at 1:54 AM local time at a depth of 8.5 km (5.3 miles).
According to the United States Geological Survey (USGS) the tremor’s epicentre was located 16 km (10 miles) S (176°) from Fern Forest, 18 km (11 miles) S (185°) from Eden Roc, 42 km (26 miles) S (185°) from Hilo, and 358 km (222 miles) SE (127°) from Honolulu.
Kilauea presently is the world’s longest-lived volcanic eruption. Cycles of activity at the volcano’s summit have been stable for months, however, ever since lava flows at the Kamoamoa Fissure subsided in March 2011.
Deep within Halema’uma’u Crater (which is itself in the Kilauea Caldera) a small lava lake rises and falls as magma ebbs and flows within the volcano. Sensitive instruments monitor these movements by recording the tilt of the summit: decreasing tilt reflects deflation of the magma chamber, increasing tilt inflation. Each cycle of deflation and inflation usually lasts several days.
The above natural-color satellite image from earlier this week shows the summit of Kilauea Volcano, near the southern coast of the Big Island of Hawaii. Kilauea Caldera and Halema’uma’u Crater are both visible, as well as the Hawaii Volcano Observatory and the village of Volcano. The northeast, windward side of Kilauea is covered in dark green Ohia forest. The dry, leeward side is a nearly barren brown. Fresh lava flows are dark gray. A blue-tinted volcanic plume rises from within a pit near the southeastern edge of Halema’uma’u.
The volcanic plume, rich in sulfur dioxide gas, is emitted from the surface of a lava lake. In addition to falling and rising synchronously with the deflation-inflation events of the Kilauea Summit, the elevation of the lava lake varies in a series of fill-and-drain cycles that last minutes to hours. Sulfur dioxide emissions increase when the lake falls, and decrease when the lake rises. This suggests that gas within the lava lake is trapped when the surface of the lava hardens, and pushes the lake up like a piston. When gas is released, the lake level falls.
The bottom image was acquired by the Advanced Land Imager (ALI) aboard the Earth Observing-1 (EO-1) satellite. Caption by Robert Simmon, with thanks to Matthew Patrick, USGS Hawaii Volcano Observatory. Instrument: EO-1 – ALI
Wednesday, August 3, 2011
Volcano watchers raise alert status for Mount Cleveland
From Anchorage Daily News: Volcano watchers raise alert status for Mount Cleveland
Signs of lava at Mount Cleveland prompted volcanologists to raise their alert level Tuesday afternoon for the Aleutian Islands volcano.
The Alaska Volcano Observatory reports "heightened or escalated unrest" and the possibility of an eruption at the 5,676-foot volcano, according to the observatory's website.
Cleveland Volcano comprises the western half of Chuginidak Island, which sits about 115 miles west of Dutch Harbor and 950 miles southwest of Anchorage.
Satellite data and visual observations in late July revealed a lava dome about 140 feet in diameter growing in the volcano's crater, said volcanologist Chris Waythomas. The dome grew another 10 feet or so between Tuesday and Wednesday, according to the observatory.
"Sometimes lava domes like that can be explosive and lead to ash production," Waythomas said.
The volcano observatory raised the advisory status from "advisory" to "watch" and the aviation warning level from yellow to orange.
Cleveland is capable of blasting volcanic ash more than 20,000 feet into the sky -- a significant danger to air traffic in the vicinity -- so staff at the observatory decided to warn aviators of a possible explosive eruption, the researcher said.
Still, it's not certain that any ash-producing eruption will occur, Waythomas said.
"This could be the end of a little pulse of magma that's come into the volcano to form a little dome in there, and that'll be that, or it could lead to something more explosive," he said.
Because of a lack of seismographic equipment at the volcano, researchers must rely on pilot observations, satellite data and a webcam sometimes obscured by clouds, Waythomas said. An eruption could occur with little or no warning, he said.
Planes flying across the North Pacific Ocean or locally between islands would have to avoid the ash cloud, Waythomas said.
The most up-to-date information on Cleveland Volcano can be found at www.avo.alaska.edu.
Signs of lava at Mount Cleveland prompted volcanologists to raise their alert level Tuesday afternoon for the Aleutian Islands volcano.
The Alaska Volcano Observatory reports "heightened or escalated unrest" and the possibility of an eruption at the 5,676-foot volcano, according to the observatory's website.
Cleveland Volcano comprises the western half of Chuginidak Island, which sits about 115 miles west of Dutch Harbor and 950 miles southwest of Anchorage.
Satellite data and visual observations in late July revealed a lava dome about 140 feet in diameter growing in the volcano's crater, said volcanologist Chris Waythomas. The dome grew another 10 feet or so between Tuesday and Wednesday, according to the observatory.
"Sometimes lava domes like that can be explosive and lead to ash production," Waythomas said.
The volcano observatory raised the advisory status from "advisory" to "watch" and the aviation warning level from yellow to orange.
Cleveland is capable of blasting volcanic ash more than 20,000 feet into the sky -- a significant danger to air traffic in the vicinity -- so staff at the observatory decided to warn aviators of a possible explosive eruption, the researcher said.
Still, it's not certain that any ash-producing eruption will occur, Waythomas said.
"This could be the end of a little pulse of magma that's come into the volcano to form a little dome in there, and that'll be that, or it could lead to something more explosive," he said.
Because of a lack of seismographic equipment at the volcano, researchers must rely on pilot observations, satellite data and a webcam sometimes obscured by clouds, Waythomas said. An eruption could occur with little or no warning, he said.
Planes flying across the North Pacific Ocean or locally between islands would have to avoid the ash cloud, Waythomas said.
The most up-to-date information on Cleveland Volcano can be found at www.avo.alaska.edu.
Monday, August 1, 2011
Earthquakes under El Hierro in the Canary Islands: What can we expect?
Young-looking pahoehoe lava from El Hierro in the Canary Islands
From Big Think: Earthquakes under El Hierro in the Canary Islands: What can we expect?
Over the last few weeks, there has been a lot of buzz in the volcano world (at least in the internet) after some seismicity under El Hierro, one of the many volcanoes that make up the Canary Islands off the coast of Africa. The seismicity, although mostly of low magnitude (< M2), has been of high volume, with over 1,000 of this microquakes occurring since the swarm started in early July. Almost all the seismicity has been confined to depths of 9-16 km below the surface, which in a place like the Canary Islands, is close to/across the boundary of the lower crust and the upper mantle in an oceanic setting such as this. The question on everyone's mind is this: is El Hierro preparing for an eruption and, if not, what is going on underneath the volcano?
Before we can tackle those questions, we need a little context for the magmatism on the Canary Islands. The archipelago (one of my favorite words) is a Spanish territory that is as close as 115 km from the African coast. There are 7 islands that make up the Canaries, with El Hierro being the smallest. However, the volcanoes in the chain are large, towering from ~1051 meters above sea level to over 3700-meter tall Tenerife. A wide variety of lavas have erupted from Canary Island volcanoes, from your typical basalt like you find in Hawai`i to much stranger compositions like mugearites and phonolites. Most of the young volcanism (less than a few million years old) owes itself to a hotspot that rises underneath the archipelago, much as we find in Hawai`i, Iceland, Reunion Island and other oceanic islands. However, volcanism reaches back as far as 20 million years in the Canary Islands and may partially be the product of a propagation of the South Atlas fault zone (SAF) - but the true origin of the Canary Islands is hotly debated.
The volcanoes of the Canary Islands share many similarities with the volcanoes of Hawai`i. Many have the three-armed rift system layout like Kilauea, producing broad shield volcanoes that can grow very large. The eruption style (at least in historical times) tends to be fissure eruptions of lava flows with rare explosive eruptions when much silicic lavas, like phonolites, erupt.
El Hierro itself is one of the smaller volcanoes in the Canary Islands. There are a number of unconfirmed reports of eruptions over the past few hundred years (including the ambiguous reports of an eruption in 1793), but the last documented eruption of El Hierro occurred ~550 B.C., with another eruption approximately 400 years prior. The island itself is multiple volcanic centers, including the older El Tinor (~1.12 million years old) and El Golfo, which was active from ~545,000 to 176,000 years ago. New basaltic eruptions began around the same time the trachyte-dominated (alkaline) volcanism ended at El Golfo. It is though that the most active part of the Canary hotspot lies under El Hierro (see below), which explains the basaltic magmatism and appears that the highest concentration of young vents and lava flows lie on El Hierro. The island also has three large embayments on its coast, suggesting that large landslides may have come from the collapse of volcanoes on the island.
So, should we be surprised by this seismicity at El Hierro: No. Although not anywhere near as productive as Hawai'i or Iceland, the Canary hotspot is one of the more vigorous on the planet, as the 7 islands can attest. We see almost constant, low-level seismicity under parts of Iceland and Hawai'i due to magma rising underneath the islands from the mantle plume into the crust - and much of this intrusion is occurring in the 9-16 km zone that we see seismicity at El Hierro. Does this seismicity automatically lead to an eruption soon after the earthquakes when we observe them in Hawai'i or Iceland? Not necessarily. These intrusions can be bringing magma into the lower reaches of the magmatic system, but not producing eruptions in the days, weeks or even year timescales. Sometimes, this seismicity might not even lead to an eruption. However, now that we have many of these volcanic systems so closely monitored, we notice this subtle activity as it happens, rather than waiting until we can feel the seismicity at the surface - which usually means an eruption is definitely in the cards.
Does this mean that we should be concerned about an imminent eruption at El Hierro: probably not. This seismicity should remind us that El Hierro is an active volcano and these signals might be the vanguard to eruption in the future. However, without corroborating evidence like deformation of the volcano, increased carbon dioxide or sulfur dioxide emissions or changes in the seismicity (higher magnitude, shallower location), these earthquakes might just means that magma is recharging in the lower depths of El Hierro. As we've seen at Eyjafjallajökull in Iceland, it could be years between a seismic swarm that implies magma recharge and an eruption at the volcano.
However, even with this cautious take on what these earthquakes might mean, it is always a good idea to be prepared, especially when living on a volcanic island like El Hierro. Over 10,000 people live in the island and they should know what to do and where to go if El Hierro does decide to erupt - but remember, most eruptions produce lava flows and minor tephra/ash that are likely not a major threat to people unless you are caught completely unaware. People on Hawai`i have been living with an constantly-erupting volcano for over 30 years, so any activity at El Hierro should be impressive to watch, but not a catastrophe for the residents of the island.
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