Budget cuts shrink AVO’s seismic network
Posted on February 11, 2014
Views of Fourpeaked volcano and area of volcanic activity on the north flank in 2006. (Photo by Christina Neal. Courtesy of Alaska Volcano Observatory / U.S. Geological Survey)
The ability to monitor several volcano’s in Alaska is being diminished due to funding constraints. The Alaska Volcano Observatory confirms that all of the monitoring instruments and stations at the Fourpeaked Volcano on the Alaska Peninsula have failed.
John Power is the Scientist in Charge for AVO.
“The cause is not completely known but the most likely thing is deferred maintenance. Maintenance that has not been performed. It’s beginning to catch up to us.”
Power confirms that AVO will continue to use satellite data, infrasound, and first hand reports from pilots to detect signs of eruptive activity. The Fourpeaked Volcano lies within the Katmai National Preserve and there have been no reported historical eruptions of the volcano. The announcement that the monitoring equipment on the Fourpeaked Volcano was not working comes on the heels of last month’s announcement that the same thing had occurred at the Aniakchak Volcano, also on the Alaska Peninsula. In total there are 5 volcano’s in Alaska that have monitoring equipment on them that are not currently working.
The Alaska Volcano Observatory is a joint program of the United States Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the State of Alaska’s Division of Geophysical Surveys. The Observatory was created in 1988.
Volcanic activity worldwide 11 Feb 2014: Kelud, Mammoth Mountain, Etna, Kilauea
Most likely, explosive lava-snow interaction and destabilization of this area where new magma was pushing its way outside caused a sector to collapse and descend the Valle del Bove flank as a hot turbulent avalanche (=pyroclastic flow). It reached the bottom of Valle del Bove in less than 3 minutes and traveled about 3 km length, which implies an average speed of 60 km/h, with maximum speed probably in excess of 100 km/h (approx. 65 mph).
... [read more]
...11 Feb:
The following is a comparison of some characteristic stages of the vents and lava flows on the eastern flank of the New SE cone:
Kelud (East Java): (11 Feb) VSI raised the alert status to the second highest level 3 (out of 4), "Siaga" (meaning eruption warning). In its latest report, VSI informs that an ongoing slight deformation, suggesting magma intrusion, has been detected since September and that a strong increase in seismic activity started on 7 February. A seismic swarm occurred with hypocenters between 1.5-3.5 km depth beneath the summit area.
The increased seismic activity triggered the decision to raise the status once more, after the volcano had put on alert level 2 already on 2 Feb.
Kilauea (Hawai'i): (10 Feb) 32 earthquakes were strong enough to be located beneath Kilauea Volcano in the past 24 hours, including 21 scattered broadly beneath the summit caldera.
Mammoth Mountain (California, USA): An small earthquake swarm at shallow depths (around 5 km) occurred east of Mammoth Mountain during the past week. The largest quake was a magnitude 3.0 event on 5 Feb.
This latest (of many in the past years) seismic swarm is weak in terms of number and energy of earthquakes compared to long-term averages of seismic activity at the Long Valley caldera, an active volcanic system that is capable to erupt (probably not in a near future, though) and is being closely monitored by very experienced staff from USGS.
It could be related to a small intrusion of magma, but is unlikely to be a precursor of a new eruption in any near future. USGS has not changed the status code of the volcanic system (at green=normal).
http://www.volcanodiscovery.com/volcano-activity/news/42538/Volcanic-activity-worldwide-11-Feb-2014-Kelud-Mammoth-Mountain-Etna-Kilauea.html
Rangitoto's buried past may reveal future eruption risk
Rangitoto’s buried past may reveal future eruption risk University of Auckland scientists are drilling deep into Rangitoto Island to investigate the volcano’s active past and provide a better understanding of the future risk to Auckland from eruptions.
Funded by EQC, the study is led by Associate Professor of Geology Phil Shane and researchers from the University’s School of Environment. The team are extracting continuous core samples up to 150m below the island’s surface.
"So far we have drilled to a depth of 40 m and found numerous thin lava flows. This shows how the volcano was built-up with time. It’s surprising the number of lava flows recorded. We think we've still got another 80-100 metres to go," Dr Shane says.
From samples taken, scientists will learn more about the duration and frequency of eruptions on Rangitoto over the past 1,000 years, information that will help hazard and risk planners such as Civil Defence significantly improve models of future volcanic activity.
"While we can’t predict the future, our research so far raises questions about if there was future activity in Auckland, how long would it last and could it be for longer periods rather than just months?"
Recent volcanic ash studies by the team resulted in the discovery that Rangitoto was more active for much longer than previously thought. As with other small basaltic volcanoes around the world, the island was thought to have erupted only once or twice about 500 years ago. However, studies of volcanic ash in sediments on the floor of Lake Pupuke show the island erupted intermittently or semi-continuously from about 1,500 years to 500 years ago.
This latest research will give a clearer idea not only of Rangitoto’s active past but in particular whether past eruptions were explosive or non-explosive.
"Rangitoto might have been erupting for nearly a thousand years and that’s a long time for this type of volcano. That radically changes the perception of potential future hazards in the region and the implications for Auckland as New Zealand’s largest city," Dr Shane says.
Rangitoto is the youngest and largest of the 50 volcanoes that make up Auckland’s volcanic field. It is 260m high and 5.5km wide.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Experts warn that as many as 750,000 would evacuate if Mount Fuji erupts
Julian Ryall in Tokyo
Volcano experts have warned that as many as 750,000 people may be forced to flee their homes if Japan's Mount Fuji erupts.
The 3,776-metre mountain - which was recently added to the Unesco World Heritage list - last erupted in 1707, but it is still classified as dormant rather than being labelled extinct.
A panel of experts was set up by three local authorities that share the peak, prompted in part by the upcoming third anniversary of the Great East Japan Earthquake of March 11.
A draft version of the panel's report, which is due to be completed in the early part of next year, says that 470,000 people will have to be evacuated if more than 30cm of volcanic ash settles on the ground. That figure climbs to 750,000 people leaving their homes if lava flows similar to the 1707 eruption occur.
Retired professor Shigeo Aramaki, who is on the expert panel, said there was a need for those living near Mount Fuji to be ready for a worst-case scenario, although he said it was notoriously tricky to predict significant seismic movements.
"A very large-scale disaster has a very low probability, although smaller-scale incidents will occur more frequently," he told the South China Morning Post.
"But this just goes to show that we cannot trust the science of seismology, especially after the events of March 2011."
That earthquake had an immediate impact on Japan's most famous mountain - a magnitude 6.2 earthquake was recorded on the southern flanks of the mountain just four days later, Aramaki said - although the longer-term impact is unclear.
What is evident is that any disaster similar to the 1707 eruption would potentially cause havoc. Rail and road connections to the south of the mountain that link Tokyo with Nagoya, Osaka and the west of Japan would almost certainly be severed by pyroclastic flow, the experts believe, while flights would be affected by all the ash emitted from the eruption.
Should a Volcanic Explosivity Index reading of level five occur, the experts predict, Tokyo would once again be smothered in ash, buildings would collapse under the weight and infrastructure would be severely damaged by lava flows.
It would take weeks for services to return to normal, they warn, and the cost would run into trillions of yen.
Aramaki said the magma chamber of the volcano was being closely watched as this could serve as an early indicator that an eruption is imminent.
Some researchers have suggested that there is cause for concern as the pressure in the chamber has risen to a level higher than it was in 1707.
"We are not able to accurately monitor the magma when it is deeper than 20km below the surface," he said.
"At the moment, it seems that there are no irregularities above that depth, but more than that we just do not know."
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NASA - Changed Landscape Around Sinabung
February 12, 2014
http://earthobservatory.nasa.gov/IOTD/view.php?id=83080&src=eoa-iotd
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NASA - Lava Dome Grows on Shiveluch
February 5, 2014
http://earthobservatory.nasa.gov/IOTD/view.php?id=83035&src=eoa-iotd
--
__._,_.___
No comments:
Post a Comment