VOLCANO MADNESS: [Geology2] Volcano News: April 8, 2013

Yasur volcano in Vanuatu upgraded to level 2

08 April, 2013

The Department of Meteorology and Geohazards in Vanuatu says it has upgraded the danger level of the volcano on Mr Yasur due to more explosions and ash eruptions.

The volcano on Tanna Island has been placed on alert level two, following an increase of activity recorded since last week.

A geophysical engineer at the Department, Sylvain Todman, says local communities are being warned to cover their water tanks and to be aware that ash could spoil gardens and fragile vegetables.

"It means more explosions, an increase of explosivity, more ash falling down to the close village and a lot of ash and some (volcanic) bombs falling down to the parking area and where the tourists used to witness the activity of the Yasur volcano."

Sylvain Todman says the Department of Meteorology and Geohazards is closely monitoring the activity and will prepare a response plan if the volcano increases to alert level three.

-- http://www.rnzi.com/pages/news.php?op=read&id=75135

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Volcanic activity worldwide 7 Apr 2013: Batu Tara, Galeras, Sabancaya, Bagana, Tjörnes Fracture Zone

Sunday Apr 07, 2013 |

Earthquakes in the TFZ during the past 48 hours (Icelandic Met Office)

Small ash emission from Galeras yesterday (INGEOMINAS)

Numbers of earthquakes at Sabancaya over the past weeks (IGP)

Tjörnes Fracture Zone (North of Iceland): The powerful earthquake swarm that started a week ago continues, but at reduced intensity compared to 2 April when the large magnitude 5.4 quake struck. Each day, hundreds of earthquakes have been occurring (more than 200 > magnitude 2 during the past 2 days).
The earthquake swarm is the result of release of tectonic stress that has accumulated in the crust and is being released at the moment. The area is one of the main so-called transform zones,- regions where the separating Eurasian and North-American tectonic plates move sideways along strike-slip faults rather than spreading apart directly as is the case in the main rift zones, where also the main volcanoes are located, because the opening movment here allows large batches of magma to rise easily.
... [read more]

Bagana (Bougainville Island, Papua New Guinea): A stronger eruptive phase has been occurring since last night. Several ash plumes reaching 10,000 ft (3 km) altitude have been observed drifting 45 nautical miles to the WSW (VAAC Darwin).

Batu Tara (Sunda Islands, Indonesia): Explosions continue with sometimes stronger ones that send ash to 7,000 ft (2.1 km) altitude on a daily basis now.

Galeras (Colombia): Ash emissions have become more frequent since 4 April - the Pasto observatory has reported daily small explosions since then. This marks a significant increase in activity. Before, the volcano had produced such emissions only a few times per month since September 2012.
No corresponding increase in seismic activity was reported and the (official) alert level remains at yellow (corresponding to "orange"="minor activity" on the scale we use).

Sabancaya (Peru): Seismic activity has decreased at the volcano, the latest press release of IGP shows. It seems less likely now that the volcano will produce an eruption soon,- as in many cases, an intrusion has happened at depth without (so far) breaching the surface (= erupting).

http://www.volcanodiscovery.com/volcano-activity/news/32165/Volcanic-activity-worldwide-7-Apr-2013-Batu-Tara-Galeras-Sabancaya-Bagana-Tjornes-Fracture-Zone.html

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Monitoring subsidence and vent wall collapse on Kilauea Volcano

Posted By News On April 7, 2013

Kilauea Volcano in Hawaii experienced its first summit eruption in 26 years when a new vent along the east wall of Halema`uma`u Crater opened in March 2008.

Since that time, the vent has become wider as parts of the wall around it became unstable and collapsed into the active lava lake within the vent, sometimes triggering small explosions. Richter et al. have monitored surface deformation in the area around the new vent since 2008 using interferometric synthetic aperture radar (InSAR) from the TerraSAR-X satellite along with a digital elevation model of the topography based on lidar data.

They were able to generate interferograms (a type of image) with a pixel resolution of about 3 meters (10 feet), which revealed centimeter-scale subsidence in the area within 100 meters (328 feet) of the vent rim. They note that this deformation cannot be detected by other techniques.

In general, the authors find that subsidence and increasing vent area track each other: the vent was more stable at times when subsidence rates were lower, while periods when the subsidence rate increased tended to be followed by collapse of
parts of the vent wall.

They suggest that it may be possible to identify areas where the vent rim is likely to fail soon on the basis of subsidence rate monitoring.

The study demonstrates the potential for using high-resolution satellite interferometry
for monitoring potential hazards.

TerraSAR-X interferometry reveals small-scale deformation associated with the summit eruption of Kilauea Volcano, Hawai'i

Nicole Richter: Department of Earth Observation, Friedrich-Schiller-University, Jena, Germany; Michael P Poland: Hawaiian Volcano Observatory, U.S. Geological Survey, Hawai'i National Park, Hawaii, USA; Paul R Lundgren: Jet Propulsion Laboratory, California Institute of Technology, Geophysical Research Letters, doi:10.1002/grl.50286, 2013

http://www.sciencecodex.com/monitoring_subsidence_and_vent_wall_collapse_on_kilauea_volcano-109883