Thursday, 11 April 2013

Volcanos

Roundup of Global Volcanic Activity:


Etna (Sicily, Italy): Strombolian explosions and relatively strong ash emissions from the New SE crater have continued throughout yesterday and the night, and seem to be gradually becoming more intense. However, this current behavior of Etna is a quite different from the usual more or less short build-up of activity the cone showed preceding the recent paroxysms. The tremor is slowly increasing.


El Hierro (Canary Islands, Spain): Earthquake activity has remained low, but there are still a few smaller quakes scattered under the island. This could be related to residual stress release caused by the relatively strong deformation the western part of the island experienced during the recent swarm.


Sakurajima (Kyushu, Japan): Since 4 April, no ash plumes / explosions have been reported from the volcano by Tokyo VAAC. This marks one of the longest intervals of relative quiet, i.e. absence of small to moderate volcanian explosions, in a long time. However, this does not exclude that minor explosive activity could be occurring.


Bagana (Bougainville Island, Papua New Guinea): More explosions have occurred. Ash emissions reached 7,000 ft (2.1 km) altitude, VAAC Darwin reported.


Manam (Papua New Guinea): An explosive eruption produced an ash plume rising to 7,000 ft (2.1 km) earlier today. The plume was observed on satellite data extending 40 nautical miles to the west (VAAC Darwin).


White Island (New Zealand): The strong volcanic tremor observed during the past days has dropped yesterday, but seems to be rising again today. GNS scientists reported that changes in water chemistry seen in recent samples from the White Island crater pool suggest that deep heat input into the volcano's plumbing system has diminished or ended. If this is right and the trend continues, White Island should return to a more stable state in the near future.


Douglas (United States, Alaska Peninsula): A series of earthquakes up to magnitude 2.6 has occurred in the past 24 hours beneath the eastern flank of the volcano at depths around 20 km.


Colima (Western Mexico): Eruptive activity continues with frequent small explosions, rockfalls, and sometimes larger pyroclastic flows.


Popocatépetl (Central Mexico): Activity has increased yesterday to about 3 emissions per hour and occasional small explosions creating plumes rising up to 500 m. Glow at the summit indicates continuing lava dome growth.


Pacaya (Guatemala): Strombolian activity continues gradually to increase, and tephra is being thrown to about 25 m above the crater rim. Inside the Mackenney crater, a small lava lake has formed at the vent at a depth of 40 m, INSIVUMEH reports.


Fuego (Guatemala): Activity has remained relatively low with only smaller strombolian explosions. At night, glowing bombs can be seen ejected to about 100 m above the crater.


Poas (Costa Rica): The seismic signal suggests increased tremor and signals of possible hydrothermal explosions. An elevated SO2 concentration above the area suggests a higher level of degassing activity.


Nevado del Ruiz (Colombia): The Manizales volcano observatory published a special bulletin because of increased activity from Ruiz. Starting at 02:18 (local time) this morning, continuous volcanic tremor has been recorded. This is similar to signals recorded between 8 and 21 March 2013, although this new episode of tremor is of lower energy level than in March. Very often, such seismicity is associated with emissions of gas and / or ash. Volcano webcams showed a steam/gas column rising 1600 m above the volcano and drifting NW, and possibly containing some ash in it.

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