Tuesday, 26 March 2013

Volcanos

Roundup of Global Volcanic Activity:


El Hierro (Canary Islands, Spain): The likelihood of a new submarine eruption in the near future is increasing. Earthquakes and pulsating strong tremor continued with little changes, indicators of magma intruding into new dikes in the western rift zone. There is also a trend towards stronger quakes (about 20 magnitude 3+ events including a M4 this morning) and shallower earthquakes (many at around 11-12 km depth today). This suggests that magma is slowly breaking pathways upwards, i.e. towards the seafloor. The area has remained about 5 km off shore NW from the western tip of the island, ie. under the submarine prolongation of the volcano's western rift zone. This is where now a new eruption should be expected, if the magma does not decide to migrate laterally once again.


Sakurajima (Kyushu, Japan): (25 Mar) Our friend Rainer Albiez just sent us the following report from Sakurajima, which is currently in a comparably lower phase of activity: "... just to give you short eruption update from Sakuajima volcano. Thursday it had 2 eruptions (according to visitor center info) in the period from Friday to Sunday 9 pm no eruption. Just mild strombolian activity in the crater, very few times 2-3 stones came over the rim. Very loud degassing and severe ash emissions. Weather conditions were not good (very misty, often cloudy partly raining) With high iso camera a a glow was visible within the crater (orange reflections in the clouds) but with eyes it was nearly not possible to see the glow (very light shine sometimes). Observation position was east of the crater."


Bagana (Bougainville Island, Papua New Guinea): An explosion produced an ash plume rising to 10,000 ft (3 km) altitude which drifted 25 nautical miles to the east. (VAAC Darwin)


Batu Tara (Sunda Islands, Indonesia): More explosions have been recorded by satellite data. This morning, an ash plume rose to 10,000 ft (3 km) altitude and drifted 25 nautical miles to the east. (VAAC Darwin)


Paluweh (off Flores Island, Indonesia): The lava dome remains active and regularly produces explosions and collapses with possible pyroclastic flows. VAAC Darwin reported an ash plume to 10,000 ft (3 km) altitude and extending 30 nautical miles to the west this morning.


Lokon-Empung (North Sulawesi, Indonesia): A series of 3 moderately large explosions occurred this morning between 05:12 and 07:30 local time, and was followed by small ash emissions during the whole morning. The largest eruption produced an ash column rising about 2 km above the crater.


Popocatépetl (Central Mexico): Activity has remained similar to previous weeks. The number of small explosions has risen a bit yesterday (1-2 per hour), and some of them were strong enough to eject glowing bombs to up to 500 m distance from the crater and creating ash plumes rising to about 23,000 ft (7 km) altitude or 1-1.5 km above the crater, drifting east. At night, glow continues to be visible, and a significant SO2 emission, both of which confirm that fresh magma is rising into the growing lava dome.


Telica (Nicaragua): Earthquake activity in the ongoing seismic swarm remains very high and there have been a few magnitude 2+ quakes at shallow depths today as well. There has not been any report from INETER yet.


Heard (Australia, Southern Indian Ocean): A significant heat source continues to show up on MODIS satellite data. A recent (9 March) EO1-Hyperion (NASA) satellite picture shows what could be a lava lake in the summit crater of Mawson Peak. This would be something in the line of the little what is known about the typical activity of Heard volcano, which has now been in eruption probably since end of September 2012.

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