Thursday, 28 March 2013

Volcanos

Roundup of Global Volcanic Activity:


Stromboli (Eolian Islands, Italy): It seems that activity has shifted a bit from effusive to explosive. The tremor signal has shown an increase today and includes very powerful explosion signals. On the other hand, lava overflows from the NE vent have decreased during the past days.


Etna (Sicily, Italy): 10 days since the last paroxysm, tremor is still low and doesn't suggest a new eruption is imminent. Bad weather mostly prevented observations during the past days. No glow could be seen last night from any of the summit craters.


Askja (Central Iceland): Small earthquakes have also been more frequent under and near the Askja caldera and Bardabunga volcano (to the SW of Askja) in the past few days.


Krafla (Northeastern Iceland): A weak swarm of earthquakes has occurred at Krafla over the past days.


El Hierro (Canary Islands, Spain): After a day of weakened activity, the seismic swarm has increased with higher energy tremor and stronger earthquakes than ever. Hundreds of earthquakes have occurred so far, including about 25 > magnitude 3 and no less than 4 above magnitude 4 (M4.1-4.6). It seems plausible that magma has once again built up pressure and has broken new fractures into the low crust beneath the NW part of the volcanic edifice. Many quakes are now at 11-15 km depth, i.e. the epicenters, or the likely present location of the intruding magma, has perhaps started to rise. The likelihood of a new eruption in a possible near future thus once again increased.


Manam (Papua New Guinea): A weak SO2 plume is visible today above Manam, indicating some ongoing activity. A hot spot at the summit is visible on MODIS data, likely indicating that a lava dome is growing there.


Paluweh (off Flores Island, Indonesia): Another ash plume was reported today rising to about 10,000 ft (3 km) altitude and drifting 20-30 nautical miles to the NE.


Colima (Western Mexico): Activity has continued to increase both internally and at the surface, with frequent explosions and glowing rockfalls and small pyroclastic flows traveling down the flank of the volcano.


Popocatépetl (Central Mexico): The rate of steam and sometimes ash emissions climbed to over 3 per hour yesterday. The larger emissions produced plumes with some ash content up to 1 km above the crater. SO2 emission remains elevated.


Santa María / Santiaguito (Guatemala): Activity remains more or less unchanged, but relatively weak. The volcano observatory reported to have heard 5 explosions during the past night, and notes ongoing weak to moderate avalanches from the active lava flows on the flanks of the Caliente lava dome.


Pacaya (Guatemala): Weak explosions producing small plumes of steam and some ash and degassing were reported this morning.


Fuego (Guatemala): Activity remains at weak levels, with 9 small to moderate explosions generating ash plumes rising up to 800 m above the crater and drifting W and SW where fine ash fall occurred.


Telica (Nicaragua): The earthquake swarm still continues and appears to show a slow trend towards increasing magnitude earthquakes including a magnitude 3 event two days ago.


San Cristobal (Nicaragua): A series of probably volcanic earthquakes of magnitudes between 2.8 and 4.9 shock the volcano during last Sunday evening (local time), and INETERS has increased monitoring of the volcano.

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