Volcanos

Roundup of Global Volcanic Activity:

Stromboli (Eolian Islands, Italy): Activity continues at moderately elevated levels. Spectacular explosions especially from the NE crater can often be seen on the webcam as well.

Etna (Sicily, Italy): The earthquake swarm on the SE flank seems already to have come to an end. No eruptive activity is currently occurring at the summit craters. Strong wind and cloud cover prevented a field visit today. A swarm of shallow (3-6 km depth) earthquakes including several felt ones (magnitudes 2.9-3.5) occurred yesterday and today under the SE flank near Zafferana town. So far, no other unusual signs of activity have been reported, but the swarm could indicate something in the making, and the monitoring agency INGV is certainly following these events closely.

Bagana (Bougainville Island, Papua New Guinea): An explosion produced an ash plume rising to 7,000 ft (2.1 km) altitude and drifting 20 nautical miles to the NW earlier today. (VAAC Darwin)

Paluweh (off Flores Island, Indonesia): (24 May) Ash plumes rising to 10,000 ft (3 km) altitude have been observed yesterday and today. The lava dome obviously continues to be active and regularly produces explosions and/or rock avalanches that cause ash plumes.

Lassen (California): (24 May) A shallow magnitude 5.7 earthquake occurred Fri, 24 May at 04:58 UTC km WNW of Greenville, California, about 50 km SE of Lassen volcano. Hundreds of aftershocks, some of them felt, have occurred. It is unlikely that the earthquake has any relation with the volcano. The status of Lassen volcano remains therefore at green.

Popocatépetl (Central Mexico): Activity has not changed much, but perhaps decreased a bit today. During the last 24 h, CENAPRED recorded 3 explosions of moderate intensity, yesterday at 15:40 h, this early morning at 06:46 h and at 10:00 h (local time). All of them were accompanied by a column of gas and ash of 1.5, 1 and 2 km height, respectively. Several episodes of tremor were registered as well: 3 h of harmonic tremor of low amplitude, 5 h 40 min of spasmodic tremor of low amplitude and 2 h 30 min of spasmodic tremor or medium amplitude. This seismic signal was accompanied by a constant emission of steam, gas and small amounts of ash, that reached between 500 to 900 m and travelled to the southwest, and by moderate to strong incandescence over the crater rim. Some incandescent fragments could be sporadically be observed falling on the highest parts of the north and northeast flanks.

Santa María / Santiaguito (Guatemala): Activity remains low. A moderate explosion occurred last night at 17:55 h (local time) erupting an ash plume rising 600 m and drifting SW and causing light ash fall in Finca La Florida and Parcelamiento Monte Claro. Otherwise, the dome is degassing and a few weak avalanches occurred from the lava flow on the southern flank of the dome.

Pacaya (Guatemala): Strombolian activity from the Mackenney is gradually intensifying and continues to fill the crater. Explosions reach 75 m height above the vents and some of the ejecta fall outside the crater and produce audible booms. This activity and volcanic tremor is visible on the seismic recording as well.

Fuego (Guatemala): Explosive activity has picked up a bit. INSIVUMEH reported strong degassing noises and 5 weak and 4 moderate explosions since yesterday, some of which produce plumes of about 1 km height and drifting 10 km to the W and NW. Light ash fall occurred in the areas of Panimache 1 and 2, Morelia, Santa Sofía, El porvenir and Yucales.

Nevado del Ruiz (Colombia): The volcano remains restless and shows significant degassing activity. Elevated SO2 emission visible on the latest NOAA satellite data is probably the result of the recent magma intrusions. Seismic recordings show internal fluid movements, degassing tremor and occasional small quakes.

Sangay (Ecuador): (24 May) A possible ash emission occurred yesterday at 17:15 GMT, VAAC Washington reported. A pilot observed an ash plume at 25,000 ft (7.5 km) altitude drifting west from the volcano, but no ash could be detected on satellite data.

Reventador (Ecuador): No significant changes have occurred recently. The volcano remains active at moderate levels and produces a steam plume 800-1000 m high and occasional small explosions.

Tungurahua (Ecuador): Activity continues to be very low (steaming / degassing).

Copahue (Chile/Argentina): A steam and ash plume is rising about 1-1.5 km from the crater where it is emitted by 3 vents. Two of these emit only gas and steam. The third one erupts some ash as well, Chilean scientists found out during an helicopter overflight. It seems that (for now) this activity is phreatic, i.e. involves no fresh magma, only overheated water from the hydrothermal system, that can fragment rock into ash during explosive decompression. Temperature measurements gave a value of only 200°C at the vents.