Wednesday 29 May 2013

Volcanos

Roundup of Global Volcanic Activity:

Tolbachik (Kamchatka): Eruptive activity continues, with fluid lava flows from the southern fissure being still emitted. However, also a very slow trend of decreasing tremor is visible. KVERT reports no significant changes in activity at any of the other volcanoes in Kamchatka: lava extrusion and dome building continue at Sheveluch and Kizimen. No seismic data are available at the moment from Karymski and Bezymianny, which also continues to slowly build a lava dome. Gorely produces medium levels of seismicity caused by fluid movements and strong degassing.

Yasur (Tanna Island, Vanuatu): Explosive (strombolian) activity level has been increasing recently, the latest bulletin of Geohazard today indicates. The alert level remains at 2, but an increase to 3 is possible in the near future. Elevated risk of impacts remains near the volcano's crater, as bombs have started to fall near and in the parking area. A thick steam and ash plume is being emitted from the active vents, and there is ash fall in communities downwind.

Pavlov (Alaska Peninsula, USA): The eruption might have ended already, or is at least pausing for the moment. Over the past few days, the eruptive and seismic activity have greatly declined, the Alaska Volcano Observatory reports. There are no longer volcanic tremor or small explosions detected and satellite observations show no evidence of elevated surface temperatures, volcanic gas or ash emissions. There have been no visual observations from pilots or web cameras of any eruptive activity. "Consequently, the Aviation Color Code is being reduced to Yellow and the Volcano Alert Level to Advisory.

Popocatépetl (Central Mexico): Since yesterday morning's explosion, the volcano has been relatively quiet and only produced about 1 weak emission of mostly steam per hour. No significant new earthquakes or tremor pulses have occurred.

Nevado del Ruiz (Colombia): Small earthquake swarms at shallow depth continue to plague the volcano. They suggest ongoing (small) magmatic intrusions. The other 5 volcanoes in Colombia currently on alert have not shown significant variations in activity (Galeras: degassing, occasional small ash venting, Cumbal, Machin, Sotará: seismic unrest but no surface activity, Nevado del Huila: degassing/steaming).

Copahue (Chile/Argentina): The earthquake swarm has increased and continues today, but the volcano has not yet erupted. The earthquakes are occurring at very high frequency (130 per hour) and are mostly "hybrid", i.e. related to both rock-fracturing and fluid-movements within the volcanic edifice. Evacuations in the area have progressed, but faced serious difficulties due to heavy snowfall and also because many residents in nearby villages are reluctant to leave their homes and live stock, especially in the municipalities of Butalelbùn (north side) and El Barco (south-west).

Nyiragongo (DRCongo): A significant SO2 plume is visible today on NOAA satellite data, suggesting continuing lava lake activity at the volcano. Unfortunately, security issues in the Goma-Virunga area continue to prevent us from organizing expeditions for the time being.

Two volcanos are erupting in Alaska: Pavlof and Cleveland.

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