Friday, 29 March 2013

Volcanos

Roundup of Global Volcanic Activity:


El Hierro (Canary Islands, Spain): The latest CO2 measurements show a significantly higher than normal level of gas emission, consistent with fresh magma arriving from deeper sources. Another strong pulse of tremor and earthquakes (including a felt 3.8 magnitude event a short time ago) is in progress. The hypocenters of quakes have "dived" to 18-20 km depth, which could suggest a new batch of magma arriving from depth.


Tolbachik (Kamchatka): Volcanic tremor increased slightly and lava continues to effuse from the fissure vent and feed two main flow fields. No changes were reported recently for the other volcanoes in Kamchatka: seismicity remains at a moderate level at both Sheveluch and Kizimen volcanoes (lava dome building), while Tolbachik's tremor overrides the seismic signals from Bezymianny, which also has been effusing its lava dome for years.


Paluweh (off Flores Island, Indonesia): The lava dome on the island remains very active with now more or less daily ash plumes observed rising to 10,000 ft (3 km) elevation,- sign that active dome growth continues along with associated rockfalls / pyroclastic flows and explosions / ash venting.


White Island (New Zealand): Volcanic tremor is continuous and at high levels. Strong steaming can be seen on the webcam. GNS reported increased CO2 emission (1,950 tons/day on 03 March vs 2,400 tons/day on 26 March), which likely indicates influx of fresh magma at depth.


Colima (Western Mexico): Explosions and incandescent rockfalls sometimes forming small pyroclastic flows on the flanks of the volcano remain frequent. The rockfalls from the growing dome provide a spectacular show at night.


Popocatépetl (Central Mexico): the current phase of elevated activity continues. Emissions of steam and gas and small to moderate explosions have risen to an average of 3 per hour and sometimes merged into continuous activity yesterday and today. Some of the stronger explosions ejected lava bombs to distances of 1 km from the crater and produced plumes of steam and ash rising up to 1.5 km. CENAPRED also recorded spasmodic tremor segments of high frequency and low amplitude.


Fuego (Guatemala): An increase in explosive activity is apparent from the volcano observatory's daily reports. For the past 24 hours between yesterday and today, 13 explosions (7 weak and 6 moderate in size) were reported with ash plume heights up to 1200 m above the crater. The plumes drifted 8-12 km to the west and southwest and caused light ash falls in the areas Panimaché I and II, Morelia and Santa Sofía.


Telica (Nicaragua): The earthquake swarm continues with high amplitude but less frequent quakes.


San Cristobal (Nicaragua): A phase of stronger tremor has occurred today.


Masaya (Nicaragua): Volcanic tremor has been fluctuating between elevated levels (such as yesterday and this morning) and normal background levels to which is has decreased again now.


Machin (Colombia): Seismic activity remains elevated with frequent earthquake swarms. A probably shallow swarm occurred yesterday, but has now eased again. INGEOMINAS locates most volcanic-tectonic earthquakes in an area SE of the dome at depths between 3.5 - 8 km. No surface activity has been observed (yet).


Galeras (Colombia): During clear days, steaming and occasional weak ash venting (on 22 and 25 March) was observed. Seismic activity has shown a decreasing trend recently, INGEOMINAS reported. Most earthquakes detected at the volcano recently were related to internal fluid movements and of weak energy.


Nevado del Ruiz (Colombia): No significant changes in activity have been reported in recent days. Small bursts of small volcanic-tectonic earthquakes, indicators of frequent small magma intrusions, continue to show up almost daily, and are clustered mostly in an area northeast and northwest of the Arenas crater at shallow depths between 0.5-8 km. Strong degassing accompanies this process at the surface. A large SO2 plume was visible on yesterday's NOAA satellite data.


Reventador (Ecuador): A steam column was seen rising 1 km above the crater yesterday. Seismic activity remains alternating between periods of calm and bursts of tremor / explosion signals.

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