Volcanos

Roundup of Global Volcanic Activity

Sakurajima (Kyushu, Japan): After a calm week during 12-20 April, the volcano is back with its typical average of 1-2 daily vulcanian explosions. Ash plumes have ranged from reaching 5-10,000 ft (1.5-3 km) altitude.

Batu Tara (Sunda Islands, Indonesia): The volcano seems to have entered a stronger phase of eruptions during the past days. A series of ash plumes from explosions were detected on satellite imagery since 26 April. The estimated altitude of the ash plumes is 8-10,000 ft (2.4-3 km) (VAAC Darwin).

Sinabung (Sumatra, Indonesia): The volcano continues to slowly aliment the large viscous lava lobe on the SE flank. Its growth is mainly manifested by numerous small to medium-sized rockfalls from its flanks and front, but also occasional pyroclastic flows that have reappeared since mid April. These new(, but much smaller than those earlier this year) pyroclastic flows have been triggered by comparably larger collapses that originated from the upper part of the lobe. The reason for the new pyroclastic flows might be that most arriving new lava, rather than contributing to the growth of the lobe as a whole, which is now a large and stiff mass difficult to move, now accumulates near the vent and starts to form a new lobe on top or at the side of the existing one. As the slope in the upper areas is steeper, it is easier for new lava masses to collapse into more energetic avalanches, i.e. pyroclastic flows.

Dukono (Halmahera): Ash plumes from (probably strong strombolian) explosions continue to be spotted on a more or less daily basis, suggesting that activity remains high.

Ahyi (United States, Mariana Islands): USGS raised the alert level for the submarine volcano due to abnormal seismicity detected in the area by hydroacoustic devices and land-based network devices on neighboring islands. However, the latter are relatively distant, such as Pagan located 270 km south. The source of the unusual signals that appreaed on 24 April can only be located approximately, and could originate from other seamounts near Ahyi volcano. For the time being, no other indications of possible volcanic submarine activity have been detected.

Popocatépetl (Central Mexico): Activity at the volcano remains low and essentially unchanged. The frequency of small steam-gas emissions was less than one per hour yesterday. Weak incandescence continues to be visible at the summit at night.

Santa María / Santiaguito (Guatemala): Activity remains relatively low and unchanged. Occasional explosions from the lava dome produce small ash plumes generally lower than 1 km. Only few avalanches were reported lately, suggesting that effusion rate has dropped.

Fuego (Guatemala): Activity has remained at normal, but relatively high levels, characterized by intermittent small to moderately strong strombolian explosions at intervals ranging from 10 minutes to more than 1 hour. The strongest explosions eject abundant glowing material to 150 m above the crater and ash plumes up to near 1 km, and are usually accompanied by shock waves felt in several km radius.

San Miguel (El Salvador): The Chaparrastique volcano remains restless. An increase in degassing and seismic activity on Sunday was reported. According to a local press article, MARN observed pulsating gas emissions that reached heights between 200 and 600 meters between 9-11 pm yesterday local time as well after midnight.

Reventador (Ecuador): The volcano’s activity remains moderate to high, with continuing sporadic explosions. Cloud cover has prevented direct observations most of the time.

Tungurahua (Ecuador): Activity of the volcano remains comparably low, with only few and weak emissions of low energy. A number of lahars, caused by heavy rains remobilizing loose deposits, occurred in the riverbeds of Ingapirca, La Rea, Achupashal and others streams on the S and SW sides.

Ubinas (Peru): Activity has decreased since 23 April: less and generally smaller explosions have occurred since, with a possible pause during 23-25 April when webcam images show no plume during daytime. However, during that time the volcano continued to produce an abundant degassing plume that sometimes contained some ash.

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