Volcano activity of December 28, 2012

This (almost) daily post intends to follow up the activity changes of volcanoes all over the world.
This post is written by geologist Richard Wilson who specializes in Volcano seismicity and Armand Vervaeck. Please feel free to tell us about new or changed activity if we haven't written about it. -

December 28, 2012 volcano activity

Mostly reduced activity at the erupting volcanoes we watch today, while sequences of tiny earthquakes give promise for future activity at three other sites.

Little change in effusive activity at Plosky Tolbachik (Kamchatka Peninsula) the past day. KVERT reports that eruptive tremor amplitude is fluctuating and rises to only about one-quarter the level of two weeks ago.

Exhalations of gas and ash now occurr at Popocatepetl volcano (Mexico) an average of once per hour, down from the nearly five event per hour average of a week ago! The Popo seismogram also indicates a relatively tranquil volcano.

Seismic data from both Guatemalan and Nicaraguan were unavailable today, but judging by declining eruptive tremor at San Cristobal (Nicaragua) yesterday, the volcano's past behavior, and a lack of significant plumes in recent satellite imagery, thing's are likely returning to "normal" there. The same can be said of activity at the Guatemalan volcanoes where today's volcanocam photo of Fuego volcano depicts a generally peaceful scene with some minor incandescence from the active lava flow descending the volcano's flank.

Moderate co-eruptive seismicity continues at Tungurahua volcano (Ecuador) (station RETU) today. The volcano remains cloaked in clouds, so exactly what is transpiring at the vent remains a mystery for another day. EPN reports that the volcano remains inflated (especially beneath the upper north flank) which signifies that eruptive activity will likely continue for some time (probably weeks).

Today's volcanocam view of Copahue volcano (Chile) shows a relatively minor plume hovering over the volcano, while recent satellite imagery a new surge of SO2 eminating from the volcano in the past 24 hours. SERNAGEOMIN reports reduced seismicity from the volcano (13 located events) within continuous, low-level degassing/hydrothermal tremor. The extended eruptive plume from Sunday's outburst at Copahue continues to stretch over the southern Indian Ocean at this time.

Three USA volcanoes are showing some minor unrest. Makushin volcano (Aleutian arc) has shown elevated seismicity for much of this year. In the past few days, tiny (<M1.0) earthquakes have increased at the volcano (station MSW). Another (ongoing) surge of deep low-frequency earthquakes, indicative of fluid movement, beneath Mammoth Mountain volcano (CA) began early yesterday (station MRD). Event magnitudes comprising this swarm rarely exceed M1.0 unlike a much more energetic swarm that occurred at the volcano in late October. Tiny earthquakes also continue beneath the north shore of Lake Yellowstone (station ) where what is believed a magmatic dike injection occurred during the winter of 2008-2009.

Local earthquakes, both shallow and deep, continue to plague Machin volcano (Colombia) (station CIMA) again today. Small local earthquakes also continue at nearby Cumbal volcano (station MEVZ).

Across the pond in New Zealand, local earthquakes rattle Ruapehu volcano, and to a lesser extent Tongariro volcano. After holding at an elevated level for the past 10 days, volcanic tremor at White Island volcano has eased somewhat.

Recent satellite imagery shows SO2-enriched (indicative of "fresh" magma input) plumes eminating from Popocatepetl, Tungurahua, and Copahue volcanoes.

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