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 29, 2012 volcano activity
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KVERT reports that the amplitude of volcanic tremor accompanying the effusion of basaltic andesite at Plosky Tolbachik (Kamchatka Peninsula) has risen slightly during the past 24 hours.
Eruptive activity at San Cristobal volcano (Nicaragua) (station CRIN) did ease (As I guessed yesterday without information from INETER) for a time yesterday, but activity has risen again at the volcano. INETER reports continuous ash emission from San Cristobal and lightning discharges from within the ash clouds and very high SO2 output from the volcano. A strong pulse of volcanic earthquakes in the past few hours resembles the premonitory signal on 22 December which preceded the current eruptive activity and may represent new slugs of gas and/or magma entering the shallow system of the volcano.
Richard Roscoe had the chance to witness a beautiful incandescent explosion on the slopes of Batu Tara volcano, Indonesia. Batu Tara volcano forms the Island of Komba which lies about 50km off the north coast of Lembata Island, one of the Lesser Sunda Islands belonging to Indonesia. The volcano is the most northeasterly volcano in the Flores-Pantar sector of the Sunda Arc which also includes the active Paluweh volcano. The associated Sunda Trench, where the Indian-Australian plate subducts under the southeastern extension of the Eurasian plate, lies south of the Arc.
EPN reports occasional loud explosions eminate from a once again cloud enshrouded Tungurahua volcano (Ecuador) (station RETU) today. I included a current photo of the volcano to show the typical Andean weather conditions that Ecuadoran volcanologists have to deal with. EPN did get the Reventador volcano seismometer (station CONE) back in service during the past day. That volcano has shown a marked decrease in activity the past few weeks.
SERNAGEOMIN reports only eight located earthquakes overnight at Copahue (Chile-Argentina border). This and today's volcanocam photo of the volcano all point to a general diminution of activity there.
CENAPRED reports exhalations (now mainly of gas) at Popocatepetl volcano (Mexico) occur an average of once per hour. The Popo seismogram shows some low-level volcanic tremor associated with the activity.
Activity is generally low at the three Guatemalan volcanoes we watch. Low level mostly internal activity is visible on seismograms recorded at Pacaya (station PCG) and Fuego (station FG3) volcanoes today. The Santa Maria seismogram (STG6) is illegible due to equipment malfunction. The morning shot from the Fuego volcanocam is quite spectacular, showing a small ash emission from the volcano's summit and bright incandescence from the lava flow descending the cone.
In the USA, the swarm of deep (~20 km depth) low-frequency (magma/gas movement) earthquakes beneath Mammoth Mountain volcano (CA) (station MRD) has ended as quickly as it began (on 27 December). Tiny events continue at the volcano. Tiny events also continue beneath the north shore of Yellowstone Lake (station LKWY).
Arenal volcano (Costa Rica) (station VACR) has also shown an increase in internal activity in the past day.
While San Cristobal volcano has been the focus of attention in Nicaragua, amplitudes and numbers of volcanic earthquakes have increased at nearby Concepcion volcano (station CONN) as well.
In Colombia, small earthquakes and occasional low-level volcanic tremor rattle Nevado Del Ruiz volcano (station OLLZ), Galeras volcano (station ANGV), and small, deep (12-15 km depth) earthquakes continue to affect Cerro Machin volcano (station CIMA).
Small "chugging" earthquakes (indicative of fluid/gas movement) have re-appeared on seismograms at Tongariro volcano (New Zealand) overnight. Seismometers at nearby Ruapehu show mostly wind noise today. After falling-off alittle yesterday, volcanic tremor has increased again at White Island volcano. A very unstable volcanic system indeed!
Recent satellite imagery shows SO2-enriched plumes drifting from Popocatepetl, Nevado Del Ruiz, Tungurahua, Krakatoa (Indonesia), and Langila (New Guinea) volcanoes.