This (almost) daily post intends to follow up the activity changes of volcanoes all over the world.
This post is written by geologist Rodger 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. -
January 31, 2013 volcano activity
KVERT reports volcanic tremor has diminished somewhat at Plosky Tolbachik (Kamchatka Peninsula) overnight, but remains strong. Seismicity has increased to moderate level at Karymsky volcano during the same period. Moderate seismicity also affects Sheveluch and Gorely volcanoes. Volcanic tremor produced by nearby Tolbachik masks seismicity that may be occurring at Bezymianny and Kliuchevskoi volcanoes.
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At the El Hierro volcano, Canary Islands, Spain a M2.9 earthquake occurred this afternoon. The location and the depth of the epicenter do remind on the Las Calmas undersea eruption episode in 2011/2012. Our in-depth reporting can be followed here.
Local (and some regional) earthquakes continue at/near Tanaga (station TASE) and Mount Spurr (CKT1) volcanoes today. Diagrams showing seismicity at the volcanoes contain all events for the past month.
A vigorous burst of seismicity occurred overnight beneath the Southern Moat of Long Valley Caldera (CA) (station MMS). An episode of inflation at the caldera ended late last fall. Earthquakes also cluster beneath Mammoth Mountain volcano, and along a NNE-trending structure within the Sierra Nevada Mountains south of the caldera.
Small explosions, rockfalls and occasional volcanic earthquakes have decreased during the past day at Colima volcano (Mexico). Exhalations of gas and some ash continue at an average rate of about once per hour at Popocatepetl volcano. Today's Popopocatepetl seismogram appears to show volcanic tremor.
Still no current seismic data available for the Guatemalan volcanoes. Today's Santiaguito (Santa Maria volcano) volcanocam photo shows mild degassing taking place at the lava dome complex.
Nearly all (save for Sotara) the Colombian volcanoes we watch show increased internal activity today. Small earthquakes have increased in number and magnitude at Nevado Del Ruiz (station OLLZ) and Machin (CIMA). Small earthquakes (and another pulse of tremor at Galeras) are also visible on seismograms recorded at Cumbal (station MEVZ) and Galeras (station ANGV) volcanoes.
Volcanic earthquakes (within a field of low-level volcanic tremor) continue to be frequent at Tungurahua volcano (Ecuador) (station RETU) today. Co-eruptive seismicity remains strong at Reventador volcano (station CONE).
SERNAGEOMIN reports decreased (but continuing) internal unrest at Copahue volcano (Chile-Argentina border), with 9 volcanic and 3 volcano-tectonic earthquakes, continuous low-magnitude volcanic tremor, in addition to 521 events believed related to the degassing process at the volcano. Today's Copahue volcanocam photo reveals a wind-swept plume of gas, possible mixed with ash.
GNS reported results of yesterday's gas flight on White Island volcano. SO2 levels have indeed increased, which can be ascribed to the volcanic system heating-up and "drying-out'. GNS interprets the relatively minor increase (366 tons/day to 600 tons/day) to re-mobilization of some "old" sulphur within the hydrothermal system (due to re-heating) beneath the volcano. CO2 levels have also increased (1900 tons/day to 2000 tons/day), as have levels of H2S (hydrogen sulphide) (15 tons/day to 19 tons/day. CO2 eminates from deeper in the volcanic system and its increase may reflect deeper input of magma beneath the volcano. Increased H2S together with increased SO2 results from shallow magma emplacement within the volcano. Seismicity at White Island continues to be high with continuous strong volcanic tremor and episodes of volcanic earthquakes. Seismograms from Tongariro volcano appear to show low-magnitude volcanic earthquakes today.
Recent satellite imagery shows SO2-enriched plumes drifting from Nevado Del Ruiz, Tungurahua, Reventador, and curiously, an SO2 anomaly directly over Cotopaxi volcano which may have experienced a swarm of volcanic earthquakes earlier this week! Another SO2 anomaly occurs over Soputan volcano (Sangihe arc).