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. -
April 30, 2013 volcano activity
KVERT reports no change in eruptive/seismic behavior of the five active Kamchatkan volcanoes: Tolbachik, Sheveluch, Kizimen, Bezymianny, and Karymsky today. Recent satellite data (from the MODIS and OMI platforms) show both SO2 and thermal anomalies associated with ongoing eruptive activity at Plosky Tolbachik. I have included recent MODIS real color images of Sheveluch and the Kamchatkan volcanoes we report on as a whole.
Also included in today's report are MODIS real color images of the effects of ongoing eruptive activity at Mount Etna (Italy) and Paluweh volcano (eastern Java). In the Mount Etna photo: Note the landslide scree forming along the eastern flank of the Southwest Crater vent. This feature indicates increasing instability of the eastern flank of the rapidly growing Southwest Cone. With time, the cone has grown toward the upper headwall of the Valle de Bove (an even larger active landslide which may influence the location of eruptive vents) and in recent eruptions, has produced relatively small collapses of incandescent material in to the upper reaches of the Valle. My concern is that, with more time and growth of the cone, the collapses may become large enough to threaten downslope communities. It is fairly simple to calculate the runout distance of cold avalanches, but as a result of their latent heat and continued degassing, hot avalanches can move much greater distances across much more subdued terrain. Fine material which rises above the hot avalanches as a surge can travel even further irrespective of the surrounding terrain. This bears watching during future paroxysms, which I'm sure Italian civil authorities and volcanologists are aware of. As for the photo of Paluweh volcano: Both airfall and pyroclastic flow deposits, produced by repeated dome growth (continuing) and collapse now blanket the entire island. Note also the abundant floating pumice and ash on the ocean surface surrounding the island.
Shallow earthquakes have continued overnight at Iliamna volcano (Alaska Range) (station INE).
Still no updated seismic data from Colima volcano (Mexico). Activity at Popocatepetl volcano has dropped-off again, Exhalations have been relatively small (incorporating only minor amounts of volcanic ash) and avergaed less than on event per hour during the past 24 hours. The Popo seismograms shows low-level harmonic tremor, a magnitude M2.0 earthquake which struck the volcano late yesterday, and a few small exhalation event signals.
Strombolian activity has diminished at both Pacaya (Guatemala) (station PCG) and Fuego (station FG3) volcanoes overnight. Fine ashfall, primarily raised by rockfalls from the snouts of two lava flows currently descending the flanks of Fuego volcano, has been reported from villages up to 10 km distant. Fuego also continues to produce frequent series of "locomotive-like" chugs heard at appreciable distances from the cone. Vulcanian explosions, while relatively small in volume/size, have increased in number during the past 24 hours at the Caliente Dome of the Santiaguito Dome Complex (Santa Maria volcano) (station STG3). Observers report loud degassing noises coming at 43 second intervals from Santiaguito today.
After several months of heightened seismicity, activity has returned to background level at Telica volcano (Nicaragua) (station TELN). Telica is one of those "noisy" volcanoes which always exhibits (relative to other volcanoes worldwide) a high level of internal unrest. The recent very high level of earthquake activity at the volcano illustrates why seismic data cannot be the sole criterion for judging whether a volcanic eruption is imminent (imagine forecasting weather based solely on barograph readings!). I won't report on Telica volcano on a daily basis (of course, unless something interesting is occurring!) following today's report.
Periods of elevated volcanic tremor have occurred at San Miguel volcano (El Salvador) (station VSM) overnight. The tremor pulses are kind of hard to discriminate from also periodic telemetry "noise".
A swarm of small seismic events is presently occurring at Poas volcano (Costa Rica) (station POA2). The tiny earthquake are likely associated with rapid introduction of heat beneath/into the Poas crater lake.
Short-lived swarms of volcano-tectonic earthquakes continue to punctuate a relatively quiet period at Nevado Del Ruiz volcano (Colombia) (station OLLZ). Tiny local earthquakes and small gas (and ash) emission events are apparent on seismograms from Galeras volcano (station CUVZ) today. The emissions have continued on nearly a daily basis at the volcano for over a month now.
Volcanic seismicity (in the form of elevated tremor and occasional explosion events) continues at Tungurahua volcano (Ecuador) (station RETU) today. The relatively steady and generally low-amplitude character of the seismicity indicates a somewhat "open" volcanic plumbing system and does not suggest (at this time anyway!) a major eruption in the offing. Amplitude of seismicity at Reventador volcano (station CONE) is quiet high today, but the Reventador volcanocam continues to show a largely white (SO2) plume emanating from the volcano.
Volcanic tremor has remained reduced overnight at White Island volcano (New Zealand).
Hurrah!! OMI satelite datya have been updated!!! Recent OMI images depict SO2-enriched plumes drifting from Tolbachik, Fuego, Nevado Del Ruiz, Mount Etna (Italy) and Nyiragongo (DRC) volcanoes. Plosky Tolbachik and Kilauea (Hawaii) continue to be the only volcanoes currently "hot enough" (or not covered in thick cloud) to be detected in recent MODIS satellite global transits.