Volcano activity of September 12, 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. -

September 12, 2012 volcano activity

Most volcanoes have returned to their "routine" patterns of activity, after a rather "busy" last few days.
After putting on a primer on andesitic volcano seismicity yesterday, Little Sitkin volcano (AK) has settled back into its steady, relatively low-level earthquake pattern (I still think it's pre-eruptive though!) (station LSSA).
Earthquakes are still occurring at or around Popocatepetl volcano (Mexico), but software problems make the pattern there hard to decipher.
Two Guatemalan volcanoes show increasing activity.  Volcanic tremor is on the rise at Fuego (station FG3) and Santa Maria (station STG6), while weak pulses of tremor continue at Pacaya (station PCG).
Numerous low-frequency (volcanic) earthquakes and tremor affect San MIguel volcano in El Salvador (station VSM).
Volcanic seismicity at San Cristobal (Nicaragua) (station CRIN) has returned to a low level. Earthquake occurrence at Telica (station TELN) and Apoyeque (station APYN) volcanoes, while relatively high, is considered to be at a normal background level.
A swarm of volcano-tectonic earthquakes at Nevado del Ruiz volcano (Colombia) (station OLLZ) has diminished over the past 24 hours, while small earthquakes and tremor have increased slightly at Galeras volcano (station ANGV).
Low-frequency earthquakes and tremor continue at Tungurahua volcano (Ecuador) (station RETU) today.
In New Zealand, small earthquakes remain apparent on seismograms at Ruapehu and Ngauruhoe (Tongariro?), while continuous volcanic tremor rattles White Island volcano.
Recent satellite imagery shows SO2-rich plumes at Popo, Nevado Del Ruiz, Ambrym (Vanuatu), and Sakurajima (Japan).


  1. Little Sitka very active last 45 minutes 10 am pdt