Volcano activity of October 13, 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. -

October 13, 2012 volcano activity

The Alaskan volcanoes have all slipped back into slumber, but small earthquakes rumble beneath Mount Hood (OR) (station TDH), Long Valley Caldera (CA) (station MCS) and the Coso Volcanic Field (CA) (no nearby seismograms available).
To the south, Popocatepetl volcano (Mexico) continues to perk at a low level with exhalations of gas and ash every few hours on average.
In Guatemala, volcanic tremor is on the increase (mixed with telemetry interference) at Fuego volcano (station FG3).
Telemetry interference also mars the seismic records from San Miguel volcano (El Salvador), giving the appearance of tremor there.  The numerous smaller magnitude events are real low-frequency (volcanic) earthquakes though (station VSM).
Tremor (again, mixed with telemetry spikes) is increasing at Concepcion volcano (Nicaragua) today (station CONN).
Two Colombian volcanoes were restive overnight.  Two swarms of what appear to be low-frequency earthquakes struck Machin volcano during the past 24 hours (station CIMA), and another swarm in as many days struck Nevado Del Ruiz volcano during the same period (station OLLZ).
Continuous harmonic tremor plagues White Island volcano (New Zealand).
Recent satellite imagery shows a strong SO2 plume issuing from Nyiragongo volcano (DRC), and lesser plumes detected at Popocatepetl (Mexico), Nevado Del Ruiz (Colombia), Ambrym (Vanuatu), and Fuego (Guatemala).  Concentrated SO2 is also apparent over northern Sumatra, in the vicinity of young volcanoes there, but smoke from forest fires and industrial emissions can also generate such anomalies.