Volcano activity of November 18, 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. -

November 18, 2012 volcano activity

Little Sitkin volcano (Aleutians)appears to be preparing for another round of swarm activity.  Earthquake magnitudes and numbers are up again today. (station LSSA)
Seismicity continues to slowly dwindle beneath the South Moat of Long Valley Caldera (CA).  Only a few small quakes visible on the most recent seismograms. (station MMX1)
While surface activity is down, volcanic tremor and small earthquakes are visible on the seismic record from Popocatepetl volcano (Mexico) today.  Ignore the repeating pattern prior to 17z, it is due to a malfunction of the web software.
Tremor remains relatively continuous and at somewhat higher than normal levels at Pacaya (station PCG) and Fuego (station FG3) volcanoes (Guatemala).
Tremor has run a little higher than normal during the past week at Masaya volcano (station MASN) (Nicaragua) as well.  Infrequent small local earthquakes are also visible embedded in the activity.  At nearby Concepcion volcano (station CONN) pulses of volcanic tremor have become slightly stronger, but less frequent.
Low level tremor (and what appear to be small earthquakes) remains on seismograms recorded at Ruapehu volcano (New Zealand) this morning.  Small local earthquakes still dot the Tongariro seismogram and continuous tremor hums beneath White Island volcano again today.  I have included spectrograms recorded at each of the volcanoes which shows a recent, slight increase in tremor at Ruapehu (also recorded at Tongariro? Or is it weather noise?) in contrast with a strong low-frequency tremor signal at White Island.
Recent satellite imagery shows a relatively weak SO2-rich plume drifting from Popocatepetl (in-step with reduced surface activity at the volcano), and a much more prominent gas plume hovering over, as usual, Nyiragongo volcano (DRC).