Volcano activity of January 4, 2013 - another Mammoth Mountain deep earthquake swarm

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. -

January 4, 2013 volcano activity

Update : another Mammoth Mountain deep earthquake swarm
Another deep earthquake swarm at Mammoth Mountain volcano (CA).  I saw this one developing late last night actually, but larger magnitude (i.e. locatable) earthquakes began earlier today.  The intensity of the swarm again is not comparable to the late October 2012 sequence (thus far!), but what is interesting is that this one is focused at a significantly shallower level (~12 km vs.17-20 km for the previous swarms) and is centered directly beneath Mammoth Mountain rather than southwest of the edifice.  Dilatometers are also showing offsets in trend with the current swarm, whereas the last deep swarm (28-29 December) did not.  The December activity again was at around 20 km depth, was comprised of rather small magnitude earthquakes, and lasted only one day, which probably explains the lack of a clear response by dilatometers near the surface for that unrest. See LV and MRD graphs below

KVERT reports continued effusion of "very fluid" lava at Plosky Tolbachik (Kamchatka Peninsula) this morning. I speculate that the "very fluid" comment implies the eruption is now drawing upon a hotter magma which originated from greater (mantle?) depth. Upward movement of this "juvenile" magma was likely the culprit in initiating the eruption in the first place.

tolbachik_MODIS_20121222

Tolbachik_MODIS_Hotspot_20130104

Exhalations now occur at an average rate of once per three hour period at Popocatepetl volcano (Mexico). This is down from last week's nearly five event per hour average. The Popo seismogram reflects this low level activity.

imagenPopoTochimilco_20130104

Activity at the Guatemalan volcanoes, Pacaya (station PCG), Fuego (station FG3) and Santa Maria (station STG6) remains rather staid. We must keep our eyes on Pacaya though as seismicity at the volcano increased late in 2012 and has been accompanied by increased fuming and a small, mid-December 2012 ash eruption. The Pacaya seismogram shows the volcano is "perking" quite energetically today. The Santa Maria seismogram shows typical degassing tremor partially obscured by "noise" produced by malfunctioning seismic equipment. This morning's volcanocam photos depict incandescence in spots along the lava flow descending Fuego and a tall fume cloud rising above the Santiaguito Dome Complex (Santa Maria).

Fuego_20130104

Santiaguito_20130104

Elevated volcanic tremor at San Miguel volcano (El Salvador) (station VSM) fell-off abruptly overnight. The tremor-like signal between 2 and 3 UTC is due to equipment malfunction.

Internal activity, though gradually diminishing, remains elevated at San Cristobal volcano (Nicaragua) (station CRIN). Occasional trains of volcanic tremor punctuate otherwise quiet seismograms at nearby Concepcion volcano (station CONN).

Activity remains mainly internal at both Tungurahua (station RETU) and Reventador (station CONE) volcanoes (Ecuador) this morning.

A significant fume cloud (possibly mixed with some ash) continues to issue from Copahue volcano (Chile).

Copahue_20130104

Local seismicity remains relatively low at Ruapehu and Tongariro volcanoes (New Zealand), but there was another upward "spike" in continuous volcanic tremor affecting White Island volcano overnight.

Recent satellite imagery shows weak to moderate SO2-enriched plumes wafting from Bagana (Solomon Islands) and Krakatau (and perhaps Merapi) (Java) volcanoes.