Volcano activity of December 27, 2012 - San Cristobal volcano, Nicaragua erupting (video)

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. -

December 27, 2012 volcano activity

Update : Just wanted to give you a head's-up about another deep low-frequency (magma movement) earthquake swarm that started beneath Mammoth Mountain volcano (CA) during the past day.  While not as energetic as the one at the end of October, the current swarm is comprised of numerous events at around 18-19 km depth (station MRD).

KVERT reports strong (but much reduced in amplitude) tremor accompanies the now largely effusive eruption at Plosky Tolbachik (Kamchatka Peninsula).

Inclement weather obscures eruptions in-progress at Tungurahua (Ecuador) and Copahue (Chile). Moderate to strong eruption tremor has re-appeared at Tungurahua in the past few hours (station RETU). SERNAGEOMIN reports that seismicity (33 volcano-tectonic and 2 volcanic earthquakes) increased at Copahue yesterday, but the eruption remains at a relatively low intensity.

In Nicaragua, volcanic tremor has eased but remains elevated at San Cristobal volcano (station CRIN). Over 15 explosions were recorded at the volcano yesterday. Notice the volcano "chugging" rhythmically on the picture below as pressure within the edifice drops.
Human impact of the eruption :
- 11 families living in Versalles Arriba and  Apastepe have been relocated to safer places.
- 217 families have auto-evacuated (mainly the slopes of the volcano) to families at safer places. They won't take a higher risk.
- Police is regulating traffic in the streets of Chinandega and El Viejo because of the poor visibility. Many locations around the volcano have layers of ash in the streets and people are wearing masks to be protected from gases and ash particles.

Exhalations of gas and some ash are reduced at Popocatepetl volcano (Mexico) today, averaging just over two per hour. The Popocatepetl seismogram shows a few small, local earthquakes.

Elsewhere, a swarm of tiny earthquakes began on Christmas eve beneath the north shore of Yellowstone Lake and now appears to be in decline. An intense swarm of earthquakes (with numerous M3-M4 events) struck this location on this date four years ago.

Occasional pulses of volcanic tremor, mixed with volcanic earthquakes continue to rattle Pacaya volcano (Guatemala) (station PCG) today. INSIVUMEH reports that several large explosions punctuated relatively quiet, slow dome growth at Santa Maria volcano yesterday. Ash clouds from the outbursts rose to over 10,000 feet asl. A few small explosions occurred at nearby Fuego volcano yesterday as well (station FG3). The Fuego volcanocam photo taken this morning shows the volcano in a peaceful state.

Episodes of weak volcanic tremor heralded the re-appearance of volcanic earthquakes at Concepcion volcano (Nicaragua) (station CONN).

Periodic trains of volcanic tremor have also affected Nevado Del Ruiz volcano (Colombia) (station OLLZ) during the past 24 hours. At nearby Machin volcano (station CIMA), earthquakes still eminate from the southeast "nest" of deep (12-15 km depth) seismicity beneath the edifice. A few small events also continue to be visible on recent seismograms recorded at Cumbal volcano (station MEVZ).

Seismic equipment at Reventador volcano (Ecuador) is still malfunctioning, but EPN reports low-level eruptive activity continues at the volcano.

In New Zealand, local earthquakes dot seismograms from Ruapehu volcano, records taken at Tongariro also show minor local activity, while volcanic tremor appears on the rise once again at White Island volcano.

Recent satellite imagery shows SO2-enriched plumes issuing from Popocatepetl, Tungurahua, San Cristobal, Turrialba (Costa Rica) and Nyiragongo (DRC)
volcanoes. The impressive SO2 plume from Sunday's outburst at Copahue volcano continues on its hemisphere-wide tour today over the southern Indian Ocean.