Volcano activity of July 27, 2012 - Long Valley Caldera, Sheveluch, Sotara, Cumbal, Nevado del Ruiz, Sakurajima and Popocatepetl

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. -

July 27, 2012 volcano activity

I am glad to have "caught" the deep low-frequency earthquake activity beneath (actually a little west of) Mammoth Mountain volcano on the southwestern edge of the Long Valley Caldera (small purple dots). The activity started several days ago and was really active yesterday through today (small events on seismogram MRD). The earthquakes are of low magnitude (all less than M1.0), unusually deep (10-20 km) and have unusually low frequency content (1-3 Hz) when compared with "normal" tectonic earthquakes (6+ Hz). Such earthquakes are interpreted to result from fluid flow in the middle crust beneath volcanic areas. Shallow earthquake swarms sometimes follow deep low-frequency earthquake activity at Mammoth Mountain.

Elsewhere, seismicity has declined at both Nevado Del Ruiz and Galeras volcanoes (Colombia) the past several days, but amplitudes of shallow low frequency events at Sotara have increased during the same period (station SOSO) and a few very small events are apparent on seismograms at Cumbal (station MEVN), both volcanoes are also in Colombia.

Eruptive activity and seismicity has also declined the past few days at Popocatepetl (Mexico).

Sakurajima volcano (Japan) seems to be the volcano of the week this week!

Activity observed by satellites
VAAC Anchorage and VAAC Tokyo are reporting a rich volcanic ash cloud from Sheveluch volcano, Kamchatka, Russia early this morning. A new bulletin published around noon time UTC said that the ash was enough dispersed to become harmless for air traffic.  Sheveluch is at Orange alert for aviation .

Batu Tara volcano stills emits volcanic ash up to 7000 ft (2.1 km).

Interesting articles
Volcano Images
Thrill seeker Carsten Peter, 53 stood just inches away from the fiery mouths of the world’s most active volcanoes to take these sizzling shots showing fire work eruptions, flowing lava and life in the camps on the edge of the liquid rocks. This article has a lot of spectacular pictures (of course copyrighted). Click here to read this article and to watch the beauty of the photographed volcanoes.

Guatemala thermal power
Guatemala has been exploring geothermal power as a source of energy for some years now. The energy capacity for geothermal power generation is expected to increase exponentially by the year 2022 in Guatemala. The production capacity of energy with geothermal resources is expected to be around 1000 MW. Read more ...