Volcano activity of July 12, 2012 - Papua New Guinea, Indonesia, Spain, California, Colombia, Ecuador, Nicaragua and Mexico

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 (main contributor) 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 12, 2012 volcano activity

A little more volcano news today than we've seen for awhile!

Seismicity remains elevated but, at relatively low levels at El Hierro (Spain) again today.  A M3.0 magnitude event punctuated the declining activity there.

Another short-lived swarm of approximately fourteen, low magnitude (all < M1.0) occurred along the same NNE trend south of Lassen Peak volcano (CA) on June 09-10.  That same feature (fault?) produced a slightly more vigorous episode of earthquakes last month.

Seismic activity near Long Valley caldera (CA) has migrated south into the Sierra Nevada mountains which rim the southern and western boundary of the volcanic system.

Volcano-tectonic seismicity has also ebbed at Popocatepetl volcano (Mexico) though pulses of spasmodic tremor continue in conjunction with exhalations of gas and some ash.

A local earthquake swarm is underway at Momotombo volcano (Nicaragua) (station (MOMN).  The volcano has experienced elevated seismic activity and emitted plumes of steam, possibly admixed with some old(?) ash during the past few years.

Erik Klemetti (Eruptions Blog) noted today that two more Colombian volcanoes are showing signs of unrest over the past few months to weeks.  Sotara volcano experienced a swarm of nearly 900 earthquakes between 25 June and 30 June and continues to exhibit numerous low magnitude low-frequency events (station  SOSO). Sotara has no historical record of eruption.
During the past few months, Cumbal volcano (Colombia) has experienced episodes of elevated earthquake activity (including locally felt events), noises and fumarole temperatures have risen to 210 degrees C.. The last notable seismicity at the volcano appears to have occurred on 08 June (station MEVN).  Because of the recent, sustained increase in activity, Cumbal volcano has been placed on "Yellow" alert.  A yellow alert level means that the volcano is showing (both internal and external) signs of unrest.  Eyewitness reports imply Cumbal experienced small explosions in 1926, though there is no geological evidence of such activity.

Due to timing of my issuance of this report, I missed some low-level eruptive activity at Tungurahua (Ecuador) yesterday (station RETU).

Volcano activity based on satellite imaging

Pago volcano, New Britain, Papua New Guinea : Based on analyses of satellite imagery, the Darwin VAAC reported that on 11 July an ash plume from Pago rose to an altitude of 4.3 km (14,000 ft) a.s.l. and drifted over 275 km SW.

Bagana volcano, Bougainville Island, Papua New Guinea : Based on analyses of satellite imagery, the Darwin VAAC reported that on 4 July ash plumes from Bagana rose to altitudes of 2.4-3 km (8,000-10,000 ft) a.s.l. and drifted 55 km W.

Bata Tara volcano, Indonesia : Based on analyses of satellite imagery, the Darwin Volcanic Ash Advisory Centre (VAAC) reported that on 8 July an ash plume from Batu Tara rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted almost 95 km SW.

Sangay volcano, Ecuador : According to the Washington VAAC, a thermal anomaly on Sangay was detected in satellite imagery during 4-6 July.