This (almost) daily post intends to follow up the activity changes of volcanoes all over the world.
This post is written by geologist Rodger 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. -
March 25, 2013 volcano activity
The level of seismicity and ground deformation continues to climb today at El Hierro (Canary Islands). A magnitude M4.0 event was felt across the island late yesterday and a magnitude M3.4 event struck the island just minutes ago. Earthquake foci continue to hover around 15 km depth. Recent event epicenters have occurred closer to the northwestern shoreline than previously.
San Cristobal volcano (Nicaragua) (station CRIN) apparently wants to get involved in the action occurring around nearby Telica volcano. Several felt earthquakes, including a magnitude M4.3 event struck near that volcano this morning. The events appear to be tectonic in nature as the rate of volcanic earthquakes at San Cristobal have not changed. Meanwhile, at Telica (station TELN), volcanic seismicity remains high and occasionally grades into sub-continuous volcanic tremor. Still no reporting from INETER about the elevated seismicity at Telica. I'm not sure if event magnitudes have truly diminished at the volcano, or observatory personnel might have reduced the signal amplification on monitoring equipment in recent days. Compare the Telica spectrogram from 18 March (when unrest began in earnest) to the current one.
KVERT reports no significant changes in eruptive/seismic behavior at the five active Kamchatkan volcanoes: Tolbachik, Sheveluch, Bezymianny, Kizimen, and Karymsky. Moderate seismicity continues at hydrothermally active Gorely volcano.
Small local earthquakes are apparent on seismograms recorded at Makushin volcano (Aleutian arc) (station MSW) today. Seismicity has been elevated at times at Makushin for the past year. Numerous local, or at least nearby earthquakes, dot seismograms at Tanaga (Aleutian arc) (station TASE) and Mount Spurr (Alaska Range) (station CKT) volcanoes as well.
Small earthquakes also continue at Mount Hood volcano (OR) (station TDH). The two most recent locateable events have occurred beneath or in the vicinity of Crater Rock, a geothermally active feature near the volcano's summit.
Earthquakes continue beneath the "South Moat" of Long Valley Caldera (CA) (station MCS). Recent events cluster at the top of the primary magma "chamber" (at 8 km depth) believed to exist beneath the caldera. Dilatometers in the area show modest inflections in trend associated with the swarm activity.
Earthquake activity at Coso Volcanic Field (CA) continues to diminish but has included some of the shallowest (depth < 1 km) and strongest events (magnitude M2.0+) comprising recent swarm there.
Explosions, volcanic earthquakes, and rockfalls continue at a high rate at Colima volcano (Mexico). Exhalations of gas continue to occur at an average rate of nearly twice an hour at Popocatepetl volcano. The Popo seismogram continues to show low-level volcanic tremor and a few volcano-tectonic earthquakes occurring at the volcano.
Episodes of volcanic (eruptive) tremor have continued overnight at Pacaya volcano (Guatemala) (station PCG). Occasional low-level tremor, volcanic earthquakes and small strombolian explosions continue at Fuego volcano. Explosive activity appears to have increased at Fuego during the past few hours. Frequent hybrid earthquakes, rockfalls and short pulses of emission tremor affect Santiaguito Dome Complex (Santa Maria volcano) (station STG3) again today.
Volcanic earthquakes and occasional low-level pulses of volcanic tremor continue at Concepcion volcano (Nicaragua) (station CONN).
Volcanic tremor appears to be quieting at San Miguel volcano (El Salvador) (station VSM), but volcanic earthquakes still punctuate activity there. Obviously, telemetry interference continues to be a problem there as well.
A short pulse of volcanic earthquakes affected Rincon dela Vieja volcano (Costa Rica) (station RIN3) overnight.
A volcano-tectonic earthquake swarm appears to be ending at Nevado Del Ruiz volcano (Colombia) (station OLLZ).
Low-magnitude volcanic earthquakes continue to rattle Tungurahua volcano (Ecuador) (station OLLZ). Episodic bursts of (co-eruptive?) volcanic earthquakes and tremor continue at Reventador volcano (station CONE).
Strong, continuous volcanic/hydrothermal tremor rumbles within White Island volcano again today. Hybrid earthquakes have appeared in the mix during the past few hours at the volcano. GNS has reduced the aviation level of alert at Tongariro from "yellow" to "green" citing a lack of seismicity and little change in surface activity since the volcano's last eruption in November 2012. A few, small local earthquakes are visible on seismograms recorded at Ruapehu volcano today.
Recent OMI satellite imagery shows SO2-enriched plumes wafting from Popocatepetl, Turrialba (Costa Rica), Nyiragongo (DRC), Bagana (Bougainville Island), and Sakurajima (Japan) volcanoes. Current MODIS satellite data were not available at the time of this writing.