Volcano
activity of February 21, 2013 – Iliamna + Etna now erupting during
KVERT reports no significant changes in eruptive behavior at the six erupting Kamchatkan volcanoes. Seismicity remains relatively high at Plosky Tolbachik (lava fissure eruption), moderate at Kizimen (lava flow/dome emplacement), and Karymsky (occasional strombolian/vulcanian explosions), and weak atKliuchevskoi (weak strombolian explosions), Sheveluch (lava flow/dome emplacement and occasional vulcanian/pelean explosions) and Bezymianny (lava flow/dome emplacement with occasional vulcanian/pelean explosions). Seismicity related to strong degassing continues at Gorely volcano. Recent MODIS satellite thermal imagery shows a multi-pixel anomaly corresponding to recently emplaced lava flows at Plosky Tolbachik.
Small earthquakes (and telemetry interference!) remain frequent at Alaska Range volcanoes Iliamna (station INE) and Mount Spurr (station CKT). Recent clear views of Iliamna (especially rare at this time of year!) have confirmed that a large avalanche/debris flow occurred recently at the volcano (likely on 02 February,…see our report for that date). The avalanche sourced in a “disturbed” area on the Red Glacier identified by AVO in March 2012 (all photos are by AVO except debris flow photos which were captured by local photographer Dennis Anderson). The glacier disturbance appears to have formed in-concert with the onset of unrest at Iliamna beginning in late 2011. The recent large avalanche occurred as another bout of strong earthquakes (maximum magnitude M3.1) struck the peak in early February. A smaller debris flow issued from the area in October 2012. It is likely that the initial glacier break-up was precipitated by increased thermal output (perhaps in pulses during enhanced seismicity) at the glacier sole. Increased thermal output, as well as increased magmatic gas output at Iliamna was verified early in the current period of unrest during overflights by AVO. I am speculating here but, the large debris flow could have been set into motion by small changes in slope on the volcano’s flanks that may have occurred (accelerated?) during this latest earthquake swarm. Located earthquakes that make-up the early February swarm suggest magmatic dike injection is focused south of the avalanche source, but interestingly, the strongest events locate directly beneath the Red Glacier disturbance. As I mentioned in the 02 February report, avalanches of this size are not unusual at Iliamna, but recent events beg at least some (increased) volcanic influence!
Small earthquakes (maximum magnitudes <M2.0) continue along the southern boundary of Long Valley Caldera (CA) (station MCM), especially in the Convict Canyon area (Sierra Nevada) south of the Mammoth Airport. A few of the events on today’s record are aftershocks from the M5.1 which struck western Nevada last week.
Pacaya volcano (station PCG) continues to have the most interesting seismograms of the three active Guatemalan volcanoes. The volcano continues to “perk” with numerous small volcanic earthquakes and occasional pulses of tremor.
daylight !
21
February, 2013
February 21, 2013 volcano activity
Etna had it’s 4th paroxysm earlier today, this time during daylight. The YouTube embedded video shows the volcano action of the 3th, yesterday, in a great way. Enjoy the Salvo Orlando video (www.sicilylandscape.com).
KVERT reports no significant changes in eruptive behavior at the six erupting Kamchatkan volcanoes. Seismicity remains relatively high at Plosky Tolbachik (lava fissure eruption), moderate at Kizimen (lava flow/dome emplacement), and Karymsky (occasional strombolian/vulcanian explosions), and weak atKliuchevskoi (weak strombolian explosions), Sheveluch (lava flow/dome emplacement and occasional vulcanian/pelean explosions) and Bezymianny (lava flow/dome emplacement with occasional vulcanian/pelean explosions). Seismicity related to strong degassing continues at Gorely volcano. Recent MODIS satellite thermal imagery shows a multi-pixel anomaly corresponding to recently emplaced lava flows at Plosky Tolbachik.
Small earthquakes (and telemetry interference!) remain frequent at Alaska Range volcanoes Iliamna (station INE) and Mount Spurr (station CKT). Recent clear views of Iliamna (especially rare at this time of year!) have confirmed that a large avalanche/debris flow occurred recently at the volcano (likely on 02 February,…see our report for that date). The avalanche sourced in a “disturbed” area on the Red Glacier identified by AVO in March 2012 (all photos are by AVO except debris flow photos which were captured by local photographer Dennis Anderson). The glacier disturbance appears to have formed in-concert with the onset of unrest at Iliamna beginning in late 2011. The recent large avalanche occurred as another bout of strong earthquakes (maximum magnitude M3.1) struck the peak in early February. A smaller debris flow issued from the area in October 2012. It is likely that the initial glacier break-up was precipitated by increased thermal output (perhaps in pulses during enhanced seismicity) at the glacier sole. Increased thermal output, as well as increased magmatic gas output at Iliamna was verified early in the current period of unrest during overflights by AVO. I am speculating here but, the large debris flow could have been set into motion by small changes in slope on the volcano’s flanks that may have occurred (accelerated?) during this latest earthquake swarm. Located earthquakes that make-up the early February swarm suggest magmatic dike injection is focused south of the avalanche source, but interestingly, the strongest events locate directly beneath the Red Glacier disturbance. As I mentioned in the 02 February report, avalanches of this size are not unusual at Iliamna, but recent events beg at least some (increased) volcanic influence!
Image
courtesy and copyright Dennis Anderson
Small earthquakes (maximum magnitudes <M2.0) continue along the southern boundary of Long Valley Caldera (CA) (station MCM), especially in the Convict Canyon area (Sierra Nevada) south of the Mammoth Airport. A few of the events on today’s record are aftershocks from the M5.1 which struck western Nevada last week.
Exhalations
of gas and some volcanic ash continue at a reduced rate
at Popocatepetl volcano
(Mexico), averaging less than once per hour. Today’s Popo
seismogram shows low-level volcanic tremor and small local events,
but most prominent is the M5.8 Coahuayana regional earthquake.
Pacaya volcano (station PCG) continues to have the most interesting seismograms of the three active Guatemalan volcanoes. The volcano continues to “perk” with numerous small volcanic earthquakes and occasional pulses of tremor.
San
Cristobal volcano
(Nicaragua) (station CRIN) experienced periods of banded tremor
overnight. NearbyMasaya voclano
(station MASN) also exhibits periods of elevated volcanic tremor.
Volcanic
tremor has also increased slightly at San
Miguel volcano
(El Salvador) (station VSM).
Small
earthquakes (and short pulses of tremor at Galeras) affect three
Colombian volcanoes: Ruiz (station
OLLZ), Machin (station
CIMA), Galeras (station
ANGV), and Cumbal (station
MEVZ) today.
Sustained
low-level volcanic tremor with occasional flurries of volcanic
earthquakes (as well as equipemnt malfunction!) continue
at Reventador volcano
(Ecuador) (station CONE). A flurry of volcanic earthquakes also
occurred at Cotopaxi volcano
(station CO1V) overnight.
Volcanic
tremor has risen to its highest level since unrest began at White
Island (New
Zealand) last year. Volcanic earthquakes also remain frequent
at the volcano. What appears to be a pulse of volcanic tremor
occurred overnight at Tongariro volcano.
Tiny local earthquakes are apparent on seismograms recorded at
nearby Ruapehu volcano.
Recent OMI
satellite imagery shows
SO2-enriched plumes wafting from Popocatepetl, Turrialba (Costa
Rica), Bagana (Solomon Islands), and Sakurajima (Japan) volcanoes.
MODIS satellite thermal imagery reveals multi-pixel “hotspots” at
Tolbachik and Etna (Italy) volcanoes.
No comments:
Post a Comment
Note: only a member of this blog may post a comment.