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. -
January 24, 2013 volcano activity
Hybrid earthquakes (red spikes in seismic record)(evidence for fluid movement) have continued to increase beneath White Island volcano (New Zealand) overnight, prompting GNS to upgrade the status of unrest at the volcano to "orange" level. I am hopeful that seismicity will slowly intensify right up to the initial explosion, affording everyone (scientists, airlines, tourists/sightseers) the maximum amount of time to prepare for an eruption, which is looking more probable now.
No significant changes at the Kamchatkan volcanoes today. Seismicity remains high at Plosky Tolbachik, and at moderate levels at Kizimen andSheveluch. Gorely volcano, which is only degassing at this time, also displays a moderate level of earthquake activity.
Local earthquakes continue at Tanaga volcano (Aleutian arc) (station TASE), though most of the seismicity visible on the Tanaga seismogram are aftershocks from a nearby tectonic earthquake which struck near the volcano on Monday.
Earthquake activity within Mount Rainier volcano (WA) (station RCS) has been slightly up the past few days. The apparent increase in activity is only partially real though, as the seismic monitoring network has recently been upgraded. The upgrade affords better event detection capability and thus allows events with magnitudes well below M1.0 to now be reliably located at the volcano. For example, of the eight earthquakes recorded at Mount Rainier during the past 3 days, only two had magnitudes larger than M0.5, and it is likely that only these two events could have been located without the recently improved monitoring system. I guess what I'm trying to say is, while this "increase" is scientifically interesting, the current small number of earthquakes shouldn't be a cause for worry about volcanic activity at the volcano. In September 2009, Mount Rainier experienced a swarm of over 1,000 small earthquakes (maximum magnitude M2.8), the largest swarm witnessed in over 40 years of seismic monitoring at the volcano,…and it STILL didn't erupt!
Earthquakes (only slightly larger than those at Mount Rainier) continue to occurr beneath Mammoth Mountain volcano (CA) (station MMS). Some shallower events ("yellow" dots depths < 3km) have occurred in the past day.
Volcanic earthquakes, small explosions, and rockfalls have increased atColima volcano (Mexico). Exhalations of gas and small amounts of ash now occur at Popocatepetl volcano an average of about once per hour. The Popo seismogram shows low-level volcanic tremor and small earthquakes occurring at the volcano.
Volcanic earthquakes and low-level volcanic tremor continue within San Cristobal volcano (Nicaragua) (station CRIN).
Volcanic tremor has intensified slightly and volcanic earthquakes have become more frequent at San Miguel volcano (El Salvador) (station VSM) overnight.
Numerous tiny earthquakes continue to affect Colombian volcanoesNevado Del Ruiz (station OLLZ), Machin (station CIMA), and Galeras(station ANGV).
Strong volcanic seismicity accompanies the apparent extrusion of a new lava flow at Reventador volcano (Ecuador) (station CONE). Small earthquakes are visible on seismograms at nearby Cotopaxi volcano (station CO1V).
Intense internal unrest continues at Copahue volcano (Chile-Argentina border) with 25 volcano-tectonic events, over 1000 volcanic earthquakes, and both harmonic and spasmodic tremor registered during the past 24 hours. Thus far, only a modest increase in eruptive plume height has occurred at the surface in conjunction with the internal activity.
Small local seismic events dot seismograms at Ruapehu volcano (New Zealand) today, while small "chugging" earthquakes and possible low-level volcanic tremor are visible on seismograms at nearby Tongariro volcano.
Recent satellite imagery shows SO2-enriched plumes drifting from Nevado Del Ruiz, Ubinas (?) (Peru), Ambrym (Vanuatu), Santa Maria (Guatemala), and Soputan(?), Una Una (?), Lokon(?), and/or Paluweh(?) (Sangihe arc) volcanoes.