2009-02-06 13:05:32 - Weekly Update
Unrest at Redoubt Volcano continues, though no eruption has yet occurred. Seismic activity at the volcano remains above background levels and has waxed and waned over the last week. Yesterday from 11:18 to about 16:00 AKST, there were several periods of more intense seismic tremor. Since then, nearly continuous low-level seismic tremor has been recorded.
Clear web camera images currently show no activity at the volcano. Observers on overflights during the past week reported intermittent steam plumes from the area of the 1989-90 lava dome, continued melting of the upper Drift glacier, and increased water discharge along the lower Drift glacier and into the Drift River. Airborne gas measurements on January 31 and February 2 recorded levels of the magmatic gas CO2 several times greater than the value recorded on November 2, 2008.
Gas and heat flux, combined with ongoing seismic activity, suggest that new magma has been emplaced within the crust below Redoubt and that it is actively degassing. We do not know the exact depths or volume of the magma; nor is it certain that the magma will continue to rise to the surface. On the basis of current activity, however, the most likely scenario is an eruption similar to or smaller than the 1989-90 eruption. It is somewhat less likely that no eruption will occur or that the volcano has an eruption larger than that of 1989-90.
AVO personnel installed two new seismic instruments near Redoubt over the past week, and improved signals coming in from the Redoubt seismic network at AVO's facility in Homer.
