The shaking, which began at 11:18 a.m., was "the most energetic" seismic activity at Redoubt in a week, observatory geologists said.
Three minutes into the episode, one of the seismometers positioned near Redoubt recorded an earthquake that lasted more than a minute.
Originally posted by freemindmine
Why on the Webicorders are some blue and others dark blue? Is the different Stations ?
[edit on 5/2/09 by freemindmine]
A burst of volcanic tremor occurred just after 3:00 PM this afternoon lasting for about 30 minutes and is continuing at a sustained but lower level. This did not result in any eruptive activity and no ash emission has occurred.
AVO is monitoring and evaluating the situation closely.
Redoubt is still at aviation color code ORANGE and volcano alert level WATCH
Seismic tremors and rattling earthquakes shook Mount Redoubt for about 20 minutes this afternoon but haven't yet produced an eruption, according to the Alaska Volcano Observatory.
Commencing at 3:07 p.m., the shaking was both stronger and longer than a four-minute-long episode that hit this morning -- which geologists had called "the most energetic" seismic activity at Redoubt in a week.
"There was probably a lot of gas venting" during the second episode, said observatory geologist Chris Waythomas.
While Web cameras and satellite images were obscured by clouds throughout the day, radar and pilot observations confirmed that no eruption had occurred, he said.
REDOUBT VOLCANO (CAVW #1103-03-)
60°29'7" N 152°44'38" W, Summit Elevation 10197 ft (3108 m)
Current Aviation Color Code: ORANGE
Current Volcano Alert Level: WATCH
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.
Staff continue to monitor the volcano 24 hours a day. We will issue further information as it becomes available.
Heavily ice-mantled Redoubt volcano is located on the western side of Cook Inlet, 170 km (106 mi) southwest of Anchorage and 82 km (51 mi) west of Kenai, within Lake Clark National Park. Redoubt is a stratovolcano which rises to 10,198 feet above sea level. Recent eruptions occurred in 1902, 1966-68, and 1989-90. The 1989-90 eruption produced mudflows, or lahars, that traveled down the Drift River and partially flooded the Drift River Oil Terminal facility. The ash plumes produced by the 1989-90 eruption affected international air traffic and resulted in minor or trace amounts of ash in the city of Anchorage and other nearby communities.