Things are really rumbling in Alaska, where scientists have upgraded Redoubt volcano to "orange" status, with an eruption possible within the next few hours or days. Earlier, earthquakes and tremors rattled the Cook Inlet area.
Redoubt last erupted in 1989-1990. Surging mud flows flooded the Drift River Oil Terminal Facility, while ash plumes disrupted air traffic as far away as Texas.
Located about 100 miles southwest of Anchorage, Redoubt's peak is 10,197 feet high. Its prior eruption coated Anchorage and nearby communities with ash, affecting air traffic and other transportation.
The Alaska Volcano Observatory is closely monitoring Redoubt. Today's report included this data:
The current activity at Redoubt could be precursory to an eruption, perhaps within days. A further increase in seismicity is expected to accompany an eruption. Staff are currently monitoring the volcano 24 hours a day.
.....Beginning at 00:58 AST (9:58 UTC) yesterday morning, nearly continuous volcanic tremor was recorded at stations near Redoubt's summit, prompting AVO to raise the Aviation Color Code to ORANGE and the Alert Level to WATCH at 02:09 AST (11:09 UTC). AVO had raised the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY on November 5, 2008, in response to increased emissions of volcanic gases; melting of snow and ice near the volcano’s summit; and a subtle increase in seismicity.
NASA's Earth Observatory program provides monitoring and studies of natural disasters. Special sensors on NASA satellites, including the Aqua craft, were used to monitor the flow and dangers of Redoubt's ash plume.
Researchers Simon A. Carn, Arlin J. Krueger, Nickolay A. Krotkov, Kai Yang, and Keith Evans reported:
The 1989–1990 eruption of Redoubt (Alaska) provided perhaps the earliest indication that even aged, dilute volcanic clouds are an aviation hazard. Two encounters with the December 15, 1989 volcanic cloud from Redoubt occurred on December 17 over western Texas, when the cloud was 35–55 h old and had drifted *5400 km from the volcano (Casadevall 1994). Elevated SO2 was detected by N7-TOMS over Nevada and eastern California on December 16 and off the coast of Baja California on December 17 (Schnetzler et al. 1994). The December 17 encounters involved the loss of power to one engine on a Boeing 727 bound for El Paso, Texas, and minor leading edge abrasion on a US Navy DC-9 departing the El Paso area, both due to volcanic ash
Image credit: Redoubt's 1989 eruption, photographed by W. White of the USGS
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