Lava Signs at Okmok Volcano

Okmok Activity – Color Code RED : Alert Level WARNING

Okmok Volcano Activity Notifications
by AVO

The eruption of Okmok Volcano continued throughout this week with persistent ash emissions rising from 15,000 to 25,000 feet. From July 19 to July 20 the color code was increased to red in response to a more vigorous eruptive episode which produced ash to 30,000 feet. Photographs and an overflight by Alaska Volcano Observatory staff on July 20 and 21 confirmed the existence of multiple vigorous vents on the caldera floor.

Photo of the Okmok eruption, July 24, 2008, taken from Ft Glenn on the east flank of Okmok Caldera. Picture Date: July 24, 2008. credit : Lonnie Kennedy – Source: AVO

Seismicity was characterized by intermittent bursts of volcanic tremor early in the week. This changed to continuous mid-level volcanic tremor on July 23, which persists to the current time. Amplitude of tremor has been generally constant since July 21.

Although there has been little change in the eruption in the past several days, stronger explosive activity could resume at any time with little or no warning.

AVO Weekly Update – 2008-07-25 12:18:38

The eruption of Okmok Volcano continued throughout this week with persistent ash emissions rising from 15,000 to 25,000 feet. From July 19 to July 20 the color code was increased to red in response to a more vigorous eruptive episode which produced ash to 30,000 feet. Photographs and an overflight by Alaska Volcano Observatory staff on July 20 and 21 confirmed the existence of multiple vigorous vents on the caldera floor.

Seismicity was characterized by intermittent bursts of volcanic tremor early in the week. This changed to continuous mid-level volcanic tremor on July 23, which persists to the current time. Amplitude of tremor has been generally constant since July 21.

Although there has been little change in the eruption in the past several days, stronger explosive activity could resume at any time with little or no warning.

Cleveland Activity – Color Code ORANGE : Alert Level WATCH

Cleveland Volcano Activity Notifications

2008-07-25 12:18:38 – Weekly Update by AVO
Based on reports from fishing boats Cleveland Volcano began erupting at approximately 12:00 AKDT (20:00 UTC) on July 21, 2008. This eruptive episode is more intense than that observed over the past several years. Pilot reports and satellite data have documented a persistent low level ash emission from 10,000 to 20,000 feet throughout the week when the volcano was visible through clouds. A large thermal anomaly suggests the presence of an ongoing active lava flow.

Related Links:

• Video by AVO/USGS geologist Tina Neal during an overflight of the eruption of Okmok Volcano and distant ash plume from Cleveland Volcano. July 21, 2008.
• Okmok Eruption, Cleveland Volcano [Update #2]
• Explosive Eruption at Okmok Volcano [Update #1]
• Volcanoes