Volcano Update from Archive
FOURPEAKED VOLCANO (VNUM #312260)
58°46'13" N 153°40'26" W, Summit Elevation 6903 ft (2104 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN
The Alaska Volcano Observatory (AVO) has experienced failures of all monitoring instruments and stations at Fourpeaked Volcano and can no longer seismically monitor unrest at this volcano. As a result AVO may is unable to (1) assess whether this volcano is may be building towards and eruption and (2) quickly confirm or dismiss reports of activity. Because this volcano is no longer seismically monitored, it will move from volcano alert level Normal and Aviation color code Green to "unassigned". As at other volcanoes without real-time seismic networks, AVO will continue to use satellite data, infrasound and reports from pilots and ground observers to detect signs of eruptive activity.
Fourpeaked Volcano is located on the Alaska Peninsula about 200 miles (325 km) southwest of Anchorage, Alaska in the Katmai National Preserve. Fourpeaked Volcano has no reported historical eruptions. Increased steaming was reported near the summit in 1965. On September 17, 2006 Fourpeaked was the site of water generated explosions that produced plumes of steam and volcanic gas that rose to altitudes of 20,000 ft above sea level. These plumes were visible from communities on the Kenai Peninsula. Subsequent ground observations of the volcano revealed a linear series of vents extending north from the summit of the volcano for about 1 km.
AVO has also experienced numerous station failures at Fisher, Shishaldin, Westdahl and Gareloi volcanoes and many of the stations that continue to work provide data only intermittently. Because we have lost the capacity to reliably identify and locate earthquakes and other seismic indicators of unrest, our ability to monitor volcanic activity and forecast eruptions in advance at these volcanoes is heavily impaired. These volcanoes remain on our list of seismically monitored volcanoes at this time because we maintain a minimal capability to detect anomalous activity through intermittent data transmission or at least one functional station. Although we may be able to detect an eruption seismically, we may not be able to identify precursory seismicity and provide advance warning.
The status of the impaired networks may change in coming weeks and months. Seismic stations are partially solar-powered and some may resume operating as daylight hours increase in the spring. AVO will continue to attempt repairs as conditions permit. We will update this information statement as appropriate, or if it becomes clear that we can no longer seismically monitor a volcano at all.
We continue to monitor all Alaskan volcanoes with satellite and regional infrasound data. In addition some volcanoes also are monitored with real-time GPS and webcams. Although we cannot forecast eruptions with these data, we may detect eruptions with a delay of tens of minutes to hours in some cases. However poor weather, common in the North Pacific, can also prohibit detection of significant eruptions using these alternate data sources.
John Power, Scientist-in-Charge, USGS
email@example.com (907) 786-7497
David Fee, Acting Coordinating Scientist, UAFGI
firstname.lastname@example.org (907) 322-4085
The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.