ALASKA VOLCANO OBSERVATORY INFORMATION STATEMENT
U.S. Geological Survey
Friday, January 26, 2024, 8:44 AM AKST (Friday, January 26, 2024, 17:44 UTC)
Following the initial installation of a single temporary seismic and geodetic station on Kruzof Island in May 2022, the Alaska Volcano Observatory (AVO) installed an expanded, permanent local monitoring network at Edgecumbe in July 2023. The network consists of 4 seismic stations and 4 global navigation satellite system (GNSS) sites measuring ground deformation on Kruzof Island. There is also an additional seismic station in Sitka, 24 km (15 miles) to the east of the volcano that is operated by the National Tsunami Warning Center. This network expansion has improved our ability to observe volcanic activity and accurately locate earthquakes and measure ground deformation. After an evaluation period following the 2023 field season, AVO now considers the new network sufficiently reliable to confidently monitor seismic unrest at Edgecumbe, AVO’s main criterion to set an Alert Level and Color Code status. With the establishment of robust monitoring data, Edgecumbe is being moved from UNASSIGNED to Volcano Alert Level NORMAL and Aviation Color Code GREEN.
Update on long-term low-level activity at Mount Edgecumbe
Edgecumbe is monitored by local seismic and GNSS sensors, satellite data, a web camera, and remote infrasound and lightning networks.
Mount Edgecumbe is a 976 m (3202 ft) high stratovolcano on Kruzof Island located 24 km (15 mi) west of Sitka, Alaska, and is part of a broader volcanic field of lava domes and craters on southern Kruzof Island and surrounding submarine vicinity. There are no written observations of eruptions from the volcanic field; Tlingit oral history describes small eruptions from about 800 years ago. Geologic investigations show that eruptions 13,000 to 14,500 years ago produced at least one widespread regional tephra layer around 1 m thick near Sitka and over 30 m thick on parts of Kruzof Island. Smaller eruptions occurred between 6,000 and 4,000 years ago. The volcanic field has erupted a wide range of basalt to rhyolite compositions from numerous vents over the past 600,000 years. The primary hazards of past eruptions, and thus likely in future eruptions, have been volcanic ash emissions producing local and region ashfall and drifting ash clouds. Volcanic lahars (debris flow or sediment-rich debris flows), pyroclastic flows (hot rock avalanches), and lava flows have also occurred on the flanks of Mount Edgecumbe. Mount Edgecumbe and the surrounding volcanic field lies within the Tongass National Forest.
Matt Haney, Scientist-in-Charge, USGS firstname.lastname@example.org (907) 786-7497
David Fee, Coordinating Scientist, UAFGI email@example.com (907) 378-5460
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.