Alaska Volcano Observatory

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 

• Low-level unrest at Mount Edgecumbe continues and is consistent with magma intrusion at deep levels in the Earth’s crust (greater than six miles below sea level).    
• The rate of ground uplift has declined to about 2–3 cm/year (0.8–1.2 inches/year).   
• Low numbers of primarily small earthquakes continue, and AVO is now able to detect and locate earthquakes smaller than magnitude 1 with the new network.  
• No anomalous volcanic gases have been detected. 
• Additional signs of volcanic unrest would likely occur prior to an eruption as magma rises to the surface. Some magma intrusions do not erupt.

Edgecumbe is monitored by local seismic and GNSS sensors, satellite data, a web camera, and remote infrasound and lightning networks.