AVO has observed a gradual increase in volcanic unrest over a period of several months at Mount Spurr, located about 120 km (75 miles) west of Anchorage (https://avo.alaska.edu/image/view/196123). GNSS receivers have detected sustained upward and outward ground deformation since March 2024. An increase in seismic activity has also been noted since April (https://avo.alaska.edu/image/view/196122). Other indications of elevated activity include the development of a small lake in the summit crater in early summer of 2024.
The largest magnitude earthquake detected in this current period of unrest is a M2.3 earthquake on October 6th. This increase in activity was described in detail in an Information Statement (https://avo.alaska.edu/news/hans/DOI-USGS-AVO-2024-10-09T19:43:26+00:00) that AVO released on October 9th. Analysis of seismic data indicates a subtle increase in the rate and size of earthquakes over the past few weeks. Because this is a notable departure from the normal background seismicity of the volcano, AVO is raising the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. However, there are no indications that an eruption is imminent. Often this type of seismicity and ground deformation will decline without producing an eruption.
AVO continues to closely monitor activity at Mount Spurr for signals that would indicate that the volcano is moving closer to an eruption. Based on previous eruptions, changes from current activity in the earthquakes, ground deformation, summit lake, and fumaroles would be expected if magma began to move closer to the surface. Therefore, it is very likely that if an eruption were to occur it would be preceded by additional signals that would allow advance warning.
Mount Spurr volcano is an ice- and snow-covered stratovolcano located on the west side of Cook Inlet approximately 120 km (75 mi) west of Anchorage. The only known historical eruptions occurred in 1953 and 1992 from the Crater Peak flank vent located 3.5 km (2 mi) south of the summit of Mount Spurr. These eruptions were brief, explosive, and produced columns of ash that rose up to 20 km (65,000 ft) above sea level and deposited several mm of ash in south-central Alaska, including approximately 6 mm (1/4 in) of ash on Anchorage in 1953. The last known eruption from the summit of Mount Spurr was more than 5,000 years ago. Primary hazards during future eruptions include far-traveled ash clouds, ash fall, pyroclastic flows, and lahars or mudflows that could inundate drainages all sides of the volcano, but primarily on the south and east flanks.
Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497
David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (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.
| (1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) | |
| (2) Issued: | (20241016/2007Z) |
| (3) Volcano: | Spurr (VNUM #313040) |
| (4) Current Color Code: | YELLOW |
| (5) Previous Color Code: | GREEN |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2024/A675 |
| (8) Volcano Location: | N 61 deg 17 min W 152 deg 15 min |
| (9) Area: | Cook Inlet-South Central |
| (10) Summit Elevation: | 11070 ft (3374 m) |
| (11) Volcanic Activity Summary: |
AVO has observed a gradual increase in volcanic unrest over a period of several months at Mount Spurr, located about 120 km (75 miles) west of Anchorage (https://avo.alaska.edu/image/view/196123). GNSS receivers have detected sustained upward and outward ground deformation since March 2024. An increase in seismic activity has also been noted since April (https://avo.alaska.edu/image/view/196122). Other indications of elevated activity include the development of a small lake in the summit crater in early summer of 2024. The largest magnitude earthquake detected in this current period of unrest is a M2.3 earthquake on October 6th. This increase in activity was described in detail in an Information Statement (https://avo.alaska.edu/news/hans/DOI-USGS-AVO-2024-10-09T19:43:26+00:00) that AVO released on October 9th. Analysis of seismic data indicates a subtle increase in the rate and size of earthquakes over the past few weeks. Because this is a notable departure from the normal background seismicity of the volcano, AVO is raising the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. However, there are no indications that an eruption is imminent. Often this type of seismicity and ground deformation will decline without producing an eruption. AVO continues to closely monitor activity at Mount Spurr for signals that would indicate that the volcano is moving closer to an eruption. Based on previous eruptions, changes from current activity in the earthquakes, ground deformation, summit lake, and fumaroles would be expected if magma began to move closer to the surface. Therefore, it is very likely that if an eruption were to occur it would be preceded by additional signals that would allow advance warning. |
| (12) Volcanic cloud height: | Unknown |
| (13) Other volcanic cloud information: | Unknown |
| (14) Remarks: | Mount Spurr volcano is an ice- and snow-covered stratovolcano located on the west side of Cook Inlet approximately 120 km (75 mi) west of Anchorage. The only known historical eruptions occurred in 1953 and 1992 from the Crater Peak flank vent located 3.5 km (2 mi) south of the summit of Mount Spurr. These eruptions were brief, explosive, and produced columns of ash that rose up to 20 km (65,000 ft) above sea level and deposited several mm of ash in south-central Alaska, including approximately 6 mm (1/4 in) of ash on Anchorage in 1953. The last known eruption from the summit of Mount Spurr was more than 5,000 years ago. Primary hazards during future eruptions include far-traveled ash clouds, ash fall, pyroclastic flows, and lahars or mudflows that could inundate drainages all sides of the volcano, but primarily on the south and east flanks. |
| (15) Contacts: | Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497 David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460 |
| (16) Next Notice: | |