Long Quiet Volcano Showed Activity As Alaska Cruise Season Begins

Mount Edgecumbe is a 3,202-foot volcano on Kruzof Island, 15 miles west of Sitka. Sitka is a frequent cruise stop for ships sailing along America's 49th state's coast; the 2022 cruise season in Alaska begins this weekend. Despite concerns about the Edgecumbe Volcano, Royal Caribbean, Carnival Cruise Line, Celebrity Cruises, and Norwegian Cruise Lines have all booked trips around Sitka.

Edgecumbe's Activity

(Photo : Image from Duncan Mariott)

Mount Edgecumbe is part of a larger volcanic complex that includes lava domes and craters on southern Kruzof Island and the adjacent underwater area. According to the USGS, there are no documented records of eruptions from the volcanic field; indigenous Tlingit oral history mentions modest eruptions from around 800 years ago. According to geologic research, explanations 13,000 to 14,500 years ago generated at least one extensive regional tephra deposit over 3 feet deep in Sitka and over 100 feet thick on sections of Kruzof Island. According to scientists, smaller eruptions are thought to have happened between 6,000 and 4,000 years ago. Over the last 600,000 years, the volcanic area has produced various basalt to rhyolite compositions from various vents.

Until today, the volcano was thought to be inactive. According to the Alaska Volcano Observatory (AVO), hundreds of tiny earthquakes were reported around Mount Edgecumbe beginning on Monday, April 11, 2022, according to the Alaska Volcano Observatory (AVO). The swarm had hundreds of tiny quakes, which were too small to be detected. However, this current swarm prompted an in-depth examination of ground deformation detected by radar satellite data during the previous seven and a half years.

Recent Discoveries

According to AVO, a large region of roughly 10.5 miles in diameter with surface uplift centered about 1.5 miles east of Mount Edgecumbe has been discovered by analyzing recent years. According to the data, the uplift started in August 2018 and has been continuing at a pace of up to 3.4′′/year in the deforming area till now. Since 2018, there has been a total deformation of around 10.6 inches.

The latest earthquake activity, which began on April 11, was remarkable in that it produced a large number of occurrences. Since 2020, only earthquakes of magnitude 3.0 or below have been observed beneath the volcano.

Also Read: USGS Still Monitoring 4 Active U.S. Volcanoes in Orange and Yellow Status  

Earthquake Synchronicity

The synchronicity of earthquakes and ground deformation in time and position shows that these indications are likely related to magma flow beneath Mount Edgecumbe rather than tectonic activity, according to AVO/USGS' complete examination of the stratovolcano. According to preliminary modeling, the deformation signal appears to be compatible with the intrusion of fresh magma material at roughly 3.1 miles below sea level. The earthquakes are most likely generated by strains in the crust induced by the intrusion and the significant uplift it causes.

Magma

Where that magma goes now is the big question. "New magma intrusions beneath volcanoes do not necessarily result in volcanic eruptions," AVO stated in a recent statement. "Without an eruption, Edgecumbe's deformation and seismic activity may halt." The deformation pattern will alter if the magma gets closer to the surface, and earthquake activity will increase. As a result, if an eruption were to occur, more signs would precede it, providing early warning."

A tsunami might be triggered by a powerful earthquake or volcanic eruption in this area.

Lacks Monitoring

Edgecumbe currently lacks a local volcanic monitoring network. According to the USGS, the National Tsunami Warning Center operates the nearest seismic station in Sitka. Weekly, new satellite radar observations become accessible. AVO has begun planning to expand present monitoring capabilities, potentially by placing sensors closer to the volcano, to enhance the frequency of data collected. Edgecumbe will be monitored by AVO utilizing current area seismic stations and satellite data.

Trends will be closely monitored by tour firms, the fishing sector, and local inhabitants in the Sitka area.

Unassigned

Edgecumbe has not yet received an Aviation Code or a Volcanic Activity Alert Level from the USGS. Yellow indicates that a volcano shows symptoms of high unrest above known background levels, while green suggests usual activity associated with a non-eruptive condition. An eruption is likely, with considerable volcanic ash emissions into the sky.

Cruise companies will continue to watch the volcano's progress and the potential impact on Sitka port visits. A Royal Caribbean excursion from the Ovation of the Seas cruise ship visited White Island off the coast of New Zealand in December 2019. The visit turned tragic when the volcano erupted, killing 22 people and wounding 25 more. While the volcano killed vacationers on the trip, the ship was far enough away from it to avoid any damage to it or the other passengers.

Monitoring Active Volcanoes

The USGS monitors 161 potentially active volcanoes in the United States, most of which are in Alaska. However, according to geological records, Alaska has numerous volcanoes; more than 130 volcanoes and volcanic areas have been active in the last 2 million years. Since the mid-1700s, 50 have been active, and AVO investigates them.

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