Alaska's Pavlof Volcano recently began erupting in the Aleutian Island chain, 592 miles southwest of the city of Anchorage.
It has been an active one in general. This volcano erupted more than 40 times in the history of measuring such geological action, and is one of the Aleutian Arc's most active volcanoes. Pavlof is covered in snow and ice, and is located on an arc of active and dormant volcanoes that extends into the Alaskan mainland and for the length of the Aleutian Island chain. It is a stratovolcano - meaning one that is built of alternating layers of lava and ash.
During the current eruption, ash flew 37,000 feet into the air, and Alaska Airlines canceled 10 flights out of Anchorage and their return legs. Mud flow is likely on the flanks of the volcano.
HNGN recently spoke with scientist Jessica F. Larsen, who is a professor of volcanology at the University of Alaska Fairbanks (UAF) and acting coordinating scientist at the Alaska Volcano Observatory (AVO), focusing right now on Pavlof.
Pavlof has erupted over 40 times. When was its first eruption recorded? Were previous eruptions clustered in time, and if so, how?
I think, probably, the most interesting time period for Pavlof eruptions is the "historical" time period, stretching back to the early 1800s. The first confirmed historical eruption occurred in 1817, as described in a report from the Lamont-Doherty Geological Observatory of Columbia University and NOAA.
There was an earlier eruption. Have you been expecting the current one for some time?
The last prior eruption period from Pavlof was in 2014. A period of time from May 31, 2014 to June 25, 2014, involved ash clouds to 22,000 feet above sea level on June 2. Then again, in November of that year, an eruption started Nov. 12 and escalated to ash clouds [of] 25,000 to 30,000 feet on Nov. 15-16. That eruption subsided by Nov. 25.
The current eruption began Sunday, March 27, just before 4 p.m. AKDT, with an abrupt onset, and sharply increased with accompanying seismicity. Although this event was surprising given the lack of a warning sign in terms of precursory seismicity, Pavlof Volcano is so frequently active I would not say it was totally unexpected.
How many volcanoes in the Aleutians are consistently active?
There are 52 active volcanoes in Alaska. We have on average one to three eruptions per year (in approximately 25 years on record).
Does your work involve keeping tabs on all Aleutian volcanic activity? How long have you been doing that yourself, and does it include monitoring all seismology too?
I work with the Alaska Volcano Observatory through the UAF Geophysical Institute partner agency. I have worked for AVO since summer 1997, almost 19 years now. The AVO collectively monitors activity from 27 volcanoes, meaning those volcanoes have some level of seismic monitoring. The remainder are observed using remote methods, including satellite remote sensing and infrasound activity. Infrasound is detection of sound waves emanating from volcanoes, typically in the form of explosions.
Is the community of Cold Bay, 37 miles from Pavlof, ever affected by its eruptions?
Depending on the direction of the wind, it is possible for ash fall to impact Cold Bay from Pavlof Volcano. There is a record of ash impacting Cold Bay to some extent during 2014, and I provide a link to an article about it.
Is there anything else you'd like to say about Pavlof or the Aleutian volcanoes in general?
Many people living outside of Alaska know maybe a little about our volcanoes, or the fact that we have so many active volcanoes. But, I am not sure it is well-known that we have 52 active volcanoes and an average eruption rate of one to three per year.
Also, there are approximately 50,000 people in commercial airliners traversing the North Pacific air routes (typically from North America to Asia). So, apart from the ground-based hazards to Alaskan residents typically from ash fall, aviation safety concern here is a large issue, and Alaska Volcano Observatory fulfills an important public safety mission for people living near our active volcanoes as well as regional, national and international air traffic.
