Many times, the volcanoes that have eruptions that last decades are ones like Kīlauea in Hawai’i, Yasur in Vanuatu or Erebus in Antarctica, where hot, runny basalt continuously erupts in lava lakes. However, when you look at the Global Volcanism Program’s list of current eruptions, a few more explosive volcanoes jump out — in particular, Shiveluch in eastern Russia.

Since 1999, the volcano has been producing frequent lava domes that then are spectacularly destroyed in massive explosions. In a bit of a “lather-rinse-repeat” pattern, Shiveluch just keeps on going decade after decade. You can see the before and during eruption on November 7-8 in the Terra and Aqua images above. Brown and grey ash is covering much of the peninsula to the east of the volcano. Another image (below) taken by Sentinel-2 (false color) shows some of the fresh ash fall and pyroclastic material as well as the dome itself.

The current explosive eruptions from Shiveluch are coming from the newest dome, dubbed the “300 Years of RAS (Russian Academy of Science)” Dome (top). It is a pile of silica-rich lava that is oozing out in the crater created by a collapse of Shiveluch in its recent past. As it extrudes, pressure builds behind the lava and occasionally the dome plug fails and an explosion happens. This means a tall ash plume that rapidly spread east (depending on the winds).

Why is Shiveluch Dangerous?

A little background on Shiveluch. Although it is so active and violently so, it isn’t particularly hazardous to people on the ground. That’s because only a little over 1,700 people live within 30 kilometers (~18.5 miles) of this remote volcano. Even if you extend that circle out to 100 kilometers (62 miles), it only encompasses ~11,000 people. For most of them, the biggest hazard is the nuisance of falling volcanic ash.

However, all those tall volcanic ash plumes can really cause some aviation hazards. Commonly, Shiveluch will throw ash over 8-15 kilometers above sea level. That’s ~30,000 to 50,000 feet, the same flight level of most commercial air traffic. That ash tends to blow to the east and northeast over the Pacific Ocean, meaning that airplanes coming and going between Asia and North America have to contend with the risk of flying through that ash even if right now many planes don’t enter Russian airspace. The plume captured by NASA’s Terra earth imaging satellite stretched over 500 kilometers eastward (above).

How Big is that Plume?

Now, on an image like the Terra shot, it is sometimes hard to conceptualize just how far that ash plume from Shiveluch spans. These dome explosions that Shiveluch experiences are not unique — in fact, quite a few volcanoes in the western United States could exhibit the same style of eruptions. So, to help understand how far these plumes could stretch and the potential hazards of these eruptions to North America, I superimposed the Shiveluch plume onto some volcanoes to see just what might happen.

The most likely volcano to have a Shiveluch-style eruption would be Washington’s Mount St. Helens. Both volcanoes have experienced partial collapses and the new activity at both places have been in the scar left by those blasts. The activity at Mount St. Helens from 2004-2008 wasn’t as violent as Shiveluch’s activity over the 21st century, but there is plenty of evidence that St. Helens has had such eruptions in its past.

An eruption on the scale of the current Shiveluch activity from Mount St. Helens would have an ash plume spanning into central Idaho (assuming similar wind patterns, which isn’t out of the question). Now, this is just the visible after right after the blast, so that ash would continue east. Just like in 1980, you could easily image ash falling in Yakima, Spokane, Pullman and all along the Columbia River gorge depending on exactly what the wind is doing.

We have had experience with St. Helens ash in 1980, but what about in places that we haven’t experienced? The Lassen Volcanic Center in Northern California produced a series of silica-rich lava domes only 1,100 years ago from Chaos Crags. If you place the Shiveluch plume there, it reaches into western Utah. Reno, Winnemuca, Lake Tahoe and even Salt Lake City could all easily see significant ash fall as well.

Moving south, the Clear Lake Volcano north of the Bay Area has seen domes form. Most of these eruptions appear to have been less explosive than Shiveluch, but at least one major explosive event happened hundreds of thousands of years ago. Looking at that ash plume, it would cover much of the northern Sacramento Valley, including Sacramento, likely impacting Reno as well as it reaches into the middle of Nevada.

Finally, if the Salton Buttes, a group of rhyolite domes found in Southern California, produced a Shiveluch-scale explosive eruption, we might see the most significant impact in terms of people affected. Salton Buttes last erupted only a few thousand years ago, but an ash plume like what is happening today at Shiveluch would potentially drop ash on Phoenix, Tucson and Mexicali, reaching into western New Mexico.

This is not to say this scale of explosive eruption is likely in our lifetime from any of these volcanoes. However, what this does show is both the scale of the current activity at Shiveluch … thankfully located in a remote location where much of the ash ends up in the ocean. It also shows that our own volcanoes that could erupt like Shiveluch would mean some real disruptions to life for people across the western United States.