Eruptions Newsletter #24 for December 5, 2025

We’ve already reached December and the end of the fall semester (for me). [Insert pithy remark about exhaustion].

Activity News

Hayli Gubbi, Ethiopia

Likely the most interesting eruption in the past few weeks was the (mostly) unexpected eruption of Hayli Gubbi in Ethiopia. I wrote an Eruptions Extra about the blast, but the long and short was the first historical eruption from this East African Rift volcano that is just southeast of Erta Ale. The blast coated much of the region for hundreds of kilometres to the east and north of Hayli Gubbi with a dusting of ash. This included parts of Saudi Arabia and Yemen across the Red Sea.

In the almost two weeks since the eruption nothing else has occurred at the remote volcano. Post-eruption images show new pit craters that formed during the blast (see above), but there is no evidence of lava flows or lava lake formed due to this new activity.

The ash from the November 23 eruption drifted to the northeast and did end up disrupting air traffic as far away as India. More locally, villagers living near Hayli Gubbi needed to be treated for ash inhalation and much of the grass and water for livestock has been contaminated.

As for what is next … that’s a great question. Recent research suggested that a dike of basalt magma has been intruding under the area, much like what is happening on the Reykjanes Peninsula in Iceland (see more on this below). However, the rates of intrusion are much lower, so Atalate Adele from the University of Addis Ababa suggests that we could see a few more eruptions, then a return to quiet.

Puracé, Colombia

In Colombia, Puracé was moved to orange alert status after a new explosive eruption on December 3. Now, somehow I had missed that Puracé had come back to life earlier this year (as did the media with all these “first eruption in decades” headlines), but it has now had a couple periods of explosive activity since its reawakening in 2022.

On December 3, the volcano produced a fairly impressive (but only 700 meter) ash plume that dusted towns as far as 10-12 kilometres from Puracé. The explosion was preceded by increased seismicity during late November. Puracé is a popular hiking destination with the Cinturo Andino (UNESCO Bioreserve), so the heightened alert could impact tourists as well as the ~335,000 people who live within 30 kilometres of the volcano. Colombian authorities are making plans for potential evacuations of at least 1,500 people living near Puracé if the eruptions worsen.

Kīlauea, Hawai’i

Over in Hawai’i, Kīlauea had its 37th eruptive episode on November 25. It was relatively tame by the standards of the activity at Kīlauea this year, but then again, can you call any event that fountains 1200C lava 180 meters into the air “tame”? The eruption lasted 9 hours with only the north vent really producing lava fountains. The USGS Hawaiian Volcano Observatory suggested that based on current inflation rates, the next eruption could be between December 6-10.

Sundhnúkur, Iceland

In the opposite of activity news, the eruptions on the Reykjanes Peninsula near Grindavík are in the midst of the longest break between eruptions. Assuming a new eruption hasn’t started by Friday, 120 days have passed since the last eruption in the region that saw spates of lava erupting since December 2023.

That being said, the Icelandic Meteorological Office still thinks a new eruption is in the works. Inflation has continued with almost 17 million cubic meters of new magma accumulating under the area.

Bur Ni Telong, Indonesia

Bur Ni Telong is not a well-known volcano outside of Indonesia, but it is a popular destination for climbers. Indonesia official recently raised the alert status at Bur Ni Telong after a nearby M4.3 tectonic earthquake (caused by movement on a fault) may have triggered increased volcanic seismicity at the volcano. Climbers had already been warned in early August of increasing signs of unrest at Bur Ni Telong, with officials closing the volcano to climbing. Currently, people have been told to stay 1.5 kilometres away from the crater area. The last known eruption from Bur Ni Telong was in 1937, albeit a very small event. A VEI 2 eruption (still pretty small) occurred in 1919 as well.

Volcano Research of the Week

The Black Death! It was one of Europe’s most devastating periods of history, killing possibly as much as 60% of the population. Although we think of “the plague” being long ago, it actually lasted until the early 19th century. That’s almost 600 years from its first major emergence in Europe in the mid-1300s.

A new study in Nature Communications: Earth & Environment by Martin Bauch and Ulf Büntgen suggests that the onset of the Black Death in Europe may have been a confluence of social and environmental factors that was triggered by … volcanic activity!

European trade around the Mediterranean and East Asia was complicated in the early 1300s. The Mongol Horde controlled much of eastern Asia around the Black Sea and the Pope banned trade with many countries across the eastern Mediterranean. Some of the big city-states in Italy like Genoa, Venice and Pisa had begun building trade networks that stretched far across the region.

Bauch and Büntgen posit that a famine triggered by cold winters and summers in the northern hemisphere in the late 1340s/early 1350s started a series of events that brought the plague to Italy and then across Europe. Grain needed to feed people in Italy was imported from around the Black Sea. This meant fleas infected with the Black Death virus were likely transported from Kyrgyzstan. In fact, one of the first known cases of the plague in Venice occurred less than 2 months after the first shipment from the Black Sea region!

So, what eruptions are to blame? That’s the trickier part, right? Although there are clear records in tree rings, atmospheric observations and weather records that volcanic aerosols like sulfur dioxide were causing cooling, where was this smoking gun?

There aren’t a lot of great candidates in that time period — either because we don’t have good dates or we don’t have good volume estimates. Offering a little latitude to dates and VEI, some larger eruptions of the mid-to-late 1300s in the Global Volcanism Program’s Holocene Eruption database include

• Kaharoa eruptions from the Okataina Caldera in New Zealand (VEI 5 in ~1310, likely too old)

• Cerro Bravo in Colombia (VEI 4 in ~1330, potentially too small)

• Pelee on Martinique (VEI 4 in ~1340, potentially too small)

• Mono/Inyo Domes in California (VEI 4 in ~1350, likely not explosive enough)

• Kikhpinych in Russian Kamchatka (VEI 4 in ~1350, probably too far north)

• Nevado del Ruiz in Colombia (VEI 4 in ~1350, likely too small)

• Cotopaxi in Ecuador (VEI 4 in ~1350, likely too small)

• Katla in Iceland (VEI 4 in 1357, too recent)

• El Chichón in Mexico (VEI 5 in ~1360, maybe too recent)

• Oraefajókull in Iceland (VEI 5 in 1362, too recent)

Not the most promising list! For climate impact, you really want eruptions that are bigger (VEI 5+) and equatorial. Bauch and Büntgen estimate an eruption ~1345 that would match 1991’s Pinatubo eruption (VEI 6) and they suggest other climate-impacting eruptions occurred in 1329, 1336 and 1341 (with the first and last being out of the northern hemisphere tropics).

Where does that leave us? Maybe the date for El Chichón’s VEI 5 is too young — only needs to be off by about a decade potentially. Maybe the eruptions at Pelee, Cotopaxi or Nevado del Ruiz have been underestimated? Maybe some of the other eruptions that don’t have good VEI estimates were big (Pagan in the Mariana Islands, Kikai in Japan, Kambalny in Russia, Sabancaya or El Misti in Perú?)

I do enjoy a good “big eruption” mystery and based on this paper, there looks to be a good one for the mid-1300s. The eruption itself may not have left an obvious mark on the landscape, but the cascading effects of the blast could have been one of the biggest disasters in European history.

Odds & Ends

Speaking of Europe, NPR took a deep dive looking at the potential for new eruptions in Italy’s Campi Flegrei. It is definitely a more level-headed exploration than some of the breathless reports of unrest found in other news media (ahem, the Daily Mail).

Not level headed is the latest techbro “idea” (i.e., scheme, grift, lunacy). Palmer Luckey, the head of military drone manufacturer Anduril was quoted as saying that “vehicles that can maneuver through the crust of the earth the same way that submarines move through the water are going to be a huge deal.” Maybe he hasn’t seen The Core … or maybe he’s seen it too many times. Big dreams are great, but wow, I would assume we’ll be all dancing the Charleston on Mars before any of this happens. But techbros being techbros, Luckey says he has “working prototypes” … without adding any details. Gotta love vaporware.

Sounds of the Week

Ok, so, we are in the allowable Christmas song window, right? Of almost any Christmas song of my youth, this one stands out. I think the Boston area radio stations I listened to were reeeeally into it and I still love it. I apologise for nothing.

Questions? Comments? Thoughts? Feel free to leave a comment, send me a note or follow me on Bluesky (@erikklemetti.bsky.social).