1,939 Years Ago This Week, Vesuvius Erupts

On the left, a contemporary view of Vesuvius in 79 AD, as seen in artwork in a Pompeiian villa. They had no idea it was a volcano.

On the right, Vesuvius after the eruption, as seen from an excavated Pompeii. That bump on the right is all that remains of the former structure. The double-peak cone formed during the 79 AD eruption.

Pliny the Younger to Cornelius Tacitus, soon after the disaster:

Thank you for asking me to send you a description of my uncle’s death so that you can leave an accurate account of it for posterity(1); I know that immortal fame awaits him if his death is recorded by you. It is true that he perished in a catastrophe which destroyed the loveliest regions of the earth, a fate shared by whole cities and their people, and one so memorable that is likely to make his name live for ever: and he himself wrote a number of books of lasting value: but you write for all time and can still do much to perpetuate his memory. The fortunate man, in my opinion, is he to whom the gods have granted the power either to do something which is worth recording or to write what is worth reading, and most fortunate of all is the man who can do both. Such a man was my uncle, as his own books and yours will prove. So you set me a task I would choose for myself, and I am more than willing to start on it.

My uncle was stationed at Misenum, in active command of the fleet.(2) On 24 August, in the early afternoon, my mother drew his attention to a cloud of unusual size and appearance. He had been out in the sun, had taken a cold bath, and lunched while lying down, and was then working at his books. He called for his shoes and climbed up to a place which would give him the best view of the phenomenon. It was not clear at that distance from which mountain the cloud was rising (it was afterwards known to be Vesuvius); its general appearance can be best expressed as Continue reading


Kilauea Update

There has been a slight, but possibly very important, change in the eruption–less lava coming out in the Lower East Rift Zone and a hiatus in summit collapse events–and I’m updating the Kilauea eruption page again. Can’t spend a lot of time on it because of book work, but I’ll try to catch the important stuff. Right now it’s mostly waiting to see the next pronouncement from USGS/HVO.

Click the link at the upper right of this page or use this one.

You’ve seen plenty of video of the lava flowing in the LERZ, so here is a USGS video of a summit collapse event about two months into the eruption. It’s not dramatic to look at–just trees shaking as the seismic waves roll through–but it is every bit as much of a caldera collapse as something CGI’d in a supervolcano movie.

Only it’s in real life, and happening so slowly that we can watch it in relative safety, while carrying on with our lives as usual nearby. And there hasn’t been one of these otherwise daily occurrences since August 2nd; it may never happen again our lifetime. (Then again, it might–you can’t be sure of anything around Pelee!)

Featured image: USGS/Hawaiian Volcano Observatory

Alaska’s Sitkin Volcanoes

You might already have heard of one of the two Alaskan “Sitkin” volcanoes, since headline writers at a few news websites are giving Great Sitkin Volcano the “about-to-explode” treatment.

Indeed, the Alaska Volcano Observatory (AVO) recently raised the aviation code on Great Sitkin Volcano to Yellow, since it is having a period of elevated seismicity.


Great Sitkin has been having swarms of small earthquakes off and on since 2016. There also was a small ash emission in early June.

Magma probably has moved into the volcano. But there is no sure way to predict exactly what Great Sitkin Volcano will do in coming weeks and months, as volcanologists told local journalists late last year.

Instead of going by the doom-and-gloom headlines, let’s get to know these volcanoes a little better.

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Livestream of Kilauea’s Summit Crater

The lava fountains and human drama in Hawaii’s Lower Puna District are getting all the headlines, but geologists know there is also drama ongoing at the summit, where the volcano’s crater seems to have been slowly collapsing since the lava lake drained.

Hawaiian Volcano Observatory staff were forced to move farther away from the summit area because the many earthquakes there were damaging the building. Now, they have set up a livestream, and it’s fascinating to watch. Basically, the crater walls are slowly crumbling inward, and there is a pile of rocks at the bottom that may be suppressing the explosions — after a period of suppression, of course, there will likely be a big steam blast to relieve pressure, But no one knows if or when that will happen, or what will happen next.

Anyway, here’s the livestream:

For comparison, here’s a video they recorded in March to mark the ten-year anniversary of the lava lake first appearing in the summit crater. Where he’s standing has already collapsed now.

Here is a drone overlight of Halemaumau they did on May 31st. As you can see, the vent where the lava lake used to be has expanded to almost fill the whole crater. And there’s the rock pile down at the bottom, probably supressing, to some extent, the explosions.

And, about an hour ago, the USGS posted this:


Featured image: USGS. Those curved lines on the left is where the visitor’s parking lot used to be.

June 3, 2018, Fuego Eruption

July 18, 2018: I had to back off from the horror of this disaster, even though I don’t know anyone involved; volcanoes are beautiful, but they are so dangerous and they can change your world so quickly, yet so impersonally. Feeling better able to cope with this now and send love and encouragement to all Guatemalans. Here is an overview of things currently, from “The Guardian”:

June 10, 2018: It has been a week, and this is the last update, although the anonymous heroes continue to work in the midst of hot pyroclastic flow deposits, ongoing activity at the volcano, and tropical heat.

Per CONRED today, 197 are still missing, 110 are dead, and a total of 132 are injured (I don’t know the difference between damnificadas and heridas). Some 12,600 people are still evacuated and almost 4,500 people are homeless (though some have gone to stay with nearby relatives).

June 4: This is an amazing picture:


Now the hard news.

As of 5 p.m. local time, CONRED in Guatemala reported these figures:

  • 65 dead. This will probably rise, as rescue efforts reportedly were interrupted by a second eruption today, as well as a landslide.
  • 46 injured
  • 1.7 million people affected
  • 3,271 people evacuated and cared for
  • 1,916 people in shelters
  • 1 airport affected
  • 2 power grids affected
  • 1 bridge destroyed

Original post from June 3 follows.

I just heard about this.


Officially, at least 6 dead and tens of people injured. The Guardian reports multiple fatalities. (Update: At least 25 dead, hundreds injured. Per Reuters, “Officials said the dead were so far all concentrated in three towns: El Rodeo, Alotenango and San Miguel los Lotes.” The “lava” overflowing its banks s/l either a pyroclastic surge or a huge lahar, probably the former; doubt it was actually lava.)

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Guest Videos: Monitoring Volcanoes With Cosmic Rays

You might have heard that they found another chamber in the Great Pyramid recently. Archaeologists and physicists did this by using muons–a type of subatomic particle–to see inside the rock.

Here’s how they did it:

There is another way muon tomography is helping scientists keep people safe: by looking through volcanoes.

This is cutting edge stuff, and work still continues at Soufrière Guadeloupe, where at least five working telescopes were in place in February 2017.

Unfortunately, the last online bulletin of the volcano observatory at Guadeloupe (English translation of website here) is from 2014.

I hope the Great Pyramid discovery may encourage more volcanologists around the world to check out the technique!

Hawaiian Volcanoes: The Big Island 5

Those of us outside Hawaii may be a little off in our perception of the ongoing eruption at Kilauea Volcano:

The image on the left makes sense to anyone who has heard that the Big Island sits on a geological hot spot where molten rock leaks out of Earth’s mantle, forming a series of shield volcanoes.

What we’re missing is the fact that two different local macrofeatures–this mantle hot spot and the Pacific Ocean crust underlying Hawaii–are in constant motion relative to each other. With magma constantly upwelling from below, the end result is less like a conveyor belt of “Hershey’s Kiss” volcanoes and more like what happens when you try to spoonfeed an infant for the first time.

This is how, over the last million years or so, a total of five volcanoes have piled up above the waves together (with some help from submarine volcanoes Mahukona and Loihi) to form the Big Island.

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Guest Video: “Hell on Earth…”

h/t to Dr. Brad Pitcher’s tweet for this. Also, remember this video if you are ever exposed to volcanic ash- try not to breathe it in.

Mount St. Helens is much more peaceful these days:


Featured image: Srosenow 98, CC BY 2.0