The pressure cooker

It will come as no surprise to regular readers of Skeptophilia that I have a peculiar fascination for things that are huge and powerful and can kill you.

I'm not entirely sure where this obsession comes from, but it's what's driven me to write here about such upbeat topics as giant predatory dinosaurs, tornadoes, hurricanes, massive earthquakes, supernovas, gamma-ray bursters, and the cheerful concept of "false vacuum decay" (which wouldn't just destroy the Earth, but the entire universe).  I'm guessing part of it is my generally anxiety-ridden attitude toward everything; after all, just because we don't think there's a Wolf-Rayet star nearby that's ready to explode and fry the Solar System doesn't mean there isn't one.  I know that worrying about all of that stuff isn't going to (1) make it any less likely that it'll happen, or (2) make a damn bit of difference to my survival if it does, but even so I don't seem to be able to just relax and focus on more positive things, such as the fact that with the sea-level rise predicted from climate change, it looks like here in upstate New York I may finally own ocean-front property.

It's also why I keep regular tabs on the known volcanoes on the Earth -- on some level, I'm always waiting for the next major eruption.  One of the potentially most dangerous volcanoes on Earth is in Italy, and I'm not talking about Vesuvius; I'm referring to the Campi Flegrei ("burning fields," from the Greek φλέγω, "to burn"), which isn't far away from the more famous mountain and seems to be powered by the same magma chamber complex that obliterated Pompeii, Herculaneum, and Stabiae in 79 C.E.  Both Vesuvius and the Campi Flegrei are highly active, and near the top of the list of "world's most dangerous volcanoes."

The problem is, the three million residents of Naples live right smack in between the two, only twenty-odd kilometers away from Vesuvius (to the east) and Campi Flegrei (to the west).  (For reference, Pompeii was nine kilometers from the summit of Vesuvius.)

The Campi Flegrei, looking west from Naples [Image licensed under the Creative Commons Baku, VedutaEremo2, CC BY-SA 4.0]

The problem is that volcanoes like these two don't erupt like the familiar fountains of lava you see from Kilauea on the Big Island of Hawaii, and the recent eruption on La Palma in the Canary Islands and the one near Grindavík in Iceland.  The most typical eruption from volcanoes like Vesuvius and Campi Flegrei are pyroclastic flows -- surely one of the most terrifying phenomena on Earth -- a superheated mass of steam and ash that rush downhill at speeds of up to a hundred kilometers an hour, flash-frying everything in its wake.  That the Campi Flegrei volcanoes are capable of such massive events is witnessed by the surrounding rock formation called the "Neapolitan Yellow Tuff."  A "welded tuff" is a layer of volcanic ash that was so hot when it stopped moving that it was still partially molten, and fused together into a solid porous rock.

A video of a pyroclastic flow from Mount Unzen in Japan in 1991

The Neapolitan Yellow Tuff isn't very recent; it came from an eruption about 39,000 years ago.  But there are signs the Campi Flegrei are heating up again, which is seriously bad news not only for Naples but for the town of Pozzuoli, which was built right inside the main caldera.  The residents of Pozzuoli have had to get used to regular rises and falls of the ground, some by as much as an alarming two meters.  In fact, between 1982 and 1984, there was so much uplift -- followed by magnitude-4 earthquakes and thousands of microquakes -- that the harbor became too shallow for most ships to dock, and the entire population of forty thousand was evacuated until things seemed to simmer down.

In fact, the reason the topic comes up is a study out of Stanford University and the University of Naples that appeared this week in the journal Science Advances, that found this terrifying swell-and-subside isn't due primarily to magmatic movement, as was feared -- it's the bubbling of superheated groundwater.  The study looked at the composition of the "caprock," the rock layer on top of the formation, and found that when mixed with hot water it forms something like a natural fibrous cement.  This then plugs up cracks and prevents groundwater from escaping.

The whole thing is like living on the lid of a giant pressure cooker.

Of course, unlike (I hope) your pressure cooker, the rock doesn't have the tensile strength to manage the pressure fluctuations, so ultimately it breaks somewhere, triggering an earthquake and steam eruptions, after which the caprock settles back down for a while until the cracks all reseal and the pressure starts to rebuild.

This is all pretty scary, but it does point scientists in a direction of how to mitigate its potential for harm.  "I call it a perfect storm of geology -- you have all the ingredients to have the storm: the burner of the system -- the molten magma, the fuel in the geothermal reservoir, and the lid," said Tiziana Vanorio, who co-authored the study.  "We can't act on the burner but we do have the power to manage the fuel.  By restoring water channels, monitoring groundwater, and managing reservoir pressure, we can shift Earth sciences toward a more proactive approach -- like preventive health care -- to detect risks early and prevent unrest before it unfolds.  That's how science serves society."

Which is all very well, but I still wouldn't want to live there.  I visited Italy last year and loved it, but the area around Naples -- that'd be a big nope for me.  When we were in Sicily, itself no stranger to seismic unrest, one of our tour guides said, "We might be taking a risk living here, I suppose.  But those people up in Naples -- they're crazy."

That anyone would build a town on top of an active volcano is explained mostly by the fact that humans have short memories.  And also, the richness of volcanic soils is generally good for agriculture.  Once Pompeii was re-discovered in the middle of the eighteenth century, along with extremely eerie casts of the bodies of people and animals who got hit by the pyroclastic flow, you'd think people would join our Sicilian tour guide in saying, "no fucking way am I living anywhere near that mountain."  But... no.  If you'll look at a world map, you might come to the conclusion that siting big cities near places prone to various natural disasters was some kind of species-wide game of chicken or something.

Not a game I want to play.  Such phenomena make me feel very, very tiny.  I'm very thankful that I live in a relatively peaceful, catastrophe-free part of the world.  Our biggest concern around here is snow, and even that's rarely a big deal; we don't get anything like the killer blizzards that bury the upper Midwest and Rocky Mountain states every year.  Given my generally neurotic outlook on life, I can't imagine what I'd be like if I did live somewhere that had serious natural disasters.

Never leave my underground bunker, is probably pretty close to the mark.

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When the volcano blows

If you were wondering what the final act of the 2020 fever-dream theater might be, I have a possible contender.

Geologists have just discovered another supervolcano besides Yellowstone.

Supervolcanoes -- known in scientific circles as caldera eruptions -- are insanely powerful.  The famous 1883 eruption of Krakatoa, in Indonesia, was a caldera eruption, but even that was on the small end of things; it blasted 25 cubic kilometers of ash and rock fragments into the air, while the last major eruption of Yellowstone (650,000 years ago) released forty times that much, and covered most of what is now the central United States in a meter or two of ash.

And Toba, another Indonesian volcano, released almost three times more than that, 74,000 years ago -- and some anthropologists think the resulting climate impact nearly wiped out the up-and-coming human race, by some estimates reducing the entire population of humans to only about a thousand individuals.

By comparison, the eruption of Mount Saint Helens in 1980 was pretty much a wet firecracker.

So anyhow, why this all comes up is because we thought we knew where most of the potentially huge calderas were located, and geologists have given a great effort to calming everyone down, saying we have a handle on things and will have plenty of warning if any of them show signs of an imminent eruption.

Turns out, we didn't even know one of them was there.

A cluster of six islands in the Aleutian chain -- Carlisle, Cleveland, Herbert, Kagamil, Chagulak, and Uliaga -- have long been known to be stratovolcanoes, conical, explosive volcanoes of the same type as Mount Vesuvius.  What scientists didn't know until now is that apparently, the magma reservoirs of these six islands are not separate blobs, but one enormous blob underlying the entire island chain.

Just like the one under Yellowstone.

Mount Cleveland [Image is in the Public Domain]

The findings, which will be formally presented at the meeting of the American Geophysical Union on Monday, are a little alarming.  According to the press release from Science Daily:

Researchers from a variety of institutions and disciplines have been studying Mount Cleveland, the most active volcano of the group, trying to understand the nature of the Islands of the Four Mountains.  They have gathered multiple pieces of evidence showing that the islands could belong to one interconnected caldera.

Unlike stratovolcanoes, which tend to tap small- to modestly-sized reservoirs of magma, a caldera is created by tapping a huge reservoir in the Earth's crust.  When the reservoir's pressure exceeds the strength of the crust, gigantic amounts of lava and ash are released in a catastrophic episode of eruption...

If the researchers' suspicions are correct, the newfound volcanic caldera would belong to the same category of volcanoes as the Yellowstone Caldera and other volcanoes that have had super-eruptions with severe global consequences.

So yeah.  That's just marvelous.  Okay, I know, the discovery doesn't mean it's going to erupt any time soon, although it bears mention that Mount Cleveland has erupted 22 times in the past 230 years, and eight of those eruptions were in the last eleven years.  So it would totally be on-brand for 2020 if the whole thing went kablooie.

Yes, I know, I'm not supposed to be superstitious or engage in magical thinking or anything.  Given how this year's gone, I think I deserve a little slack, here.  No one will be happier than me if January 1, 2021 comes and the Aleutian Islands still exist, but at present I'm not ruling anything out. 

There we have it -- a supervolcano that we didn't even realize existed.  Just another thing to put in your Box of Anxiety.  Honestly, at the moment I'm more concerned about what Donald "Cheeto Benito" Trump and his cronies could potentially do to the United States on the way out the door.  In my experience, assholes can do more damage than ash holes.

Even the super-sized ones.

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One of the most compellingly weird objects in the universe is the black hole -- a stellar remnant so dense that it warps space into a closed surface.  Once the edge of that sphere -- the event horizon -- is passed, there's no getting out.  Even light can't escape, which is where they get their name.

Black holes have been a staple of science fiction for years, not only for their potential to destroy whatever comes near them, but because their effects on space-time result in a relativistic slowdown of time (depicted brilliantly in the movie Interstellar).  In this week's Skeptophilia book-of-the-week, The Black Hole Survival Guide, astrophysicist Janna Levin describes for us what it would be like to have a close encounter with one of these things -- using the latest knowledge from science to explain in layperson's terms the experience of an unfortunate astronaut who strayed too close.

It's a fascinating, and often mind-blowing, topic, handled deftly by Levin, where the science itself is so strange that it seems as if it must be fiction.  But no, these things are real, and common; there's a huge one at the center of our own galaxy, and an unknown number of them elsewhere in the Milky Way.  Levin's book will give you a good picture of one of the scariest naturally-occurring objects -- all from the safety of your own home.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]