You can still find news stories about Popocatépetl’s “shock-wave” explosion on June 17. A quick check this morning showed the most recent one was dated June 22.
That was a breathtaking explosion, and we were lucky – it was caught on camera. Of course, everybody is going to talk about it for days.
Sensationalism draws readers, and volcanoes sometimes can be spectacular, so writers will always play up the dramatic.
I’m guilty of that, too (though the Cracked editors wrote most of that article, it leaves me open to charges of prostituting my knowledge; however, I’m a writer, not a scientist, and struggling to find ways to use what little knowledge I have – humor, it turns out, is likely not the way to go).
Here’s the thing, though. The exciting stuff skews our perception of volcanoes and the hazards they actually represent.
That matters, even if you don’t live near a volcano. These “fire mountains” can be very powerful once they get going, enough so to interfere with your life at a distance.
Much of the time, though, they will just have a one-off shot, or else have a much lower-level baseline activity (as is the case so far at Popocatépetl).
It’s difficult for scientists, let alone the general public – who must get their information filtered through journalists – to get a good feel for what to expect from any given volcano.
To see how this works, let’s take a closer look at Popo and another volcano you might have heard of, though, like me, you may not be able to correctly pronounce its name: Eyjafjallajökull, in Iceland.
I will include Eyjaf links from Dr. Erik Klemetti’s Eruptions blog in 2010 – it was hosted at Science Blogs at the time, not at its current location at Wired. That was how I learned of the eruption and watched it online, and many of the reader comments are extremely helpful.
Dr. K’s posts on the volcano start here. To follow the posts along forward in time, click the “Previous” button near the bottom of each page of collected posts.
This volcano represents the one-off shot. It had a dramatic eruption and then stopped in just a couple months.
Early in March 2010 there were signs of activity at Eyjafjallajökull, which had last erupted in 1823. Scientists and knowledgeable amateurs knew it was coming, and waited eagerly.
Finally, on March 20, Eyjaf erupted.
First it formed a fissure about 1 km long and erupted in fountains and red lava flows, like a Hawaiian volcano. That combination of hot fire against ice and snow drew tourists to Iceland from all over the world.
That’s the “wonder” reaction people can have with a volcanic eruption.
Then, on April 14, Eyjaf got mean. The fissure closed, but the magma still was rising and it found a new path, under a nearby glacier. The meeting of vast quantities of hot lava and ice was explosive.
People didn’t have to travel to Iceland any more – the volcano was coming to them. And soon people couldn’t travel through the region much at all because of concerns about ash damaging jet engines.
Eyjaf eventually settled down in May, and by June a crater lake had formed there.
However, at the height of the explosive phase European airlines lobbied EU officials, unsuccessfully, to reopen air space. News headlines at that time sometimes made the correct decision to close air space for six days look wrong.
Today most people remember the travel difficulties. Fortunately, no one has to hold memorial services – nobody died in the eruption, though some domestic animals did. The economic cost, however, was very high.
After Eyjafjallajökull started to calm down, there were scary news stories about the possibility of Hekla or Katla erupting. These were based in the reality that Eyjaf’s eruption was not an extreme one, by Iceland standards, and that eventually (no one knows when) there will be an even bigger one there. There were few objective signs then that either Hekla or Katla was about to let go, but the stories got hits/sold copies.
Interestingly, when there was some seismic activity at Katla in the fall of 2011, it didn’t even make the news cycle.
You can’t, therefore, simply go by what is reported in the news. It’s difficult, however, to find an information source in the middle – well resourced, but not too scientific or too “eyeballs” oriented.
I hope to fill that gap, someday, but there is still a ways to go.
This volcano is in it for the long term, but it’s erupting in such a way just now that there really isn’t much left on the geological record.
According to Mexico’s National Center for the Prevention of Disasters (CENAPRED, in Spanish), the Colossus of Puebla began its current round of activity in December 1994 after seventy years of inactivity (source – Spanish, PDF). Its eruptive style is either vulcanian or strombolian – I’m not sure which.
Basically, it steams most of the time (in fact, it is well known for its pressure-balancing hydrothermal/outgassing system) and sometimes also puffs out large boluses of sulfur dioxide as well as small to moderate amounts of ash. There can be explosions, because Popocatépetl has a sticky lava that tends to move up and form domes, rather than flow out prettily across the landscape as Eyjaf did early in 2010. These lava domes get bigger and bigger, and then they explode, sending up large ash columns and throwing fragments out of the crater over 3 km. There can also be pyroclastic flows and lahars.
From the geologic record scientists know, per CENAPRED, that the volcano that we today call Popocatépetl has been active for half a million years. There have been at least three other volcanic edifices – Nexpayantla, Ventorrillo and El Fraile – in the same general area where Popo now sits.
Those others were destroyed by what CENAPRED calls “extraordinarily large eruptions.” Someday, Popo will go that route, too. It now sits in the midst of 25 million people, and that population will probably grow with the passage of time.
There’s a mind trick scientists and interested amateurs can do when confronting a monumental potential disaster like that – I suppose one would call it “trying to understand the situation.” It’s not something you put in headlines, this understanding that such a catastrophe could happen in the next moment, but that most likely it won’t.
I think the Mexican authorities, however, have done an excellent job of putting it into words with their “Plan Popocatépetl” (Spanish, PDF). That’s disaster planning that everybody else in the world can learn from.
Not surprisingly, Popo is monitored very closely, and this is where we get back to reading the news again.
The Internet is still chattering about Popocatépetl’s big blast on June 17. The drama of that video got everybody thinking about an eruption, but CENAPRED had to decide if it justified raising their alert level, which is currently Yellow, phase 2 (Spanish, PDF).
The scientists have cooler heads than the rest of us. They have to be cool – how else could they cope with a volcano that does this sort of thing all the time?
The volcanologists at CENAPRED have multiple cameras, GPS stations, seismographs, etc, set up all around the volcano. One of the seismographs is online and open to the public as a webicorder.
This allows them to “see” the volcano even when its summit is shrouded in clouds. Authorities have also established a 12-km safety zone around the crater and restricted travel in some vulnerable passes.
There was no sign of a major event upcoming, either on the 17th when the shockwave happened or today, when that “puffing” occurred. CENAPRED didn’t raise the alert level.
So, when you read that “a Mexican volcano” is about to “blow its top,” take the news with a grain of salt. Even better, check with CENAPRED.
You can do this with any volcano. Track down reliable sources and follow them daily or at least weekly, so you can know what’s really going on.
I happen to be enchanted with Popocatépetl, but there are many volcanoes in the world. More and more of them can be viewed on webcams. Look around – you might be surprised by all the active geology you can see, right here on your own screen.