Tag Archives: Mexican volcanoes

Jun 17 2018

Popocatepétl: A Dangerous Volcano

People in central Mexico have always felt a strong personal link with Popocatepétl, which they often call Don Goyo.

As we saw last time, when this volcano broke its five-decade silence with a VEI-2 bang in 1994, local people responded with traditional ceremonies; artists were drawn to the event; government officials took emergency measures; and scientists expanded their monitoring networks.

For almost a quarter of a century now, Don Goyo has been on center stage. People have adjusted to it and are moving on with their lives, as people always do after a natural disaster.

But scientists just updated the official hazard map (Spanish) for Popocatépetl, which we’re going to take a look at in this post.

The volcanologists did reassure everybody that there is no sign of any increased or upcoming increase in activity; the volcano is still at a “Yellow, Phase 2” alert level.

Also, to counter popular rumors, they stated in no uncertain terms that Don Goyo is not connected to Guatemala’s Fuego, which recently had a deadly eruption, or to Kilauea, out in Hawaii, with its spectacular lava flows. Each of these three volcanoes has its own plumbing system and exists for different geological reasons.

The problem with Popocatépetl is that, not only in 1994 but also at any point in modern times, this volcano has never shown the levels of violence that the geologic record proves that it is capable of.

And now Don Goyo has 25 million human neighbors, unfamiliar with its historic power and living less than 65 miles (100 km) away from its summit.

Ashfall risk from Popocatépetl

Ashfall risk for Popo

See CENAPRED’s hazard map (Spanish) for details. “Ciudad de México” is Mexico City.

  • The dotted line shows the area that would get at least 4 inches (10 cm) of ash if Don Goyo had another eruption as powerful as one about 14,000 years ago.
  • Red: In a big eruption, this unfortunate area could get lots of volcanic ash (up to yards/meters in depth) as well as a bombardment of rocks up to a foot (30 cm) in size.
  • Orange: Just a little ash would fall here in a small eruption, but up to 3 feet (1 meter) or more in a big one.
  • Yellow: This region isn’t at much risk of ashfall in small eruptions at Popocatepétl, but it could get several inches (dozens of centimeters) in a large eruption.

Seismic sensors, deformation monitoring, and gas/hydrothermal studies can pick up signs of such approaching events, especially the big ones.
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Jun 10 2018

Popocatépetl: Don Goyo

A certain Spanish adventurer was under a lot of pressure in the summer of 1519.

He and his men had forfeited their lives by mutinying in order to go seek their fortune in the New World. After arriving there, he had scuttled the boats to thwart an unhappy faction that wanted to turn back; and now enemies surrounded them on every side while up ahead were the Aztecs–skillful fighters who wore elaborate constumes, launched attacks with screeching skull whistles, and would carve the heart out of your living chest or kill you in some other cruel way if they won.

Also, gunpowder–the Spaniards’ only hope of staying alive in the New World, let alone conquering it–was running low.

Despite all this, Hernán Cortés had to pause and describe for posterity something wonderful he had seen:

[E]ight leagues from this city of Churultecal are two very high and very marvellous mountains . . . at the end of August they have so much snow or something else on top that, if not snow, looks like it. And out of the one that is highest comes many times, day and night, a huge column of smoke, like that from a big house, rising from the mountain up into the clouds, as straight as a vein, with so much force as it emerges that, although up in the mountains the wind [is] always very strong, it cannot twist it.
— Hernán Cortés, quoted here, translated by Google Translate and me

Popo plume and Izta Popo

Top: Screen capture from this YouTube video (Spanish). Bottom: A 2010 sunrise view from the Aztec side of the mountains; Cortes saw them from the east. The “smoking mountain’s” plume (right) is hardly visible in this shot. What is now called Cortés Pass (Paso de Cortés) connects the two mountains. (Joaquin Martínez Rosado, public domain)

While momentary awe is always welcome, Cortés still had urgent practicalities to attend to. Recognizing an active volcano when he saw one, he sent a team under the command of Captain Diego de Ordás up to the summit to collect sulfur for making more gunpowder.

Here is what the crater of that “smoking mountain”–Popocatépetl, in the ancient Nahuatl language–looked like in 2013 when its usually icy and snow-covered slopes were dark with ash after some eruptions.

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