Another Popocatépetl gallery – probable dome explosion tonight

Some Tlamacas webcam captures during the most significant light show I’ve seen there in the few years since I’ve been watching. Most likely, a big dome up there blew up. It’s back to the usual lower level of incandescence now. No change in the alert level.

We may find out more details with tomorrow’s CENAPRED update. (New: See update note below images.)

April 20th: Here is the CENAPRED English bulletin for today. Below that are two images from the bulletin: a closeup of the crater from the overflight, as well as an image of last night’s explosion from another angle.

April 20 11:00 h (April 20, 16:00 GMT)

In the last 24 hours, the monitoring system at Popocatépetl volcano registered 24 low to moderate exhalations, accompanied by emissions of water vapor, gas and sometimes ash. Yesterday, at 23:23h (local) an explosion occurred at the crater throwing incandescent fragments reaching around 900m on volcano slopes. A dense ash column reached 2 km. After the explosive event, the overall activity returned to its previous level.

Also recorded segments of low amplitude tremors, accumulating about 20 minutes.

At the time of this report the volcano can be seen with a continuous plume of water vapor and gases.

On april 16th, with support from Secretaría de Marina a flight was made over the crater, in which the dome could be seen and photographed.

The Volcanic Alert Level remains at Yellow Phase 2.

The expected activity scenarios in the next hours, days or weeks are: moderate exhalations, some with ash emissions; occasionally mild incandescence during nights and sporadic low level explosions with low probabilities of incandescent fragments at short distances from the crater.

CENAPRED places particular emphasis in the following recommendations:

1. Access is restricted in a radius of 12 km from the crater. For this reason the permanence in this area is not allowed.

2. The road between Santiago Xalitzintla (Puebla) and San Pedro Nexapa (Mexico State), including Paso de Cortes, is open only to controlled traffic.

3. To the authorities of Civil Protection, to maintain preventive procedures, according to operative plans.

4. To the population, to be aware of the official information emmited.

Popocatepetl Volcano is monitored continuously 24 hours a day.

This is what exploded last night – the “smoking” area on this April 16th image, taken about three days before the event. (Click image to view the full size at CENAPRED’s site. It’s glorious!)

CENAPRED (April 16, 2013, overflight)

CENAPRED (April 16, 2013, overflight)

Fire and ice

Popo has a very strange-looking lava dome, as compared to, say, Mount St. Helens in Washington State or Redoubt in Alaska.

Someone knowledgeable at Eruptions blog once noted that’s probably because Don Goyo’s domes explode so often (that’s where those usually small-scale ash puffs/exhalations/vulcanian events up there come from – last night’s was especially big).

Here’s why Mount St. Helens’ lava (and that of Popocatépetl and Redoubt) goes up and out instead of flowing like Hawaiian lava.

Of note, see the “scale” thingies on the outside of the crater rim in the lower right corner of this image? Those are glaciers, I believe. Huge, huge glaciers.

Glaciers have been found on three volcanoes in Mexico, the other two being Pico de Orizaba (Citlaltépetl) and Iztaccíhuatl.

I have seen them called tropical glaciers but apparently they aren’t, technically, because Mexico is outside the Intertropical Convergence Zone. So let’s just call these ice fields on Mexico’s three highest mountains “the only mountain glaciers in tropical North America.”

Another view of last night’s dome explosion

Here is what the explosion looked like from the Altzomoni cam:

CENAPRED

CENAPRED

Yeah – that’s one reason why they have an exclusion zone around the volcano.



Categories: volcanoes

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