Repost: Caribbean Plate Volcanoes: The Central American Arc


Here’s an edited 2018 post about some impressive Central American volcanoes.

The Caribbean tectonic plate gets little respect. This is probably why it lashes out so violently at times in earthquakes and volcanic explosions. (Physics, geochemistry, and complex plate interactions are involved, too.)

This relatively small chunk of Earth’s lithosphere has a lot to deal with.

First, most of it is underwater, so we laypeople don’t even give it a thought.

Then North America jostles it from the north, messing up its boundaries, while South America does the same thing from the south.

That’s a lot of pressure, but also, east and west, other plates dive underneath the Caribbean plate’s edge in subduction zones and then melt upward through it to form explosive volcanic arcs, specifically, the the Lesser Antilles in the east and the land-bound Central American Volcanic Arc (CAVA) to the west.

This post is about those Central American volcanoes — well, not all of them. There are hundreds of stratovolcanoes, lava domes, and cinder cones in this group.

Let’s look at a few of the major volcanoes, breaking it down by country.

Guatemalan volcanoes

Fuego and Acatenango are just two of the 300+ vents in this small nation. (Yes, that Fuego.)

https://youtu.be/Iu_lrblhmVs

This video disappeared, so I am embedding one that, though basically an ad, also shows spectacular views of some Guatemalan volcanoes and their processes. It additionally makes you literally feel a few of the physical difficulties that volcanologists, too, must overcome, even in subtropical regions, in order to study these fire mountains.

Also, I like what he says at the very end about “this little country of Guatemala.”



Note the city lights in the background, just a few miles away from this erupting volcano.


Monitoring: INSIVUMEH. (Spanish)

Risk: High, obviously. In fact, only Indonesia has more people living near active volcanoes than Guatemala does. (Ewert and Harpel) According to one source:

The highest risk is located around the vents of Almolonga and Santa Maria, due to the very large population living within 10 km of the volcanoes and also the high VEI 6 figure for Santa Maria as designated by the Global Volcanism Program. The areas to the south and east of Fuego are also designated high risk due to the numerous hazards that combine and overlap within these areas, from hazards generated by Atitlan and Acatenango.

Biggest known eruption: That 1902 VEI 6 event at Santa Maria, in which thousands of people died, was the second largest eruption of the 20th century (the largest one, in 1912, happened in Alaska).

And then there was the VEI 7 caldera eruption at Atitlán some 85,000 years ago. Today a lake fills the caldera left by this “Los Chocoyos eruption,” and “normal”-sized eruptions at one of the three stratovolcanoes on the calderas rim are the norm.

El Salvador volcanoes

This is the country where cameras caught the start of an eruption at Chapparastique Volcano, the most active of some 20 or so El Salvadoran volcanoes. You might have seen the video:

Monitoring: SNET. (Spanish)

Risk: High.

Biggest known eruption: A few high-end VEI 6 eruptions and one VEI 7 are listed.

Also, a VEI 6 caldera eruption at Ilopango, which sits right next to the country’s capital city, happened some 1200 to 1500 years ago.



That’s not media exaggeration — the eruption was massive.

Besides devastating the Maya politically and economically, as well as socially, this “Tierra Blanca Joven eruption” may have caused climate effects and hardship elsewhere in the world, and possibly even contributed to the Justinian Plague! (Oppenheimer)

Nicaragua volcanoes

There are at least 19 volcanoes in this country, and some of them are popular tourist destinations.



Masaya (below) is world famous, but Telica, San Cristobal, and Momotombo volcanoes are also showing signs of increased activity.


Monitoring: INETER.

Risk: Per this abstract, there are a variety of risks.

They don’t mention gas, probably because that is a common (and very dangerous) volcanic hazard everywhere.

However, it’s an especially bad problem at Masaya.



Biggest eruption: Both Apoyeque and Masaya have had VEI 6 eruptions, though not any time recently; Masaya’s eruptions are usually less intense.

Costa Rica volcanoes

This country’s beautiful string of volcanoes draws a lot of tourists.

It is gorgeous.

Monitoring: OVSICORI-UNA. (Spanish)

Risk: High.

Biggest eruption: An unexpected VEI 3 eruption at Arenal in 1968 killed 87 people, per Wikipedia. Also, a few Costa Rica volcanoes, including the Barva complex, Miravalles, and Poás have VEI 6 or 7 eruptions listed in the distant past.

Panamá

Wait, Panamá has volcanoes? Yes, at least three of them.

  • El Valle de Antón is cleverly disguised as a valley, but it’s really a 56,000-year-old caldera.


    Today, tourists hike along caldera rim trails. Petroglyphs along the way show that people have known this place for thousands of years.


  • La Yeguada hosts thermal springs, but it hasn’t erupted since some time in the Pleistocene.
  • Active Barú is Panama’s highest peak and its youngest volcano.

Monitoring: The National Civil Protection System, apparently (linked site is in Spanish). They responded to what turned out to be unfounded concerns in 2015 that Barú was going to erupt. Also, this Spanish-language government page on SINAPROC is helpful.

Risk: Barú is the youngest and most recently active volcano, so most attention focuses on it.

Biggest eruption: El Valle had a VEI 4 ignimbrite eruption about 56,000 years ago, though it has been quiet ever since.


By now, you have probably forgotten the poor Caribbean plate, lying there underneath all these Central American lands.

But geoscientists continue to be fascinated by it. They respect the seismic and volcanological risks it poses for millions of people and many nations, and they also study it for its own sake to learn more about this very complex tectonic region.

Let’s close with a view of sunrise from the summit of Barú Volcano – the only place in the world where, thanks to the narrowness of the Panama Isthmus, it’s possible to see the Atlantic and the Pacific oceans at the same time.




Featured image: Central America volcanic front. CrazyKnight. CC BY-SA 3.0.



Sources:

Bachmann, R. 2001. The Caribbean plate and the question of its formation. Institute of Geology, University of Mining and Technology Freiberg Department of Tectonophysics http://www.redciencia.cu/geobiblio/paper/2001_Raik%20Bachmann_THE%20QUESTION%20OF%20ITS%20FORMATION.pdf.

Ewert, J. W., and Harpel, C. J. 2004. In harm’s way: Population and volcanic risk. Geotimes. http://www.geotimes.org/apr04/feature_VPI.html Last accessed March 18, 2018.

Giunta, G. and Orioli, S. 2011. The Caribbean Plate Evolution: Trying to Resolve a Very Complicated Tectonic Puzzle, New Frontiers in Tectonic Research – General Problems, Sedimentary Basins and Island Arcs, ed, Sharkov, E. InTech, DOI: 10.5772/18723. Available from: https://www.intechopen.com/books/new-frontiers-in-tectonic-research-general-problems-sedimentary-basins-and-island-arcs/the-caribbean-plate-evolution-trying-to-resolve-a-very-complicated-tectonic-puzzle

Oppenheimer, C. 2011. Eruptions That Shook The World. Cambridge: Cambridge University Press. Retrieved from
https://play.google.com/store/books/details?id=qW1UNwhuhnUC

USAID/OFDA LAC Newsleter. July 2016. VDAP helps strengthen volcano monitoring systems in Costa Rica and Nicaragua. https://www.usaid.gov/sites/default/files/documents/1866/lac_newsletter_july2016.pdf




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