Volcanoes (pt. 1)

Mar 19

We’ve all see movies of volcanic eruptions. The terror! The error! There’s a lot of science that goes into volcanoes and frankly, people tune out when fancy terms start showing up in a conversation. But, you’re here because you want to know more.

I planned to have a much cooler post with sketches and charts but at the moment I am crunched for time on all fronts right now. I settled for explaining basic terminology, giving a list of things specific to eruptions or cones, and linking my heart out to all the amazing sites that explain things so much better than I can under time-constraints.

Easy-read information on how volcanoes work, glossaries of terminology, and pictures.

What is a volcano?: https://volcanoes.usgs.gov/vhp/about_volcanoes.html

Glossary of terms: https://volcanoes.usgs.gov/vsc/glossary/

FAQs: https://volcanoes.usgs.gov/vsc/file_mngr/file-153/FAQs.pdf

Volcanoes: http://volcano.oregonstate.edu/volcanoes-lesson-5

Volcanic Terms: http://volcano.oregonstate.edu/volcanic-terms-lesson-6

Volcanic cones: http://volcano.oregonstate.edu/volcanic-cones-and-eruptions-lesson-8

Lava Flows and Pyroclasts: http://volcano.oregonstate.edu/lava-flows-and-pyroclasts-lesson-7

Exploring: Volcanic Activity: https://www.usgs.gov/science-explorer-results?es=volcanic+activity

Overview of types:

https://geology.com/volcanoes/types-of-volcanic-eruptions/

Pick a volcano and search the Internet with the scientific terms to get exactly the type of information you’re looking for.

Shield cones form from hot, runny lava that is erupted from the volcano through its summit and the many side vents and fissures throughout the volcano’s flanks. Shield cones are low, very broad, and gently sloping. (SEE: Mauna Kea [Hawaii])

Cinder cones get their name from the material that forms them, cinders. Cinder cones are the simplest volcanic formation. They form from explosions of red, hot magma cinders and ash. These cinders and ash settle around the main vent and build a steep sided cone. Very little lava is erupted from a cinder cone. Cinder cones very rarely rise to more than 1,000 feet above the surrounding landscape. Cinder cones are known for their very violent, explosive, exciting eruptions.

Stratovolcanoes or composite cones are formed from a combination of eruptions. First the volcano will have an explosive eruption that ejects huge amounts of steam, gas and ash. This will be followed by the ejection of lava. A large stratovolcano will be built with many layers of ash and lava. Stratovolcanoes are the most common type of volcanic cone. There are many famous stratovolcanoes in the world. Mt. St. Helens and Rainier in Washington, Mt. Fuji in Japan, Mt. Pinatubo in the Philippines, and Mt. Etna in Sicily are all examples of stratovolcanoes.

Quoted from Lesson 8: http://volcano.oregonstate.edu/volcanic-cones-and-eruptions-lesson-8

Icelandic, or, fissure eruptions

Large amounts of very hot, thin, runny, fast flowing lava, fire fountains [This type of lava flows the fastest but still slow (9-12 feet per day) and is easily outrunable.]
Surfaces through long cracks (fissures) that can sometimes reach 15 miles long
Cone Shape: Shield - low and broad, erupt many times over same area, creates thick, large lava plateaus

Examples for Research

Krafla Volcano (Iceland)

https://www.wired.com/2015/12/peter-holliday-where-the-land-rises/

https://en.wikipedia.org/wiki/Fissure_vent

http://www.geology.sdsu.edu/how_volcanoes_work/Fissure.html

Hawaiian

Many fissures, fire fountains, hot, thin, runny, fast flowing lava
Cone Shape: Shield
Most lava comes from main vent at summit, not fissures, building steeper cone

Examples for Research

Mauna Kea, Hawaii

Strombolian

Short lived eruptions that shoot think, pasty lava into the air, also bursts of steam and gas. Red hot magma cinders and ash
Little or no lava
Cone Shape: Cinder
Steep sided cone built up in layers
Very rarely rise more than 1,000 above the surrounding landscape
Violent, explosive, exciting eruptions

Examples for Research

Paricutin, Mexico

Mt Vesuvius, Italy

https://en.wikipedia.org/wiki/Strombolian_eruption

http://www.geology.sdsu.edu/how_volcanoes_work/Strombolian.html

https://www.volcanodiscovery.com/photoglossary/strombolian-eruption.html

Vulcanian