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10 April 2012

Volcanology Etymology

In my liberal-arts-undergraduate life, I ended up taking a few linguistics classes to fulfill the requirements for my anthropology minor. I actually had a lot of fun, especially when we started talking about the etymology of words in modern English (otherwise known as, ‘stolen from everyone else’). Working out the component parts of a word is one of my favorite tricks for learning new vocab (I also play this game when I’m trying to deal with other languages, especially ones with a Latin base. It really works!) So this weekend I started thinking about the specialized vocabulary that geologists use.


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18 June 2011

Favorite geology word: Autobrecciation (Accretionary Wedge #35)

Well, ash-flow tuff got taken pretty quickly, but I’m fairly certain no one will come up with my favorite geology term (or the particular meaning I’m going to talk about). That word is autobrecciation. I’m not talking about the autobrecciation that happens when the surface of a lava flow breaks up and gets incorporated into a lava flow, but the meaning used in several volcanology papers about rockfalls and lava dome collapses: volatile-rich, pressurized lava dome rocks fragmenting explosively in response to rapid decompression, which occurs at a critical pressure difference between the overpressurized rock and the surrounding environment (i.e., the point when the pressure overcomes the tensile strength of the rock). As you can see in the video, the rocks basically disintegrate into a lot of fine material (and probably some leftover rock chunks), which is the perfect recipe for a pyroclastic flow.


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18 June 2010

Volcano Vocab #5: Caldera

Part of my research this summer involves visiting Los Alamos to learn how to work with a computer model; in addition to one of the world’s greatest research laboratories, northern New Mexico also hosts the Valles caldera, a major volcanic center north of Albuquerque. (Pretty much everything around me is volcanic, which means that whenever I drive or bike anywhere, I’m always staring at the scenery and going “holy crap, …


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7 May 2010

Volcano Vocab #4: Lahar

As suggested by a commenter on the last Volcano Vocab post, here’s a water-and-volcano-related term for you: Lahar (“lah-haar”).  Lahar is an Indonesian word for a mudflow of volcanic material – that is, a mass movement of volcanic debris that contains some amount of water. (A dry flow of volcanic material would usually just be called a debris flow or debris avalanche.) The key thing that distinguishes a lahar from a …


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16 April 2010

Volcano Vocab #3: Tephra

Today’s volcano word is tephra, another term that’s directly related to the Eyjafjallajökull- Fimmvörduháls eruptions going on in Iceland at the moment. Tephra (“teff-rah”) refers to any fragmented material thrown from a volcanic vent during an explosive eruption. It comes in different sizes, all of which have their own names (just to make things even more difficult!) Bombs or blocks are large rocks – 64 mm and greater in diameter (cobble to boulder …


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13 April 2010

Volcano Vocab #2: Jökulhlaup

Today’s obscure volcanologically-related word is jökulhlaup (“yer-kul-hloyp”, “YO-kel-yawp” and “yo-kul-h-loip” in varying pronunciations), which is an Icelandic word for glacial outburst floods, both of water and lahars, formed when a subglacial eruption occurs. The water for these floods is formed when heat from those eruptions melts glacial ice, forming lakes that eventually become unstable enough to break through channels in the base of the glacier and flow out from underneath …


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9 April 2010

Volcano Vocab: Guyot

I don’t want to steal the thunder of any of the Skepchicks (especially Evelyn, who’s doing a fantastic job on the Geology Word of the Week feature), but I thought I’d start a bi-weekly post on obscure or specialized volcanology words. (Yes, it’s really just an easy way for me to post, since I’ve got the Glossary of Geology sitting here and all I have to do is flip a …


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