The Hawaiian Islands were formed by erupting volcanoes. So let's follow our Hawaiian theme with a volcanoes theme, beginning with a pair of Hawaiian volcano-words, for which the links give photos.
aa – lava having a rough surface [Hawaiian, 'to burn']
pahoehoe – lava with a smooth, glassy or rippled surface. [see also here]
[Hawaiian, reduplication of hoe, 'to paddle', probably from the swirls on its surface]
– Mackie Rhodes, Instructor, March, 2004
lahar – an mud-flow "avalanche" of volcanic ash and water, down the slopes of a volcano
[Javanese for lava']
– Manila Standard Today, June 22, 2006
solfatara – a volcanic area that gives off sulfurous gases and steam
[from the Italian and Latin for 'sulfur']
– Victoria Pybus, The Independent, July 11, 1998
apoplexy (adj. apoplectic) – a fit of extreme anger; rage
[also the name of a medical condition]
My ex husband was very much into geology and I picked up a lot of the vocabulary from him.
The volcanic term I always remember is nuée ardente which means "burning cloud".
The English term is Pyroclastic flow or pyroclastic cloud.
My ex used to tell me the story of a man in St. Pierre who survived the eruption of Mt Pelee in 1902 because he was in the town's jail - the thick walls of which protected him!
fumarole – a hole in a volcanic area from which hot smoke and gases escape (see link)
[Italian, from Late Latin for 'smoke hole', diminutive of 'smoke chamber']
– Richard Monastersky, Science News, June 6, 1992
magma – hot fluid or semi-fluid rock within the earth’s crust
caldera – a crater formed by volcanic explosion or by collapse of a volcanic cone.
– Cultural inspiration on Hawaii's Big Island, Sunset, July, 2004
I spend two nights at the Lake Yellowstone Hotel, … a survivor of legions of tourists, … all drawn by the pageant of wildlife atop an ancient caldera. Miles below, like a buffed ember, is a hot spot through the crust, and the caldera awaits its wakeup call from a 600,000-year nap.
– Kerrick James, Travel America, May-June, 2004
tephra – solid matter ejected into the air by an erupting volcano
[Greek tephr, ash]
– Sid Perkins, Science News, Nov. 24, 2001