The video I found is of Mount Tavurvur erupting in 2014. The eruption captured in this video is an explosive one. The lava is not just flowing out, there is some pressure built up which leads to the explosion. The video also captures the sound burst which I thought was very cool.
Mount Tavurvur is an active volcano in Papua New Guinea and is considered to be quite dangerous. It is a cinder cone. I think it is fairly new, but I am unsure and couldn't find the age of it. Cinder cones are built from ejected lava fragments that begin to harden in flight. It is relatively small at a height of 223 meters, with steep sides and a characteristic crater. (Map from http://www.dailymail.co.uk/sciencetech/article-2747577/Holy-smokes-Watch-explosive-moment-volcano-erupts-triggers-SONIC-BOOM-sending-shockwaves-sky.html)
from https://www.washingtonpost.com/news/capital-weather-gang/wp/2014/09/03/ nasa-satellite-captures-incredible-extent-of-tavurvur-volcano-ashfall/
Tavurvur is a sub-vent of the Rabaul caldera and is the most active volcano in that caldera. The caldera Rabaul violently exploded in 1994 and destroyed the island's largest city and since then Mount Tavurvur is showing the most activity in that caldera.This graphic is from NASA and shows the ashfall from the most recent eruption of Tavurvur, pictured to the left. While we don't have anything quite that exciting happening locally, we do have two volcanic tuff cones nearby, the Menan Buttes, pictured below. These were formed about 10,000 years ago when magma ran into an aquifer and the hot magma was explosively fragmented. Overall, volcanos are awesome! No matter if the explosion is effusive or explosive, it is definitely a powerful thing to see, even if it's just through video.
from http://trailrunner.com/event/spitfire-ultra-trail-challenge-at-menan-butte/
One day, as I was walking home from work, I decided to take the long, scenic route home. There was not a lot to see as I walked so I let my mind wander. I absentmindedly began thinking about the article I had just read on karst topography and how, in places such as Southern China, Puerto Rico, and Cuba, the karst development is so advanced that there are tall, immense, tower karsts just dotting the landscape, formed by the slow, but powerful groundwater eroding the limestone in that area. "Nothing interesting like that around here," I mumbled to myself. Famous last words. At that moment, I knew that something wasn't quite right and before I could do anything I found myself a good 20 feet lower than I had previously been. The ground I walked on had literally just broken beneath my careless feet. As I slowly moved my body around to make sure nothing was hurt or missing, I looked around me. I seemed to have landed in a cavern , an underground chamber. I wondered how...
I went and walked around for a couple hours around Rexburg and couldn't really identify any minerals, so I decided to go back to my roots.I'm from a little town called Dubois. Not too far north is an opal mine in Spencer, Idaho. Opal is a silicate mineral and can form in all rock environments, especially in igneous environments. It is a precious gemstone and can be quite expensive to buy. It can be identified by it's luster, streak, and darkening in heat. Here are some facts about opal: Chemical composition: S iO 2 · n H 2 O. Color: c olorless, white, yellow, red, orange, green, brown, black, blue, pink Streak: white Luster: subvitreous to waxy Hardness: 5.5-6 Specific Gravity: 2.15 Fracture: conchoidal to uneven Cleavage: none Diagnostic Feature: darkens upon heating The cool thing about this opal mine is that the public can go mine for just $15. You can stay as long as you like and can bring out a pound of rocks. I've seen some pretty cool opa...
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