When Mount St. Helens erupted in the State of Washington on May 18, 1980, it became the deadliest and most economically destructive volcanic eruption in the history of the contiguous United States. The devastating results were not only measured by the fatalities and massive destruction but it also left behind about 540,000,000 tons of ash over an area of more than 22,000 square miles. The enormous task of cleanup was daunting. This is where serendipity stepped in to create great beauty from the ashes.Â
During the salvage effort, workers from a regional timber company were using acetylene torches to cut through twisted metal debris and they accidentally discovered that the torch melted the volcanic ash into a green glassy substance. This led to laboratory experiments that determined green glass could be produced by heating the ash to 2700° Fahrenheit and then rapidly cooling it. The glass quickly began being commercially produced and faceted into gemstones. It is marketed under the names Obsidianite, Helenite, Emerald Obsidianite or Mount St. Helens Obsidian. Its stunning green color has made it an attractive alternative to the more expensive emerald gemstone, though not as durable (a hardness of 5 to 5 ½ as compared to 7 ½ to 8 for emerald). Blue and red varieties are also produced by adding coloring agents to the melt.
The Section of Minerals obtained a faceted stone of Obsidianite as part of a donation of gemstones in 2009. It is a green oval cut stone, as you can see from the photo, and weighs 42.1 carats. Future plans are to incorporate this stone in the Treated and Synthetic Gemstones exhibit case in Wertz Gallery.
Debra Wilson is the Collection Manager for the Section of Minerals at Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.
Magma chambers are pockets of molten rock that are close to the surface of the earth’s crust. These “hot spots” rise to the surface and create pressure. The hot spots can be caused by subduction (two plates colliding) or rift valleys (two plates pulling apart). Usually, thick plugs of solid rock many millions of tons keep the magma down, but pressure builds up and eventually the mountain erupts. The eruption usually spews magma out of a central vent until the pressure is relieved and the magma chamber is emptied, until it fills again.
Karymsky Lake is a crater lake located in the Karymsky volcano in Russia. With a radius of 5 km it was once one of the world’s largest fresh water lakes, but as a result of a recent eruption toxic gases turned this into one of the largest acid water lakes.
On this day in 1985, the Nevado del Ruiz volcano near Armero, Colombia erupted. The eruption caused lahars to occur, causing the deaths of nearly 25 000 people. If you’re unfamiliar with the term lahar, the brief rundown is they are essentially volcanic mudflows. In this instance the eruption melted the ice caps on the mountain causing the massive lahars to travel through a combined 14 villages at a rate of six meters per second, destroying utterly everything in their path. It was during this event that 13 year old Omayra Sanchez was trapped up to her neck in concrete, mud and debris. When rescuers found her they discovered that her legs were trapped and she could not be extracted from her pit. Omayra spent the remaining 60 hours of her life trapped waiting for pumps to arrive so that a rescue attempt could occur. During the course of the rescue efforts, photographer Frank Fournier took the photograph above, ultimately winning the World Press Photo award for the year 1986. The photograph has since gone on to become renowned for Omayra’s haunting expression and her state of despair, and is considered one of the most moving pictures taken. Omayra Sanchez died on November 16, 1985.
A fissure vent, also known as fissure eruptions or volcanic fissures, are linear volcanic vents which erupt in awesome curtains of fire. They are most common with the low, sloping shield-type volcanoes that occupy rift zones. Iceland, Hawaii, and East Africa are hosts to many famous fissure volcanoes.Â
Fissure eruptions produce flood basalts that can eventually produce spatter cones which line the vent. This gives the illusion that it is multiple volcanoes erupting at once, when it is simply a volcanic dike connected to a magma chamber feeding into a system of lava tubes.
Yellowstone erupts like clockwork with a periodicity of approximately 600,000 years – in case you were curious, it last erupted 630,000 years ago. The initial blast would probably instantly kill everyone and everything from about Salt Lake City, Utah to Billings, Montana and Salmon, Idaho to Casper, Wyoming (the purple), though everything between San Francisco and Chicago would basically be unlivable due to ash fall, and ash would rain as far away as Mexico and southern Florida.
The ash would be pretty devastating for the United States The fallout would include short-term destruction of Midwest agriculture, and rivers and streams would be clogged by gray muck. On top of that, global cooling would wreak havoc on global agriculture for more than a decade likely spawning famine and severe winters.
ANCIENT HISTORY MEME – 1/10 Events in the Ancient World
“Ashes were already falling, not as yet very thickly. I looked round: a dense black cloud was coming up behind us, spreading over the earth like a flood.’Let us leave the road while we can still see,’I said,’or we shall be knocked down and trampled underfoot in the dark by the crowd behind.’We had scarcely sat down to rest when darkness fell, not the dark of a moonless or cloudy night, but as if the lamp had been put out in a closed room.”
      ~ Pliny the Younger, eye-witness account of the Destruction of            Pompeii addressed in a letter to Tacitus.
🔥 There is beauty in destruction🔥 