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Crystal Clocks: How minerals in magmas can be used to unravel what happens before an eruption (Guest Blog by Dawn Ruth)

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- Guest blogger Dawn C.S. Ruth @rockdoc11 Keeping time with volcanoes Hi everyone. I’m neither Alison nor Janine. My name is Dawn C.S. Ruth and, like our fearless leaders, I also study volcanoes. However, where Alison uses experiments to delve deeper into volcanic processes, and Janine uses satellites to spy on volcanoes, I look at the minerals to see how magma moves and behaves before an eruption.

The trees of Calbuco

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-Alison Most of my research can be described as looking at rocks to figure out what happened in the past.  There are many deposits from volcanic eruptions that don't just contain rocks. As volcanic soils are very fertile, many volcanoes are forested which means that falling ash or debris flows interact with trees and other plants. The way trees are damaged by the eruption can tell us a lot about what happened. The trees in the blast zone of Mount St. Helens are a dramatic example. Trees blown down by the 1980 later blast at Mt St Helens (image from 2015). I was recently lucky enough to visit Calbuco Volcano in the lake region of Chile. You may remember the impressive pictures of Calbuco erupting at sunset on April 22, 2015.  This heavily forested stratovolcano produced a large plume (which dropped tephra, coarse scoria on the slopes of the volcano and ash all over eastern Chile and Argentina), pyroclastic flows, and lahars (debris flows) from melting gla...