Sabot L'ours (sabotlours) wrote,
Sabot L'ours
sabotlours

Volcano

This is the perfect opportunity for a geology lesson! We have 2 very different volcanoes blowing their tops at the same time. Why did the one in Guatemala blow its top killing 60+ people while one in Hawaii only destroys homes? The answer is silica. The more silica found in magma means the more viscous it is. The volcanoes in Guatemala are formed due to the Cocos Plate sliding under the North American and Caribbean Plates. The magma produced is high in silica so it forms very steep-sided volcanoes due to its viscosity. The viscosity also means that its easier to build up pressure which leads to catastrophic explosions as was witnessed a few days ago (and with Mt St Helens). What I found amazing was that (according to Google Maps) there was a major highway only 4 miles away from the summit! So ash and lava only had that distance down a slope that was probably several thousand feet high. Talk about a recipe for disaster! And you wonder how a dense cloud of this debris could reach speeds of hundreds of miles per hour? The lava in Hawaii, however, comes from much deeper in the earth, and has a low silica content. That's why it's able to flow so freely down to the ocean. It has gas explosions, but nowhere near the ferocity as a stratovocano. I have been totally fascinated by the series of events that have happened there over the past few months. First the main crater overflowed the inner crater like it did when we visited a few years ago. Then there was a massive earthquake which happened just about the same time that a side volcano completely collapsed. This was the volcano that had been sending lava into the sea. Soon after that the entire east rift zone sprang to life while the summit lava pool fell several hundred feet. Unfortunately people have short attention spans and the lure of "cheap" land in paradise was too much of a draw. Any geologist would say that buying land in an active rift zone would be very risky. Hundreds of people did and are now paying the price. Just in my lifetime I have heard of several communities in this area being consumed by lava. And now it continues. I just use these opportunities to wonder and marvel at the power of nature. It's the coolness factor of knowing geology.
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