Apocalypse Chile: Lightning from Mt. Doom?
Ominous rumblings accompany the startling images of lightning surrounding the erupting volcano, Mt. Chaiten in Chile. On the scale of volcanoes, Mt. Chaiten is building from a Plinian toward an Ultra-Plinian magnitude eruption.
I have been watching the eruption of Mt Chaitén in Chile, South America very closely for the last few weeks. It appears as if it may produce a major eruption soon. The last known eruption was in 7420 BC ± 75. The progress of the 2008 eruption has been as follows.Chaiten began quite small, and has been building since. Seismic activity suggests the potential for much larger eruptions to come. Stay tuned.
April 30: A significant earthquake preceded the first explosions;
May 2: More earthquakes arrayed radially around the caldera implying a very large magma chamber;
May 15: Near steady-state explosive eruptions (Plinian) releasing about two cubic kilometers of ejecta of 4-5km in altitude.
Eruptions are rated by the Volcanic Explosivity Index (VEI). The following are examples of recent eruptions and their VEI.
VEI=5 Plinian, ejecta > 1 km³, e.g. St. Helens (1980)
VEI=6 Plinian/Ultra-Plinian, ejects > 10 km³, e.g. Mount Pinatubo (1991)
VEI=7 Plinian/Ultra-Plinian, ejecta > 100 km³, e.g. Tambora (1815)
VEI=8 Ultra-Plinian, ejecta > 1,000 km³, e.g. Toba (73,000 BP) __NicheModeling
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