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Old 07-18-2015, 05:27 PM
kydave kydave is offline
Join Date: Apr 2007
Location: A Louisville transplant in Silicon Valley
Posts: 12,501

VEI – 8 eruptions are colossal events that throw out at least 1,000 km3 (240 cu mi) Dense Rock Equivalent (DRE) of ejecta.

VEI – 7 events eject at least 100 cubic kilometres (24 cu mi) DRE.

VEI – 7 or 8 eruptions are so powerful that they often form circular calderas rather than cones because the downward withdrawal of magma causes the overlying mass to collapse and fill the void magma chamber beneath.

By way of comparison, the 1980 Mount St. Helens eruption was a VEI-5 with 1.2 km3 of ejecta.

There was a 5.1 quake right before the eruption. That's not much as earthquakes go.

Last edited by kydave; 07-18-2015 at 06:04 PM.
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