What is the distribution and prediction of volcanic activity? Flashcards
What is the volcanic explosivity index (VEI) ?
a relative measure of the explosiveness of volcanic eruptions.
What is used to determine the explosivity value?
Volume of material, eruption cloud height, and qualitative observations (using terms ranging from ‘gentle’ to ‘mega-colossal’)
What do the numbers represent?
A value of 0 is given for non-explosive eruptions, defined as less than 10,000 m3 of volcanic material ejected. and a value of 8 representing a mega-colossal explosive eruption that can eject 240 cubic miles of material and have a cloud column height of over 20km.
What is the scale?
The scale is logarithmic, with each interval on the scale representing a tenfold increase in observed ejecta criteria, similar to the Richter scale
what is a Icelandic volcano?
It has a basaltic magma and the lava flows gently from fissures.
What is a Hawaiian volcano?
It has basaltic magma and the lava flows gently from a central vent.
What is a Strombolian volcano?
It has (thicker) basaltic magma with frequent, explosive eruptions of tephra and steam. Occasional, short lava flows.
What is a Vulcanian volcano?
It has (thicker) basaltic andesitic and rhyolitic magma it has less frequent, but more violent eruptions of gasses, ash and tephra (including lapilli).
What is a Vesuvian volcano?
It has (thicker) basaltic, andesitic and rhyolitic magma. following long periods of inactivity, very violent gas explosions blast ash high into the sky.
What is a Peleean volcano?
It has andesitic and rhyolitic magma and has very violent eruptions of nuees ardentas
What is a Plinian volcano?
It has rhyolitic magma has exceptionally violent eruptions of gases, ash and pumice. and the Torrential rainstorms cause devastating lahars.
