the vei of mt. st. helens during an 1860 bc eruption was 6.
the vei of mt. st. helens during an 1860 bc eruption was 6.
what was the vei of mt. st. helens during an 1860 bc eruption?
6
bullet::::- the long valley caldera eruption in eastern california, united states, which happened over 760,000 years ago.









































bullet::::- the 4860 bc eruption forming crater lake in oregon, united states.









































bullet::::- the 1645 bc eruption of thera in the south aegean sea, greece.









































bullet::::- the 400s bc eruption of the bridge river vent in british columbia, canada.









































bullet::::- the 79 ad eruption of mount vesuvius in pompeii, italy. it was the prototypical plinian eruption.









































bullet::::- the 180 ad lake taupo eruption in new zealand.









































bullet::::- the 946 eruption of paektu mountain in china/north korea
plinian eruption
physical and chemical characteristics of volcanic ash are primarily controlled by the style of volcanic eruption. volcanoes display a range of eruption styles which are controlled by magma chemistry, crystal content, temperature and dissolved gases of the erupting magma and can be classified using the volcanic explosivity index (vei). effusive eruptions (vei 1) of basaltic composition produce <10 m of ejecta, whereas extremely explosive eruptions (vei 5+) of rhyolitic and dacitic composition can inject large quantities (10 m) of ejecta into the atmosphere. another parameter controlling the amount of ash produced is the duration of the eruption: the longer the eruption is sustained, the more ash will be produced. for example, the second phase of the 2010 eruptions of eyjafjallajökull was classified as vei 4 despite a modest 8 km high eruption column, but the eruption continued for a month, which allowed a large volume of ash to be ejected into the atmosphere.
volcanic ash