(Fig. 2.18) Plinian Eruption.
Plinian eruptions are probably the most explosive and powerful of all. They often start suddenly and unexpectedly after a long quiet period.
Plinian eruptions occur when utmost viscous magma containing a lot of gas explodes in the depth of the volcano by which the crater pipe functions as the barrel of a shotgun. An enormous gas escape shoots upwards with a very high speed whereby an enormous ash cloud comes into existence.
Ashfalls, ashflows and pyroclastic flows (nuées ardentes) predominate. Lava flows may be emitted when the eruption ends.
Plinian eruptions can blow volcanic material very high into the atmosphere which may result
in climate changes. This occurred during the eruption of Pinatubo.
As the eruption ends, the whole summit area may collapse forming a caldera. Plinian eruptions are named after Pliny the Elder and Pliny the Younger. They gave us a clear view on the classic eruption of Vesuvius in AD79.