EOSC 114 Chapter Notes - Chapter 12: Lava Dome, Pyroclastic Flow, Pyroclastic Fall
27 Aug 2017
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Two main styles: effusive mostly produce only lava flows, explosive gas driven, often very violent eruption, much harder to predict. If the magma is low in viscosity, then the gas will evaporate very quickly. Viscosity is going to control whether the volcano erupts explosively or not, which is related to silica content and the temperature of the magma. Viscosity, temperature, silica content, and volatile content are all interrelated and determine the eruptive style. Lava flows - the outer crust cools and solidifies, while the molten interior stays quite hot. Lava dome more felsic to intermediate magma (a rock being pushed up) the lava is building up slowly (over months) Pyroclastic fall collapsing column of ash and gas (goes up to 10"s of km in the atmosphere: most dangerous, hard to predict exactly which direction they are going in the pyroclastic column. The ash can be very heavy when built up on objects.
