GEO 1111 Lecture Notes - Lecture 7: Viscosity, Mafic, Phreatic

• School: University of Ottawa
• Department: Geology
• Course: GEO 1111
• Professor: David Schneider

Document Summary

Geo1111 - lecture 7 - volcanoes http://www. coolgeography. co. uk/a-level/aqa/year%2013/plate%20tectonics/plate%20tectonic s/hotspots. htm. One of the biggest eruptions: toba (75 000 years ago) Nature of volcanic eruptions: factors influencing the level of violence. Temperature of magma (low temperature = more viscosity. Lava/volcanic domes: bulbous mass of cooled, gas poor lava. Bombs: ejected hot lava shaped like teardrops. Eruption columns: cloud of gas and tephra that can reach 45 km high. Lateral blast: sideway build up of pressure and magma. Pyroclastic flow/surge: gas and rock that flow like an avalanche. Caused by column or dome collapse and happens in valleys. Nu e ardente: fast inflamed pyroclastic flow of hot gas. Volcanic pipes/neck: conduit that connects the magma chamber to the surface. Lava tube: cave systems that allow the lava to move. Created by effusive eruptions coming from the main vent; Created by congealed lava and loose pyroclastic materials; Created by lava that accumulates near the vent;