GG231 Lecture Notes - Lecture 3: Mount St. Helens, Pyroclastic Flow, Basalt
Document Summary
It is the extent, speed, composition and volume of material that determines the level of hazard of the event: volcano types, stratovolcano or composite volcano. Location: alaska, washington, oregon, british columbia, pacific rim. Eruption and hazard: erupt less frequently, but when they do they are explosive: shield volcano. Shape: gentle arch or dome with gentle slopes. Location: common on the hawaiian islands, iceland, and some islands in the indian ocean. Eruption and hazard: generally, have nonexplosive eruptions of very hot, low viscosity, basaltic magmas: volcanic domes. Shape: steep sided mounds of lava that form around vents from the eruption of highly viscous, silica-rich magmas: cinder cones. Shape: relatively small volcanoes made of nut-fist-size pieces of red or black basalt. The cones are round to oval in surface form and commonly have a crater at their top. The natural service functions of volcanoes can benefit humans as well as the natural environment: volcanic soils.
