Mauna Kea, Hawaii effusive Hawaii; Etna; Iceland; Erta Image: S. Marshak “Earth, Portrait of a Planet” Ale, Nyamuragira/Africa Mt. Mayon, Philippines explosive Fuji; Vesuvius; St. Helens; Pinatubo; Popocatepetl SIO15-15: Volcanoes: The Basics
Mt. Mayon, Philippines Mt. Fuji, Japan Mt. St. Helens Mt. Rainier “...anything that looks beautiful is potentially dangerous...” SIO15-15: Volcanoes: The Basics
Lecture 3: resistance of material to flow � high viscosity: lava clogs vents -> explosive volcanism � low viscosity: lava flows easily -> effusive volcanism Image: S. Marshak “Earth, Portrait of a Planet” SIO15-15: Volcanoes: The Basics
HIGHER TEMPERATURE SiO 2 MAKES LAVA DECREASES VISCOSITY MORE VISCOUS MORE VISCOUS � high-SiO 2 (Quartz) � cold LESS VISCOUS � low-SiO 2 (Olivine) � hot Image: S. Marshak “Earth, Portrait of a Planet” SiO 2 = silica SIO15-15: Volcanoes: The Basics
Image: S. Marshak “Earth, Portrait of a Planet” LAVA • surface • volcanic • extrusive MAGMA • underground • plutonic • intrusive SIO15-15: Volcanoes: The Basics
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