logging in or signing up Volcanoes Noormahl Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 391 Category: Others/ Misc License: All Rights Reserved Like it (3) Dislike it (0) Added: June 21, 2007 This Presentation is Public Favorites: 0 Presentation Description No description available Comments Posting comment... Premium member Presentation Transcript Volcanoes : Volcanoes Volcanoes: Volcanoes Evidence that we live in an active planet The gods of the underworld Millions of people live near active volcanoes The greatest geological hazardMount Saint Helens- after: Mount Saint Helens- after Hazard: HazardFuture hazard: Future hazard Population near big, recently active volcanoes Seattle Mexico City Quito Indonesia Japan Lava: Lava Molten rock that flows on the surface Basaltic Lava low silica, fluid, low gas, not explosive Andesitic Lava high silica viscous gas-rich explosive Types of volcanoes: Types of volcanoes 1. Shield Volcanoes Hawaii, Iceland Basaltic 2. Stratovolcanoes (or composite) Mt. Saint Helens, Pinatubo, etc Andesitic ExplosiveShield Volcanoes: Shield Volcanoes Huge broad cones Gentle slopes Made from lava flows Basaltic Form at hotspots Not very dangerous PredictableStratovolcanoes(composite): Stratovolcanoes (composite) Andesitic lava Rich in dissolved gases Violent eruptions alternate with lava flows Steep-sided cones Very dangerous UnpredictablePyroclastic Flows: Pyroclastic Flows Product of explosive eruptions Hot ash shot up into the atmosphere Ash column collapses Pyroclastic flow can travel 60 mi/hr Ash can fall 100’s of miles away Ash may affect global climateMt. Saint Helens before: Mt. Saint Helens before Phreatic (vapor) eruption: Phreatic (vapor) eruption Bulge: Bulge Mt. St. HelensPyroclasticEruption: Mt. St. Helens Pyroclastic EruptionAfter the eruption: After the eruption Lahars (mudflows): Lahars (mudflows) Lahars (mudflows): Lahars (mudflows) Very destructive Kill as many people as the eruption itself Loose ash forms mud avalanches Glaciers on top of volcano melt Rain Inside a volcanoe: Inside a volcanoeSlide37: Pyroclastic eruptionVolcanic landscape: A Caldera (Crater Lake): Volcanic landscape: A Caldera (Crater Lake) Crater lake formation(caldera): Crater lake formation (caldera) 1. Early eruptions from composite cone 2. Great eruption empties the magma chamber 3. Summit collapses 4. Caldera fills with waterSlide44: Plate Tectonic Settings of VolcanismSlide45: Plate tectonic settings of volcanoes You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
Volcanoes Noormahl Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 391 Category: Others/ Misc License: All Rights Reserved Like it (3) Dislike it (0) Added: June 21, 2007 This Presentation is Public Favorites: 0 Presentation Description No description available Comments Posting comment... Premium member Presentation Transcript Volcanoes : Volcanoes Volcanoes: Volcanoes Evidence that we live in an active planet The gods of the underworld Millions of people live near active volcanoes The greatest geological hazardMount Saint Helens- after: Mount Saint Helens- after Hazard: HazardFuture hazard: Future hazard Population near big, recently active volcanoes Seattle Mexico City Quito Indonesia Japan Lava: Lava Molten rock that flows on the surface Basaltic Lava low silica, fluid, low gas, not explosive Andesitic Lava high silica viscous gas-rich explosive Types of volcanoes: Types of volcanoes 1. Shield Volcanoes Hawaii, Iceland Basaltic 2. Stratovolcanoes (or composite) Mt. Saint Helens, Pinatubo, etc Andesitic ExplosiveShield Volcanoes: Shield Volcanoes Huge broad cones Gentle slopes Made from lava flows Basaltic Form at hotspots Not very dangerous PredictableStratovolcanoes(composite): Stratovolcanoes (composite) Andesitic lava Rich in dissolved gases Violent eruptions alternate with lava flows Steep-sided cones Very dangerous UnpredictablePyroclastic Flows: Pyroclastic Flows Product of explosive eruptions Hot ash shot up into the atmosphere Ash column collapses Pyroclastic flow can travel 60 mi/hr Ash can fall 100’s of miles away Ash may affect global climateMt. Saint Helens before: Mt. Saint Helens before Phreatic (vapor) eruption: Phreatic (vapor) eruption Bulge: Bulge Mt. St. HelensPyroclasticEruption: Mt. St. Helens Pyroclastic EruptionAfter the eruption: After the eruption Lahars (mudflows): Lahars (mudflows) Lahars (mudflows): Lahars (mudflows) Very destructive Kill as many people as the eruption itself Loose ash forms mud avalanches Glaciers on top of volcano melt Rain Inside a volcanoe: Inside a volcanoeSlide37: Pyroclastic eruptionVolcanic landscape: A Caldera (Crater Lake): Volcanic landscape: A Caldera (Crater Lake) Crater lake formation(caldera): Crater lake formation (caldera) 1. Early eruptions from composite cone 2. Great eruption empties the magma chamber 3. Summit collapses 4. Caldera fills with waterSlide44: Plate Tectonic Settings of VolcanismSlide45: Plate tectonic settings of volcanoes