1 / 20

Chapter 6 – VOLCANOES

Chapter 6 – VOLCANOES. Volcanoes & volcanic hazards. Volcano Vent where lava, solid rock debris, volcanic ash, & gases erupt from inside Earth onto its surface Can be explosive or non-explosive Mt. St. Helens Kilauea. Volcanoes & volcanic hazards. Lava

betha
Download Presentation

Chapter 6 – VOLCANOES

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 6 – VOLCANOES

  2. Volcanoes & volcanic hazards Volcano Vent where lava, solid rock debris, volcanic ash, & gases erupt from inside Earth onto its surface Can be explosive or non-explosive Mt. St. Helens Kilauea

  3. Volcanoes & volcanic hazards

  4. Lava Molten rock that reaches Earth’s surface Magma Molten rock, which may include fragments of rock, volcanic glass & ash, or gas Beneath Earth’s surface Volcanoes & volcanic hazards

  5. Eruptions, landforms & materials Eruption types: Hawaiian Shield volcano Broad, flat volcano with gently sloping sides Largest volcanoes Built of successive lava flows May also produce flood basalts or lava plateaus

  6. Eruptions, landforms and materials Eruption types: Strombolian More explosive than Hawaiian Create loose volcanic rock called spatter cones or cinder cones Smallest volcanoes

  7. Eruptions, landforms and materials Eruption types: Vulcanian More explosive than Strombolian Can generate clouds of ash up to 10 km Produce pyroclastic flows Hot volcanic fragments (tephra) that flow very rapidly

  8. Eruptions, landforms & materials Eruption types: Plinian Most violent eruptions; ash columns over 20 km Produce stratovolcanoes Composed of alternating layers of solidified lava & pyroclastic material Steep sided

  9. Eruptions, landforms & materials

  10. Eruptions, landforms & materials Viscosity Degree to which substance resists flow Less viscous = runny More viscous = thick Dissolved gases Up to ~10% of magma Water vapor, carbon dioxide, sulfur dioxide, etc.

  11. Eruptions, landforms & materials Volcanic materials Pyroclasts Tephra Ash Agglomerates Tuff

  12. Eruptions, landforms & materials Volcanic materials Pahoehoe flows A’a flows Lava tubes Vesicles Columnar jointing Pillow structures

  13. Eruptions, landforms and materials Other volcanic features Crater Caldera Resurgent dome

  14. Eruptions, landforms and materials Other volcanic features Thermal spring Geyser Fumarole

  15. Eruptions, landforms and materials Other volcanic features Fissure eruptions Flood basalt Lava plateau

  16. Volcanic hazards Primary effects Lava flows Pyroclastic flows Volcanic gases

  17. Volcanic hazards Secondary effects Fires Flooding Mudslides (lahars) Debris avalanche

  18. Volcanic hazards Tertiary and beneficial effects Landscape changes Climate changes; regional & global Benefits: Replenishes minerals & fertility Geothermal energy Specific mineral deposits

  19. Predicting Eruptions Establish volcano’s history Active Dormant Extinct

  20. Predicting Eruptions Monitor changes & anomalies Microseismicity Tilting or bulging Volcanic gases Changes in ground or surface water temperature

More Related