1 / 77

VOLCANOES

VOLCANOES. Formation. Magma is forced upward flows out of an opening in crust. Parts of a Volcano. Parts. Vents –areas from which lava flows. Crater – bowl shaped dent where vent is located. Parts. Gas- most common steam, carbon dioxide, sulfur dioxide . Lava- molten rock on surface .

linnea
Download Presentation

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. VOLCANOES

  2. Formation • Magma is forced upward flows out of an opening in crust

  3. Parts of a Volcano

  4. Parts • Vents –areas from which lava flows • Crater – bowl shaped dent where vent is located

  5. Parts Gas- most common steam, carbon dioxide, sulfur dioxide Lava- molten rock on surface Ash- VERY small rock , minerals, volcanic glass less than 2 mm

  6. Parts • Conduit - a pipe that extends from magma chamber to vent • Magma chamber – area where magma is stored until it erupts

  7. LOCATION • Divergent boundaries • Convergent boundaries • Hot spots

  8. Divergent Boundaries • Plates move apart forming rifts • Lava flows forms rifts & cools quickly by seawater • Keeps building until it rises above sea level

  9. Iceland

  10. Surtsey

  11. Convergent Boundaries • Plates move together (collide) • Oceanic slide under continental • Older oceanic under younger oceanic • Plate melts down to form magma • Then forced upward

  12. Andes Mountains Chile Ecuador

  13. Cascade Mountains Mt. Rainier Mt. St. Helens

  14. Hot Spots • Magma burns through crust • NOT near a boundary

  15. Hawaiian Shield Volcano

  16. Lava Flowing Into the Pacific

  17. Galapagos Islands-Shield Volcanoes

  18. Factors that control type of eruption • Trapped gases • Amount of gases • Composition of Magma • How much silica

  19. Factors that control type of eruption Trapped gases Composition of Magma Low silica basaltic magma quiet eruption • escape easily less pressure quiet eruption

  20. Factors that control type of eruption Trapped gases Silica rich rhyolitic magma explosive eruption Composition of Magma • Gases build up to high pressure explosive eruptions

  21. Eruption Products Pyroclasts

  22. Eruption Products • Pyroclastics (broken pieces of volcanic rock)- tephra Ash Bombs Cinders Blocks

  23. Eruption Products Pahoehoe • Lava Aa Pillow

  24. Eruption Products • Gases • Water • Carbon dioxide • Sulfur dioxide

  25. Types of Volcanoes • Shield volcano • Quiet eruptions • Basaltic magma • Fast moving lava • Very large • Broad gentle slope • Can erupt hundreds of feet into air  fountains • Kilauea

  26. Types of Volcanoes • Cinder cone volcano • Explosive eruptions • Andesitic or rhyolitic magma • Small in size • Steep sided loosely packed • Short lived • Paricutin

  27. Types of Volcanoes • Composite (Stratovolcanoes) • Explosive or quiet eruptions • Andesitic or rhyolitic magma • Can switch from quiet to explosive forming layers of tephra and lava • Steep sided • Tall • Mt. St. Helens

  28. Classification of volcanoes • Active- currently active or erupted in recorded history Kilauea

  29. Classification of volcanoes • Dormant –“resting“ not currently erupting but likely to do so Mt. Hood, Oregon

  30. Classification of volcanoes • Extinct –not erupted in recorded history and are not expected to erupt again Mount Kilimanjaro

  31. Kinds of Volcanic Eruptions • Hawaiian • Quiet • Very fluid lava • Little explosive activity

  32. Kinds of Volcanic Eruptions • Strombolian • small amounts of lava in very short bursts • impressive booming sounds, but the eruptions are relatively small • tephra

  33. Kinds of Volcanic Eruptions • Vulcanian • short, violent, small explosion • tephra, ash clouds, and pyroclastic flows Santiaguito volcano in Guatemala

  34. Kinds of Volcanic Eruptions • Pelean • large quantity of gas, dust, ash and lava fragments • pyroclastic flows • one of the most dangerous - tremendous destruction Mont Pelee

  35. Kinds of Volcanic Eruptions • Plinian • largest and most violent • propels pyroclastic material as high as 30 miles • huge amount of tephra • extremely fast moving lava Mt. St. Helens

  36. Effects of Eruptions • Lava • Destroys whatever is in its path • Usually not harmful to humans

  37. Effects of Eruptions • Gas • Some are poisonous • Acid rain

  38. CAMEROONS… Africa carbon dioxide poisoning Sulfur banks

  39. Effects of Eruptions • Pyroclastics • Collapse buildings • Breathing problems • Kills vegetation • Suffocates and buries animals & people

  40. Effects of Eruptions • Pyroclastic flow • Superheated gas and debris rush down side of volcano • faster than 700 km/hour, higher than 1000 degrees C

More Related