volcanoes n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
VOLCANOES PowerPoint Presentation
Download Presentation
VOLCANOES

Loading in 2 Seconds...

play fullscreen
1 / 77

VOLCANOES - PowerPoint PPT Presentation


  • 201 Views
  • Uploaded on

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 .

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - 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 • water vapor, carbon dioxide, sulfur dioxide • Composition of Magma

    19. Factors that control type of eruption Trapped gases (water vapor, carbon dioxide, sulfur dioxide Composition of Magma Low silica basaltic magma quiet eruption • Gases can escape easily less pressure quiet eruption

    20. Factors that control type of eruption Trapped gases (water vapor, carbon dioxide, sulfur dioxide 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 • Composite (Stratovolcanoes) • Explosive eruptions • Andesitic or rhyolitic magma • Can switch from quiet to explosive forming layers of tephra and lava • Steep sided • Tall • Mt. St. Helens

    27. Types of Volcanoes • Cinder cone volcano • Explosive eruptions • Small in size • Steep sided loosely packed • Short lived • Paricutin

    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