4.4 volcanic eruptions

  • 387 views
Uploaded on

 

More in: Technology , Education
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
No Downloads

Views

Total Views
387
On Slideshare
0
From Embeds
0
Number of Embeds
1

Actions

Shares
Downloads
24
Comments
0
Likes
1

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n
  • \n

Transcript

  • 1. Volcanic Eruptions Mr. Silva
  • 2. Vocabulary
  • 3. Vocabulary• Mafic lava- dark in color and is rich in magnesium and iron.
  • 4. Vocabulary• Mafic lava- dark in color and is rich in magnesium and iron.
  • 5. Vocabulary• Mafic lava- dark in color and is rich in magnesium and iron.• Felsic lava- lighter in color when cools, high in silica.
  • 6. Vocabulary• Mafic lava- dark in color and is rich in magnesium and iron.• Felsic lava- lighter in color when cools, high in silica.
  • 7. Vocabulary• Mafic lava- dark in color and is rich in magnesium and iron.• Felsic lava- lighter in color when cools, high in silica.• Pahoehoe- (puh-HOY-hoy) wrinkles that are formed when lava cools rapidly.
  • 8. Vocabulary• Mafic lava- dark in color and is rich in magnesium and iron.• Felsic lava- lighter in color when cools, high in silica.• Pahoehoe- (puh-HOY-hoy) wrinkles that are formed when lava cools rapidly.
  • 9. Vocabulary• Mafic lava- dark in color and is rich in magnesium and iron.• Felsic lava- lighter in color when cools, high in silica.• Pahoehoe- (puh-HOY-hoy) wrinkles that are formed when lava cools rapidly.• Aa- (AH-ah) refers to the sharp, blocky texture of volcanic rock.
  • 10. Vocabulary
  • 11. Vocabulary• Pillow lava/Pillow basalts- round blobs of lava that separate and cool underwater.
  • 12. Vocabulary• Pillow lava/Pillow basalts- round blobs of lava that separate and cool underwater.
  • 13. Vocabulary• Pillow lava/Pillow basalts- round blobs of lava that separate and cool underwater.• Pyroclastic material- particles of lava that fly into the air when eruption occurs.
  • 14. Vocabulary• Pillow lava/Pillow basalts- round blobs of lava that separate and cool underwater.• Pyroclastic material- particles of lava that fly into the air when eruption occurs.
  • 15. Vocabulary• Pillow lava/Pillow basalts- round blobs of lava that separate and cool underwater.• Pyroclastic material- particles of lava that fly into the air when eruption occurs.• Volcanic ash- Particles less than 2mm
  • 16. Vocabulary• Pillow lava/Pillow basalts- round blobs of lava that separate and cool underwater.• Pyroclastic material- particles of lava that fly into the air when eruption occurs.• Volcanic ash- Particles less than 2mm
  • 17. Vocabulary• Pillow lava/Pillow basalts- round blobs of lava that separate and cool underwater.• Pyroclastic material- particles of lava that fly into the air when eruption occurs.• Volcanic ash- Particles less than 2mm• Volcanic dust- Particles less than .25mm
  • 18. Vocabulary• Pillow lava/Pillow basalts- round blobs of lava that separate and cool underwater.• Pyroclastic material- particles of lava that fly into the air when eruption occurs.• Volcanic ash- Particles less than 2mm• Volcanic dust- Particles less than .25mm
  • 19. Vocabulary• Pillow lava/Pillow basalts- round blobs of lava that separate and cool underwater.• Pyroclastic material- particles of lava that fly into the air when eruption occurs.• Volcanic ash- Particles less than 2mm• Volcanic dust- Particles less than .25mm• Lapilli- Particles less than 64 mm
  • 20. Vocabulary
  • 21. Vocabulary• Volcanic bombs- clot of lava that spins through the air and cools.
  • 22. Vocabulary• Volcanic bombs- clot of lava that spins through the air and cools.
  • 23. Vocabulary• Volcanic bombs- clot of lava that spins through the air and cools.• Volcanic block- largest pyroclastic particle that blast from the fissure or vent.
  • 24. Vocabulary• Volcanic bombs- clot of lava that spins through the air and cools.• Volcanic block- largest pyroclastic particle that blast from the fissure or vent.
  • 25. Vocabulary• Volcanic bombs- clot of lava that spins through the air and cools.• Volcanic block- largest pyroclastic particle that blast from the fissure or vent.• Shield Volcano- covers a wide area and generally result from lava eruptions.
  • 26. Vocabulary• Volcanic bombs- clot of lava that spins through the air and cools.• Volcanic block- largest pyroclastic particle that blast from the fissure or vent.• Shield Volcano- covers a wide area and generally result from lava eruptions.
  • 27. Vocabulary• Volcanic bombs- clot of lava that spins through the air and cools.• Volcanic block- largest pyroclastic particle that blast from the fissure or vent.• Shield Volcano- covers a wide area and generally result from lava eruptions.• Cinder Cone- formed from explosive eruption.
  • 28. Vocabulary• Volcanic bombs- clot of lava that spins through the air and cools.• Volcanic block- largest pyroclastic particle that blast from the fissure or vent.• Shield Volcano- covers a wide area and generally result from lava eruptions.• Cinder Cone- formed from explosive eruption.
  • 29. Vocabulary• Volcanic bombs- clot of lava that spins through the air and cools.• Volcanic block- largest pyroclastic particle that blast from the fissure or vent.• Shield Volcano- covers a wide area and generally result from lava eruptions.• Cinder Cone- formed from explosive eruption.• Composite Volcano- results from altering layers of pyroclastic material and lava.
  • 30. Vocabulary
  • 31. Vocabulary• Stratovolcanoes- also known as composite volcanoes, highest volcanic mountains.
  • 32. Vocabulary• Stratovolcanoes- also known as composite volcanoes, highest volcanic mountains.
  • 33. Vocabulary• Stratovolcanoes- also known as composite volcanoes, highest volcanic mountains.• Crater- funnel shape around the vent of the volcano.
  • 34. Vocabulary• Stratovolcanoes- also known as composite volcanoes, highest volcanic mountains.• Crater- funnel shape around the vent of the volcano.
  • 35. Vocabulary• Stratovolcanoes- also known as composite volcanoes, highest volcanic mountains.• Crater- funnel shape around the vent of the volcano.• Caldera- basin in the crater that is created when slippage occurs.
  • 36. Volcanic Eruptions• The lava that erupts from volcanoes allows us to determine firsthand the material that emerges from the mantle.• Scientist has discovered that there are two general types of lava. – Mafic lava – Felsic lava
  • 37. Mafic Lava• Dark in color when hardens.• Rich in Magnesium and Iron.• Forms much of the ocean crust.• When crust cools rapidly, surface will form a crust.
  • 38. Felsic Lava• Lighter in color when hardens• Common in continental crust• Contains much silica, with lesser amounts of iron and Magnesium
  • 39. Rock Formations• When mafic lava cools and forms wrinkles there called pahoehoe (puh-HOY-hoy)• Can break into jagged chunks to form aa (Ah-ah)• When lava flows into the ocean and cools rapidly, it often separates and forms pillow lava.
  • 40. Kinds of Eruptions• The kind of lava that reaches the surface determines the force the volcano will erupt.• Lava that contains large amounts of trapped gases produces a more explosive eruption of lava.
  • 41. Oceanic Volcanoes• Usually produced by mafic lava.• Mafic lava is very hot and thin, and flows like almost as easy as water.• Gases escape easier from mafic lava, so eruptions are usually quiet.• Will flow from the opening like a red hot river.
  • 42. Continental Volcanoes• Most commonly comprised of felsic lava.• Tends to be cooler and thicker.• Contains large amounts of trapped gases, mostly water vapor and carbon dioxide.• When fissure or vent opens, gases escape explosively sending molten particles shooting into the air.
  • 43. Volcanic Rock Fragments• Felsic lava explode throwing pyroclastic material into the air.• Formed when lava cools too fast or is sprayed into the air and solidifies. – Volcanic ash – Volcanic dust – Lapilli (luh-PIL-ie) – Volcanic bombs – Volcanic blocks
  • 44. Volcanic Rock Fragments• Volcanic ash • Volcanic dust – Particles less than 2mm – Particles less than .25 mm
  • 45. Volcanic Rock Fragments• Lapilli • Volcanic bomb – Particles less than 64mm – Round or spindle shape
  • 46. Volcanic Rock Fragments• Volcanic Blocks – Largest pyroclastic material, can be as big as a house!
  • 47. Volcanic Features• Volcanic activity produces a variety of characteristic features on the earth.• The lava and pyroclatic material ejected during eruption can build up around the vent.• These piles are known as volcanic cones; they are classified into three different types. – Shield Volcano – Cinder Cones – Composite Volcano
  • 48. Shield Volcano• Covers a wide area• Generally results from lava eruption• Layers of hot mafic lava flow out around the vent, harden, and slowly build up to form a cone.• The Hawaiian Islands are a chain ofshield volcanoes.
  • 49. Cinder Cone• Made up of solid fragments ejected from the volcano.• Most cinder cones have very steep slopes, often close to 40 degrees.• Rarely more than a few hundred meters high.
  • 50. Strato / Composite Volcano• Many volcanoes have both quiet and explosive eruptions.• Composite volcanoes are formed as a result of alternating layers of lava and pyroclastic material.• Also known as stratovolcanoes
  • 51. Craters/ Calderas• A crater is a funnel-shaped pit at the top of the volcanic vent .• Formed when material is blown out of the volcano by explosion.• Calderas are formed when slippage or sinking occurs in the crater.
  • 52. Super Volcanoes• Yellowstone National Park 23
  • 53. Predicting Volcanic Eruptions• Volcanic eruptions can be one of earth’s most destructive natural phenomena.• Scientist are still making progress toward increase there abilities in predicting volcanic activity.• Scientists use instruments much like the one they use with earthquake prediction.
  • 54. Predicting Volcanic Eruptions• Things they look for: – Temperature changes within the rock – Fracturing of rocks from pressure build-up – Increase in # earthquake around volcano – Increase is strength of earthquakes – Bulging surface – Change in gases given off by the volcano in the area