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Seismology, Volcanology , and without apology, Geology.

Seismology, Volcanology , and without apology, Geology. Seismology. Seismology. Seismology is the study of earthquakes and their effects. When there is an earthquake a great deal of energy is released. This energy travels in the form of waves. Seismology.

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Seismology, Volcanology , and without apology, Geology.

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  1. Seismology, Volcanology, and without apology,Geology.

  2. Seismology

  3. Seismology • Seismology is the study of earthquakes and their effects. • When there is an earthquake a great deal of energy is released. • This energy travels in the form of waves.

  4. Seismology • There are two kinds of seismic waves • Body waves • Surface waves

  5. Body waves

  6. Body waves • Body waves travel through the ground and move very quickly. • There are two kinds of body waves.

  7. Body waves • Body waves travel through the ground and move very quickly. • There are two kinds of body waves. • Primary waves • Secondary waves

  8. Body waves • Primary waves - also called “P waves” • Travel at about 6 km/s (they are the fastest seismic waves) • Can move through both solids and liquids • The ground compresses and stretches in the direction they travel.

  9. Body waves • Secondary waves - also called “S waves” • They travel at about 3.5 km/s (They are the second fastest seismic waves) • Can move through solids but not liquids • They cause the ground to squeeze and stretch at right angles to the wave direction.

  10. Surface waves

  11. Surface waves • Love waves – also called “L waves” • They travel more slowly than body waves but because they travel along the surface of the Earth they cause more damage than body waves.

  12. So? What good is it knowing all that stuff about seismic waves?

  13. Seismology

  14. Seismology • By analyzing seismic waves geologists can figure out a lot about the conditions below the surface of the Earth including the thickness and composition of each layer.

  15. Volcanology

  16. Volcanology • There are three types of volcanoes

  17. Volcanology • Composite Volcanoes • Large cone-shaped volcanoes. • The “classic” volcano image. • The cone shape results from recurring eruptions of ash and lava which builds up layers over time.

  18. Volcanology • Composite Volcanoes • The magma for these volcanoes isvery thick • They form at plate boundaries where subduction is occurring. • These volcanoes can have very explosive eruptions. • Mt. Fuji, Mt St. Helens, and Mt. Vesuvius are composite volcanoes

  19. Composite Volcanoes

  20. Volcanology • Shield Volcanoes • These volcanoes form at weak parts of the Earth’s crust called “Hot Spots” where lava/magma can burst through. • The lava forming these volcanoes is much more fluid than the kind at composite volcanoes.

  21. Volcanology • Shield Volcanoes • The result is non-explosive eruptions and not very steep slopes. But these are the largest volcanoes. • The Hawaiian Islands and the Galapagos Islands are examples of Shield Volcanoes.

  22. Shield Volcanoes

  23. Shield Volcanoes

  24. Shield Volcanoes

  25. Volcanology • Rift Eruptions • These occur where ridges are spreading • Lava comes up through the long cracks • These are not violent eruptions but they can release a lot of lava • The Columbia River Plateau is a 30 m.y. old rift eruption where the lava is about 3 km thick.

  26. Rift Eruptions

  27. Volcanology Q: What comes out of a volcano?

  28. Volcanology Q: What comes out of a volcano? A: Pyroclastic material

  29. Volcanology Q: What comes out of a volcano? A: Pyroclastic material • Ash – sand sized pieces of rock • Steam • Lava • Gas

  30. Volcanology Q: What comes out of a volcano that will most likely kill you?

  31. Volcanology Q: What comes out of a volcano that will most likely kill you? A: The Pyroclastic Flow – a mixture of gas, steam and ash, superheated to over 1000⁰C, and capable of travelling at over 300 km/h.

  32. Volcanology Q: What comes out of a volcano that will most likely kill you? A: A Lahar occurs when the volcano is covered in snow or ice. The mud, water, ash and debris can cover large distances very quickly.

  33. Geology

  34. Geology Three types of rock make up the Earth’s crust.

  35. Geology Three types of rock make up the Earth’s crust. • Igneous • Sedimentary • Metamorphic

  36. Igneous • Igneous rocks are formed when magma cools. • “Ignis” is Latin for “fire.” • About 95% of the Earth’s crust is igneous • There are about 700 different kinds of I.R. • Examples of igneous rocks are granite and basalt.

  37. Igneous(granite)

  38. Igneous(basalt)

  39. Igneous(kimberlite pipe)

  40. Sedimentary • Sedimentary rock is formed from sediments – which are fragments of pre-existing rocks compacted together. • Rocks formed from sediments cover about 80% of the Earth’s land area. • Examples of s.r. include; shale, sandstone, chalk, and conglomerate

  41. Sedimentary • Fossils are found usually only in s.r.

  42. Sedimentary

  43. Metamorphic • Formed from pre-existingrockschanging under heat and pressure. • Examples of m.r. include gneiss, slate, marble and schist.

  44. The Rock Cycle

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