Plate Tectonics Listen to Plate tectonics Listen to Earthquake notes

1.  theory of plate tectonics-Earth’s crust and part of the upper mantle are broken into sections.

2.  plates-the sections of the lithosphere

3.  lithosphere-the crunchy part of the Earth, is the crust and the very top of the mantle

4.  asthenosphere-the gooey, plastic like, top part of the mantle that the lithosphere slides upon

5.  plate boundaries-the edges of plates, where they meet.

6.  convection currents inside the Earth are believed to cause the movement of the plates.

7.  convection current is the heating, rising, cooling, and sinking of magma.  As magma gets heated it becomes less dense which causes it to rise upward through the mantle. As it cools, it sinks back downward.  The rising and falling creates a current in the magma.

8.  three movements of plates-towards each other, away from each other, and past each other like cars on a highway

9. If one boundary changes, it will cause changes at other boundaries.

10.  divergent boundary-when two plates move AWAY from each other, ß à. 

11. divergent boundaries cause mid-ocean ridges!!

12. new crust is created by divergent boundaries, mid-ocean ridges

13. If new crust is created, old crust must be recycled by the Earth.

14. convergent boundary-when two plates come together, àß.

15.  convergent boundaries come together, denser oceanic plates/crust will sink beneath continental crust

16.  subduction zone-where oceanic plates goes down into the mantle.

17.  volcanoes can form above subduction zones

18.  deep-sea trenches are formed at convergent boundaries of two ocean plates.

19.  subducted plates melt creating new magma.  New magma can cause volcanoes or be used to form new mid-ocean ridges.

20. mountain ranges-when continental plates converge, they will crumple up.

21.  transform boundaries-where two plates slide past each other.

22.  Earthquakes occur at convergent boundaries and transform boundaries.

23.  San Andreas Fault-a transform boundary in California that causes lots of earthquakes.

24.  seismic waves- energy release as rocks move and break in the crust during an earthquake

25.  fault-area where rocks break and move because of plate movement

26.  faults can cause breaks and shifts in rock layers.




Earthquake and volcano notes

27. focus-the exact point where the energy is released during an earthquake, seismic waves travel outward from the focus.

28.  earthquakes produce three types of seismic waves, Primary, Secondary, and Surface waves

29.  Primary waves move the fastest

30.  Surface waves cause the most damage!!!

31. epicenter-surface location above the focus, where the earthquakes energy reaches the surface and spreads outward like a ripple of surface waves.

32. seismograph –instrument used to measure Seismic waves from earthquakes

33. seismologists -Scientists who study earthquakes and seismic waves

34. magnitude is a measure of the energy released by an earthquake.

35. Richter magnitude scale is used to describe the strength of an earthquake Each magnitude is 10 times stronger than the last.  Magnitude 2 is 10 times stronger than a magnitude 1 and a magnitude 3 is 100 times stronger than a 1.

36. tsunami-ocean waves caused by earthquakes, can be as large as 30 meters tall.

37.  volcano is an opening in Earth that erupts gases, ash, and lava

38. Volcanic mountains form when layers of lava, ash, and other material build up around these openings

39. Earth has more than 600 active volcanoes

40..volcanoes can be active, dormant (sleeping) or extinct (dead)

41. magma reaches Earth’s surface and flows out through an opening called a vent

42. crater the steep walled depression around a vent.

43. Ring of Fire is an area of frequent earthquakes and volcanic eruptions encircling the basin of the Pacific Ocean.  It follows the plate boundaries.

44. fault-block mountains are formed by huge faults

45.  Rift valleys and mid-ocean ridges are cause by divergent plates.

46. The Indian plate and Asian plate boundary is a convergent boundary.  It is moving at 5 cm per year causing the Himalayan Mountains to keep growing.

47. strike-slip faults are found along divergent boundaries moving in opposite directions.

48. scientists can measure the movement of plates using satellites and lasers.

49.  Hawaii is moving towards Japan at 8.3 cm per year.

50.  three types of plate boundaries are convergent, divergent, and transform.