The document summarizes key concepts in earth science, including: 1) Constructive forces build up the earth's surface while destructive forces wear it away. 2) The lithosphere consists of tectonic plates that meet at boundaries and glide on the asthenosphere. 3) All continents were once joined in a supercontinent called Pangaea before separating due to sea floor spreading. 4) Sea floor spreading occurs at mid-ocean ridges as new crust is formed and plates move apart.

1. EARTH SCIENCE REVIEW

2. DIFFERENCE BETWEEN
CONSTRUCTIVE AND DESTRUCTIVE
FORCES
 Constructive forces build up the earth’s surface
 Destructive wear away earth’s surface

3. LAYERS OF EARTH
 Lithosphere- consists of crust and top of mantle
 Separates into plates
 Meets at plate boundaries
 Asthenosphere- located under lithosphere; what
the lithosphere glides on top of

4. PANGEA
 All the continents were once joined together in a
super continent
 Continents fit together like puzzle pieces

5. SEA FLOOR SPREADING
 Two oceanic plates moving away from each other
(diverging)
 The ocean floors move like conveyor belts,
moving the continents away from each other
 New crust is formed where the plates are
spreading

6. SEA FLOOR SPREADING AND PLATE
TECTONICS
 Convection currents is the engine that drives the
plates to move

7. TYPES OF PLATE BOUNDARIES
 Convergent
 Divergent
 Transform

9. WHAT HAPPENS WHEN PLATES
COLLIDE?
 Oceanic/Oceanic- the older plate (more dense
plate) will subduct
 Oceanic/Continental- oceanic plate subducts
because it is more dense
 Continental/Continental- forms mountain ranges

10. DEFORMATIONS CAUSED BY
STRESS
 Anticlines
 Synclines
 Plateaus

11. TYPES OF FAULTS
 Strike- Slip Fault
 Reverse Fault
 Normal Fault

12. FOCUS AND EPICENTER
 Focus- point BENEATH Earth’s surface where
rock under stress breaks to cause an earthquake
 Epicenter- point on the surface directly above the
focus

13. SEISMIC WAVES
 P Waves- compress and expand the ground like
an accordion (happen first)
 S Waves- vibrate from side to side and up and
down
 Surface Waves- when waves reach the surface
(cause most damage)

14. SCALES FOR MEASURING
EARTHQUAKES
 Mercalli Scale- rates earthquakes based on
damage
 Richter Scale
 Moment Magnitude scale

15. RISK FACTORS FOR EARTHQUAKES
 Shaking
 Liquefaction
 Aftershocks
 Tsunamis

16. DEVICES TO MONITOR AND DETECT
EARTHQUAKES
 tiltmeter

17. WHERE DO VOLCANOES FORM?
 Convergent boundaries
 Divergent boundaries
 Hot spots

18. TYPES OF VOLCANOES
 Composite
 Shield
 Cinder cone

19. PARTS OF A VOLCANO

20. ACTIVITY OF VOLCANOES
 Active
 Dormant
 Extinct

21. MAGMA AND LAVA
 Magma is molten rock under the ground
 When magma reaches the Earth’s surface, it is
called lava

22. SILICA AND MAGMA’S VISCOSITY
 Silica determines viscosity
 The more silica, the more viscous a substance is
 More silica magma is light colored and is too
sticky to flow far
 Less silica magma flows readily and produces
dark colored lava

23. HOW DOES TRAPPED GAS EFFECT A
VOLCANO’S ERUPTION?
 As magma rises toward the surface, the pressure
decreases and the dissolved gases begin to expand and
exert an enormous force