1. Dynamic Earth Topics: -Earth’s Interior -Continental Drift -Seafloor spreading -Plate Tectonics -Earthquakes & Epicenters

2. Earth’s Interior As depth increases so does: -pressure -temperature -density

4. Earth’s Interior Crust - outer thin rock layer –Mostly silicon and magnesium  Oceanic: thin; basalt rock (dense)  Continental: thick, granite rock (less dense)

5. Earth’s Interior Mantle – thickest layer of plastic molten rock –Mostly silicon and magnesium  asthenosphere: upper part; where convection currents are found

6. Earth’s Interior Outer core -iron and nickel -liquid due to intense heat -S waves cannot travel through Inner core -iron and nickel -solid due to intense pressure

9. Continental Drift Continents were once joined together Evidence: -jigsaw fit of continental coastlines -matching geologic features (Mts) across continents -fossils of tropical plants found in continents now in polar regions -fossils of the same species found across oceans

10. Seafloor spreading Age of rocks at mid ocean ridge increase as you move away from ridge Magnetic mineral alignment in basalt (igneous rock) shows poles reversal  forms mirror image on both sides of MOR

12. Plate Tectonics Driven by convection currents in mantle  caused by Density Differences: heat from Earth’s interior causes hot, less dense magma to rise and cool, more dense magma to sink

13. Lithospheric plates slide along with the moving magma Plate boundary: where one plate makes contact with another  earthquakes and volcanoes occur at zones of crustal activity (boundaries)

14. Converging Plate Boundary Plates collide  Continent to Continent: mountain building -uplift of rock: oceanic fossils seen on mts Continent to oceanic: dense oceanic crust sink below continental crust -subduction zone -volcanoes form on continent

15. Diverging Plate Boundary Plates move apart Ex: mid ocean ridge New crust is formed

16. Transform Plate Boundary Plates slide past each other Cause rocks to fault (crack) -produces Earthquakes

17. Hot Spots Form volcanic islands (Hawaii) Stationary plume of rising magma As lithospheric plate moves over hot spot, magma pushes through crust Islands older the further away from hot spot

18. Earthquakes & Epicenters Stress builds up and causes rock to shift Energy released as seismic waves: -P Wave: travels quickly through solids and liquid layers of Earth -S Wave: travels slower though solids but NOT liquid layer (outer core)

19. Locating the Epicenter One seismic station gives you its distance from epicenter but no direction 3 seismic stations are required to locate

21. Finding difference in arrival time Given the arrival times of each wave, use their difference to determine distance traveled The distance from Albany, New York, to the epicenter of an earthquake is 5600 km. Approximately how much longer did it take for the S-wave to arrive at Albany than the P-wave? a. 4 minutes and 20 seconds b. 16 minutes and 10 seconds c. 9 minutes and 0 seconds d. 7 minutes and 10 seconds

23. Finding Travel Time/distance Given distance from epicenter, you can find how long it takes a P or S wave to travel to that seismic station Or you can find the distance the wave traveled based on how long it took the wave to travel there Approximately how long does an earthquake P-wave take to travel the first 6500 kilometers after the earthquake occurs? 6.5 min8.0 min 10.0 min18.5 min In 8 minutes, an earthquake P-wave travels a total distance of 2,100 km 6,600 km 4,700 km 11,300 km

24. Calculating Arrival Time If you know how long it takes one wave type to travel a given distance, you can find out -the time the earthquake happened or -the arrival of the other wave type

25. A seismic station recorded an earthquake with an epicenter distance of 4,000 kilometers. If the origin time of the earthquake was 11:00 a.m., what time did the P-wave arrive at the seismic station? 10:53 a.m.11:05 a.m. 11:07 a.m.11:12 a.m.

26. An earthquake's P-wave arrived at a seismograph station at 02 hours 40 minutes 00 seconds. The earthquake's S-wave arrived at the same station 2 minutes later. What is the approximate distance from the seismograph station to the epicenter of the earthquake? 1,100 km2,400 km 3,100 km4,000 km

27. An earthquake occurs at 12:02 p.m. A seismic station records the first S- wave at 12:19 p.m. Which set of data shows the approximate arrival time of the first P-wave and the distance to the epicenter? a. 12:11:25 p.m. and 4000 km b. 12:11:25 p.m. and 6000 km c. 12:19:40 p.m. and 4000 km d. 12:19:40 p.m. and 6000 km

28. Tsunami Underwater Earthquake pushes water onto shore Wave height grows at it approaches shore