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Earthquakes & Volcanoes. Unit 4: Tectonics NOTES page 3. ©Mark Place, 2008-2009 www.LearnEarthScience.com Revised 2010. Key Concepts & Questions. What is the driving force behind crustal movement ?. Convection Currents in the Mantle. Key Concepts & Questions.
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Earthquakes & Volcanoes Unit 4: Tectonics NOTES page 3 ©Mark Place, 2008-2009 www.LearnEarthScience.com Revised 2010
Key Concepts & Questions • What is the driving force behind crustal movement ? Convection Currents in the Mantle
Key Concepts & Questions • What provides the energyfor this force? radioactive decay
Key Concepts & Questions • What are the different types of earthquake waves? And how do they travel?
Key Concepts & Questions p-waves Travel Through Anything primary waves push-pull waves
Key Concepts & Questions s-waves Travels Through Solids Only secondary waves shear waves
Key Concepts & Questions Where can most earthquake epicenters and volcanoes be found? at plate boundaries "Ring of Fire"
Key Concepts & Questions To find an earthquake’s epicenter a seismologist must have data from at least how many locations?
Key Concepts & Questions How can scientists infer the properties of Earth’s interior?
by observing earthquake waves
Remember: P-Waves go through everything. S-Waves do not got through liquids-will not go through outer core, so outer core is a liquid.
Key Concepts & Questions How do scientists know that Earth’s inner core is solid?
by the refraction (bending) of P-waves
Also meteorites from space contain solid iron & nickel. Scientists believe the Earth’s interior is also solid iron & nickel.
Key Concepts & Questions What can people do to protect themselves during an earthquake? get under desk/table stand against interior wall stay away from windows
What can people do to protect themselves before an earthquake? Have an emergency evacuation plan. Prepare food and water. Build reinforced structures.
Key Concepts & Questions What is the Richter Scale and how is it used?
a measure of earthquake strength based on a scale from 1-10 Remember the new MERCALLI SCALE measures damage from I - XII
EarthquakeReference TableQuestions Please get out your ESRT p. 11!
If a p-wave arrives five minutes before the s-wave arrives, how many kilometers from the epicenter is a location? 3600 kms
If a p-wave arrives at 12:10:00 and the s-wave arrives at 12:16:20, how many kilometers from the epicenter is a location? 4800 kms
An earthquake epicenter is 2600 kilometers from a location. If the p-wave arrives at 9:00:20, what time will the s-wave arrive? 9:04:20
An earthquake epicenter is 5200 kilometers from a location. If the s-wave arrives at 1:20:20, what time did the p-wave arrive? 1:13:20
If a p-wave arrives 6 mins after an earthquake occurs, how many kilometers is the location from the epicenter? How long after the p- wave arrives will the s-wave arrive? 3200 kms 4:40 later
Plate Tectonics Tectonics NOTES page 6 ©Mark Place, 2008-2009 www.LearnEarthScience.com
What is the Theory of Continental Drift? • Alfred Wegener, 1915 • The continents were once a super-continent called Pangea. • the continents are plowing through the ocean floors---most people didn’t believe this
What evidence supports this theory? • Africa & South America look like they fit together • similar fossils, rocks, and glacial striations
What is the Theory of Plate Tectonics? • Earth's crust is made up of plates that ride on top of the asthenosphere • The plates move due to convection currents in the mantle
What evidence supports this theory? • distribution of earthquakes and volcanoes • sea-floor spreading
How do oceanic and continental crust compare with regard to thickness and density? high low thin thick
What are the primary rocks which make up the continental and oceanic crusts? Low-density, light- colored, coarse- grained, felsic, igneous rock High density, dark- colored, fine-grained, mafic igneous rock granite basalt
What are these types of plate boundaries? What are the key characteristics for each? Give an example of where each can be found.
oceanic-continental convergent boundary trenches, volcanoes, deep earthquakes Peru-Chile Trench
continental-continental convergent boundary mountain building Himalayas
transform fault slide past one another shallow earthquakes San Andreas Fault
divergent plate boundary new crust is made Mid-Atlantic Ridge
What happens to the age of oceanic crust as distance increases from a ridge?
Explain how magnetic data can be used to show that oceanic crust is diverging at ridges. Use the diagram below to help explain your answer. • as new crust is made at ridges, the ferrous minerals (Fe) align according to where the magnetic poles are located • same pattern on opposite sides of the ridge • proves sea-floor spreading