Earthquake Internet Project

Compared to the rest of the planet, the Earth's solid crust is incredibly thin - like the skin of an apple. If you started drilling in your backyard, you would go through 25-40 miles of this solid rock - which sounds like a lot, except that after that you would hit 1,800 miles of very hot liquefied metal before reaching the planet's solid core.

Check out this site to learn more about the layers of the Earth:

http://volcano.und.edu/vwdocs/vwlessons/lessons/Earths_layers/Earths_layers2.html

So the land we walk on is really just a thin, brittle crust floating on a huge ball of molten goo. Or, more accurately, it's a bunch of pieces of crust, called plates, sliding around on goo (very slowly), rubbing against each other. Where these plates meet, you'll find faults -- breaks in the Earth's crust where the blocks of rock on each side are moving in different directions, in sudden starts and stops.

Land along faults will stay stationary for years, even decades at a time, building up pressure When enough pressure builds, the land will shift abruptly and with great force. The result is an earthquake.

For more information about what causes earthquakes, check out How Earthquakes Work

Fast Facts

• There are about 8,000 earthquakes a day. That's one every 11 seconds!
• Only 1 in 5 earthquakes can be felt by people, and only 1 in 5,000 causes any damage.
• The plates on either side of the San Andreas Fault Zone slide past each other at a rate of about 2 to 4 inches per year. This is about the same rate at which fingernails grow.
• Assuming this rate of movement continues, Los Angeles and San Francisco could be right next to each other in approximately 15 million years.
• Between 1975and 1995, there was a significant earthquake in every state except Florida, Iowa, North Dakota, and Wisconsin.
• On average, Alaska has a magnitude 8 or greater earthquake every 14 years. It has had 12 7.0 quakes in the past 30 years alone.

(Source for all fast facts is USGS)

WebQuest Online Exercise
In this journey around the Web, we'll discover what causes earthquakes, how scientists can figure out their exact location, where they occurred last week and much, much more! Click on the Web site(s) after each question to find your answer.

1.    Around 1912, German meteorologist Alfred Wegener developed a theory called continental drift. He believed that about 225 million years ago, giant landmasses gradually shifted and broke apart to form the continents as we know them today. How many original "supercontinents" did Wegener's theory of continental drift assume?

http://www.exploratorium.edu/faultline/index.html

2. The Earth's crust is made up of a series twelve interconnected landmasses are called tectonic plates. What are the major plates that affect the United States?
   • www.usatoday.com/graphics/news/gra/quake/frame.htm
   • www.bbc.co.uk/science/hottopics/naturaldisasters/earthquakes.shtml
     (scroll down and click through the "How Earthquakes Happen" animation)
   •  
3. Check out this hazard map showing probability for earthquakes. Why do you think California has so many earthquakes but Florida doesn't? In what hazard zone is your home located?
   • www.usatoday.com/graphics/news/gra/earthquakemap/frame.htm
4. What is considered to be the most destructive earthquake in history? When did it occur, where was it, what was its magnitude and how many people died?
   • http://neic.usgs.gov/neis/eqlists/eqsmosde.html
5. What are the three basic types of plate boundaries? Describe each briefly.
   • http://www2.nature.nps.gov/geology/usgsnps/pltec/pltec3.html
6. What are tsunamis, what causes them and how fast do they travel?
   • www.usatoday.com/weather/tg/wtsunami/wtsunami.htm
7. What are the two types of energy waves created by an earthquake and how do they differ? Which type of wave travels faster?

http://www.thetech.org/exhibits/online/quakes/waves/p&s_waves.html

http://www.thetech.org/exhibits/online/quakes/grams/

8. How much more energy is released by a 7.2 earthquake than by a 6.2 earthquake?
   • http://neic.usgs.gov/neis/eqlists/eqstats.html
9. Where did most of the earthquakes happen last week?
   • http://earthquake.usgs.gov/recenteqsww/index.html (World map with clickable regions)
   • http://earthquake.usgs.gov/recenteqsUS (U.S. map with clickable regions)
10. Can scientists predict earthquakes?
    • www.usatoday.com/news/science/geology/2001-03-04-quake-predict.htm
11. How do scientists know where an earthquake actually occurred?
    • science.howstuffworks.com/earthquake5.htm
12. Draw a diagram of each type of fault. Include a short description of each.  Make sure you scroll down and play the animation.

http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/tectonics_landforms/faulting_p2.html

13. What is the Pacific Ring of Fire? Why do so many volcanoes and Earthquakes take place in this region?

http://pubs.usgs.gov/gip/dynamic/fire.html

http://www.see.leeds.ac.uk/structure/dynamicearth/subduction/ringofire/index.htm

http://www.pbs.org/wnet/savageearth/hellscrust/html/sidebar3.html