1. What are Earthquakes?

2. Earthquakes Sudden release of energy in the crust – Tremors – small shaking of the crust Today’s earthquakes – About 2 Earthquakes occur every second. – But most are too small to be felt. – Most Earthquakes occur near plate boundaries – Deepest earthquakes occur on subduction zones (convergent boundaries)

3. Where Does an Earthquake Start? FOCUS – STARTING POINT OF AN EARTHQUAKE BELOW THE SURFACE EPICENTER – POINT DIRECTLY ABOVE THE FOCUS ON THE SURFACE

4. Damage Caused by Earthquakes Faults **** Most death’s and injuries are caused by falling buildings (Earthquakes don’t kill people buildings kill people). Broken gas lines can lead to fires. Broken water pipes compound the problem. because there is less available to put out the fires. Landslides and mudflows Liquefaction of soil (soil becomes so unstable that it moves like a fluid) Tsunamis – extreme ocean waves caused by earthquakes Tsunami detection system

5. Damage is Amplified Create Your Own Earthquake and Building Structures: compare damage Create Your Own Earthquake and Building Structures: compare damage Damage will be more severe when building on loose sediments The loose sediments will move more and result in liquefaction (soil acting as a fluid) – Houses could sink into the loose sediments

6. Damage Prevention Build on strong solid bedrock Build Earthquake proof buildings – buildings that have internal gyroscopes which allows the building to move with the lithosphere. Securely mount art to walls. Avoid windows and move under a table to prevent being hit by falling objects

7. Earthquake Preparedness Follow damage prevention plan Have a short food and water supply Evacuation Plan Move to higher ground to avoid Tsunami

8. Measuring Seismic Waves Seismograph – machine that measures seismic waves at a given location Seismogram – record sheets of waves created by the seismograph

9. Scales used to Report Earthquakes Mercalli Measures strength of an Earthquake according to the amount of damage done Measures Intensity (by how intensely it was felt) Scale ranging between I-XII Not always accurate b/c some locations may incur severe dmg even when the EQ was not that strong (If buildings and structures are built on loose sediments then eqs are amplified Intensity measurements of the 1906 San Francisco Earthquake Intensity measurements of the 1906 San Francisco Earthquake Richter Measures MAGNITUDE of EQ based on Seismic waves

10. Mercalli Scales

12. Scales used to Measure E.Q’s

14. http://www.classzone.com/books/earth_science/terc/content/visualizations/es1002/es1002pag e01.cfm?chapter_no=visualization http://www.classzone.com/books/earth_science/terc/content/visualizations/es1002/es1002pag e01.cfm?chapter_no=visualization ** p & s waves animations http://www.classzone.com/books/earth_science/terc/content/visualizations/es1009/es1009pag e01.cfm http://www.classzone.com/books/earth_science/terc/content/visualizations/es1009/es1009pag e01.cfm Shadow zone http://www.thetech.org/exhibits_events/online/quakes/waves/p&s_waves.html Wave slinky and rope animation http://www.wwnorton.com/college/geo/egeo/flash/8_2.swf P and s waves http://earthquake.usgs.gov/learn/animations/animation.php?flash_title=Shadow+Zone+ Flash+Animation&flash_file=shadowzone&flash_width=220&flash_height=300 Shadow zone http://www3.interscience.wiley.com:8100/legacy/college/skinner/0471152285/anim ations/animations/mod_5/seismic_waves.html Wave animations and shadow zone