1. What are earthquakes? 1. • • Earthquakes are movement of earth’s crust caused by plates shifting and releasing stored energy Rocks on either side of a fault snag and build up pressure When the rocks break ... shake, rattle and roll! 2. What are seismic waves? 2. Seismic waves are shock waves in the earth caused by an earthquake. 3. What are P waves? 3. P waves are primary waves. They are fast and longitudinal ( push and pull forces) • P waves are the to 'arrive' at a seismic station. The P wave can move through solid rock and fluids, like water or the liquid layers of the earth. It pushes and pulls the rock it moves through just like sound waves push and pull the air. 4. What are S waves? 4. S waves are secondary or shear waves. They are slower. S waves are transverse- move from side to side. S waves move rock particles up and down, or side-to-side— perpendicular to the Direction of the wave. 5. What are L waves? 5. L waves are “love waves” • • Named after a British scientist who calculated a mathematical model for a wave. L Waves are the fastest waves and move from ground to side to side. In other words, they are P or S waves that hit the surface. 6. What is the focus of an earthquake? 7. What is the epicenter? 6. The focus is where rocks first break and move. 7. The Epicenter is the point on earth’s surface directly above the focus. Earthquakes 8. What is a seismograph? 8. A seismograph is an instrument used to record seismic waves. Earthquake Scales 9. What is the Richter Scale? 9. A Richter Scale measures the total energy released by an earthquake b) +1 means x32 Earthquake Scales 10. What is 10. The Mercalli Intensity Scale is the Mercalli Intensity Scale? a scale that measures the intensity of an earthquake. The scale quantifies the effects of an earthquake on the Earth's surface, humans, objects of nature, and man-made structures on a scale of I through XII, with I denoting a weak earthquake and XII one that causes almost complete destruction. Earthquake Zones 11. Where are the 3 major earthquake zones? 11. • Ring of Fire- is located around the edge of the Pacific Ocean. • Mid-Atlantic Ridge- this zone is caused by sea floor spreading • The Mediterranean –Asiatic Belt- occurs because continental plates are colliding. Earthquake Evidence 12. Describe 12. Ground level earthquake evidence is side to side or up ground and down shifts of the ground. level The earth has moved mostly earthquake slow and steady and is called evidence creep Earthquake Evidence 13. Describe 13. There are 5 descriptions: landscape • Slide – rapid down slope movement of soil, debris, & evidence of rock earthquakes • Scarp – cliff made by uplifted . or subsided earth Earthquake Evidence 13. 13. • Fissures – long cracks in soil or rock • Tsunami – an ocean wave caused by earthquakes a) can be 30m high at the shore • Buildings on loose soil have more damage. Volcanoes 14. What is a volcano? 14. A volcano is any opening in the earth’s crust that release molten rock. Volcanoes 15. What is a vent? 16. What is a crater? 15. An opening through which material reaches the surface 16. A crater is a hollowed out area in the top of a volcano Volcanoes 17. What is the pipe? 17. The pipe is a long crack through which magma moves 18. What is the magma chamber? 18. A chamber with a pocket of magma. Volcanoes 19. What is an 19. An active volcano has active erupted during the last volcano? century. 20. What is a dormant volcano? 20. A dormant volcano has not erupted for hundreds of years, but it believed that it has the ability to erupt. http://www.geocodezip.com/v2_activeVolcanos.asp Volcanoes 21. What is an 21. A volcano is considered extinct extinct if it has not volcano? erupted for thousands of years. http://hvo.wr.usgs.gov/volcano es/maunakea/ Volcanoes 22.List the sequence of events when a volcano erupts? 22. Lava flows out –usually gently and quietly 2) Then an explosion of debris occurs. The following are products of a volcano • pyroclasts – fragments of broken rock from a volcano • ash – hot fine-grained material • bombs – large molten or semimolten chunks Volcanoes 23. What are cinder cone volcanoes? 23. A cinder cone formed from ash and cinders in explosive eruptions. Cinder cones volcanoes are smaller, coned shaped, and steep slopes. Example: • Paricutín, Mexico Volcanoes 24. What are shield volcanoes? 24. Shield volcanoes are from from lava flow eruptions. They have broad with gentle slopes. • An example is Muana Loa, Hawaii Volcanoes 25. What are composite volcanoes? 25. Composite volcanoes are formed from alternating layers of lava and pyroclasts. Characteristics include: • They are explosive and have lava eruptions • They are large with steep slopes Examples: Mt. Fuji, Japan & Mt. St. Helens, Washington 26. Case study: Pompeii 26. •79 CE •Site was not discovered until 1748 •Provided archeologists extraordinary details about daily life in Roman Empire •Some believe that volcano took 2 months to completely bury the town as people were “found” wearing winter clothing in the summer, dates of minted coins and letters •Populist tourist site in S. Italy 27. Case study: Mt. St. Helen 27. •Erupted 05/18/1980. Caused by an earthquake on 03/20/1980. •Most deadliest and costly volcano in US history. •“Glacier mountain” •Due to the eruption, at the top of the mountain is a 1 mile long horseshoe crater. •Volcano “steamed” until January 2008 Igneous Rock Features 28. What are batholiths? 28. Large intrusive igneous rock body that forms when magma being forced upward toward Earth’s crust cools slowly and solidifies underground. 29. What is a dike? 29.Magma that is forced into a crack that cuts across layers and hardens. 30. What is a volcanic neck? 30. Solid igneous core of a volcano left behind after the softer cone has been eroded. 31. What is a Igneous caldera? 31. Large, circularRock Features shaped opening formed when the top of a volcano collapses. Crater Lake is an example