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Name: ________________________________ Class: _________ Bill Nye- Earthquakes (https://www.youtube.com/watch?v=kT0zDmEvWag) 1. Every year there are _________________ of earthquakes around the worlds. 2. Earthquakes happen when the ____________ move. 3. The Earth’s surface is floating on ______________ rock inside the Earth. 4. As the plates move, they crack. The cracks are called _________________. 5. A _____________________ records ground shaking and prints out a seismograph of the data. 6. In the homemade seismometer experiment, the marble falls ______________________________________________________________ ____________ 7. Lava is molten rock located... a. inside the Earth b. on the Earth’s surface c. in outer space 8. Seismologists find the ______________ of an earthquake by using the data from 3 different seismometer stations. 9. The ____________ Scale compares the size of one earthquake to the size of another. 10. When the ground moves 10 times as much, there is about _________ times as much energy released. EARTHQUAKES How to find an epicenter using triangulation Locating Earthquakes 1. Difference between arrival times of P and S waves is determined. This gives distance to the epicenter from the seismograph. 2. Three seismographs are triangulated to give actual location of the epicenter (Figure above). http://geology.csupomona.edu/drjessey/class/Gsc101/Earthquake.html Practice with Triangulation: Locating an earthquake epicenter You learned that seismologists determine the distance to the earthquake epicenter using the difference between S and P wave arrival times. To locate the epicenter of the earthquake, seismologists use the distance data from 3 different seismographs, and then draw circles that distance away from the station. Where they intersect, that’s the epicenter!! (or close to it) An earthquake was recorded at Stations A, B, and C shown on the map below. Station A reported that the epicenter of the quake was 1500 km from the station. Station B reported a distance of 3500 km. Station C reported a distance of 5000 km. Using a ruler, compass, and the scale below of ¼ inch = 500 km, locate and label the epicenter of the earthquake on this map. ¼ inch = 500 km An earthquake was recorded at Stations A, B, and C shown on the map below. Station A reported that the epicenter of the quake was 2500 km from the station. Station B reported a distance of 5000 km. Station C reported a distance of 6750 km. Using a ruler, compass, and the scale below of ¼ inch = 500 km, locate and label the epicenter of the earthquake on this map. ¼ inch = 500 km Practice with Triangulation: Locating an earthquake epicenter You learned that seismologists determine the distance to the earthquake epicenter using the difference between S and P wave arrival times. To locate the epicenter of the earthquake, seismologists use the distance data from 3 different seismographs, and then draw circles that distance away from the station. Where they intersect, that’s the epicenter!! (or close to it) An earthquake was recorded at Stations A, B, and C shown on the map below. Station A reported that the epicenter of the quake was 2000 km from the station. Station B reported a distance of 2000 km. Station C reported a distance of 4500 km. Using a ruler, compass, and the scale below of ¼ inch = 500 km, locate and label the epicenter of the earthquake on this map. ¼ inch = 500 km An earthquake was recorded at Stations A, B, and C shown on the map below. Station A reported that the epicenter of the quake was 5500 km from the station. Station B reported a distance of 4000 km. Station C reported a distance of 1000 km. Using a ruler, compass, and the scale below of ¼ inch = 500 km, locate and label the epicenter of the earthquake on this map. ¼ inch = 500 km