Geology Notes Part 8 What causes earthquakes When

Geology Notes Part 8

What causes earthquakes? • When plates slide past each other, collide, or move part • http: //news. bbc. co. uk/cbbcnews/hi/newsid_4130000/newsid_4132300/4132319. stm

http: //earthquake. usgs. gov/eqcenter/recenteqsww/Maps/region/N_America. php

What is the elastic rebound theory? • It explains how rocks spring back into their original shape after they have been deformed by seismic forces

What is a seismograph? • Instruments that record the vibrations of the Earth during an earthquake • It creates a seismogram

How are earthquakes measured? • The Richter scale of magnitude is a scale used that measures the amplitude (height) of seismic waves

Richter Scale • 1. 0 = 32 x energy • 2. 0 =1024 x • 3. 0 = 32, 000 x • 4. 0 = 1, 000 • 5. 0 = 32, 000 • 6. 0 = 1, 000, 000 • 7. 0 = 32, 000, 000 • 8. 0 = 1, 000, 000 • 9. 0 = 32 x 1013 (320000000)

What is the epicenter? • The position on the Earth’s surface directly above the focus of an earthquake What is the focus? • The point at which stress breaks the friction lock between two plates of the Earth’s crust

What is the relationship between plate tectonics and earthquakes? • Most earthquakes occur along plate boundaries. • Most large earthquakes occur along convergent plate boundaries. • Earthquakes occur deeper and deeper as on plate is being subducted under another plate.

What impact do earthquakes have on humans? • Earthquakes cause buildings and other structures to collapse which causes the most injury and death. • Other dangers include landslides, fires, explosions from broken gas lines, and floods from collapsing dams.

Where would you be most likely to feel a minor earthquake? • Someone on the top floors of a tall building. • Look at the distance the top of the building travels