1 / 14

CHAPTER 7 EARTHQUAKES

CHAPTER 7 EARTHQUAKES. 7.1 Notes What are earthquakes?. earthquakes - movements or shaking of the ground when rock (plates) move suddenly and release energy. aftershock – a release in energy after an earthquake. Where do most earthquakes happen?. On plate boundaries (page 232).

bertham
Download Presentation

CHAPTER 7 EARTHQUAKES

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CHAPTER 7EARTHQUAKES

  2. 7.1 NotesWhat are earthquakes? • earthquakes - movements or shaking of the ground when rock (plates) move suddenly and release energy. • aftershock – a release in energy after an earthquake

  3. Where do most earthquakes happen? On plate boundaries (page 232)

  4. What causes earthquakes? • Movement of the tectonic plates • When the plates break at a fault located at a boundary

  5. How do we know there are different layers of the Earth? • Because of seismic waves from earthquakes • Seismic waves travel through solids faster than liquids • Seismic waves change direction when they change the material they are going through (from a solid to a liquid) • elastic rebound – the sudden return of deformed rock to its normal undeformed shape. (i.e. rubber band)

  6. 7.1 Notes • seismic waves – waves of energy that travel through and on the Earth • 2 types of seismic bodywaves: • P-waves (primary waves) – the fastest seismic waves that travel through solids, liquids, and gases • (the P-waves move like a slinky) • S-waves (secondary waves) – the second fastest seismic waves that travel through solids • (the S-waves move like a snake) • 1 type of seismic surfacewaves : • L-waves (land & last waves) – the slowest and most destructive seismic waves that travel only on the surface/land • (the L-waves move in big slow circles)

  7. 7.2 NotesEarthquake Measurements • epicenter – the point on the Earth’s surface directly above the earthquake’s starting point • focus – the point inside the Earth where an earthquake begins

  8. 7.2 Notes • seismograph – an instrument at or near the surface of the Earth that record seismic waves (machine) • seismogram – is a tracing of earthquake motion created by a seismograph (paper)

  9. How do you find an epicenter? • You need to find the S-P time difference and that is the distance from the seismograph to the epicenter. • P-wave time minus the S-wave time • Draw a circle around the seismograph location. • Do this three times because you need three seismograph stations to find an epicenter. • Where all three circles intersect is where the epicenter is located.

  10. To find an epicenter you need three seismograph stations. Where are three radiui interest is where the epicenter is located.

  11. 7.2 Notes • The Richter scale measures the magnitude. • magnitude – the strength of an earthquake • The Mercalli scale measures the intensity. • intensity – the amount of damage caused by an earthquake

  12. How do we measure an earthquake’s intensity – the amount of damage caused by an earthquake? • Magnitude – how strong it is (measured by the Richter scale) • Population – the more people are around when it happens the more dangerous it is • How much money it costs to repair the damages – the more money it costs the more damage was done • Location – Where did it happen?

  13. How does the magnitude compare to the other factors that measure the intensity?

  14. 7.3 • tsunami – a giant ocean wave that forms after a volcanic eruption, an earthquake in the ocean, a landslide, or a big asteroid hitting the ocean. • What is the major problem with a tsunami? • Coastal flooding. Homes are destroyed due to the water damage.

More Related