1 / 10

Measuring Earthquakes Chapter 5.2-5.3

Measuring Earthquakes Chapter 5.2-5.3. Where do Earthquakes begin? What is the difference between the focus and epicenter?. Earthquakes always begin in rock below the surface, usually within 100 km of Earth’s surface.

gefen
Télécharger la présentation

Measuring Earthquakes Chapter 5.2-5.3

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. Measuring EarthquakesChapter 5.2-5.3

  2. Where do Earthquakes begin? What is the difference between the focus and epicenter? Earthquakes always begin in rock below the surface, usually within 100 km of Earth’s surface. Focus: The point where rock that is under stress breaks, triggering an earthquake. Epicenter: The point on the surface directly above the focus. Epicenter/focus animation

  3. What are seismic waves? Where are the seismic waves the strongest? Seismic Waves: vibrations that travel in a ripple through Earth, carrying the energy released during an earthquake. .

  4. Three Categories of Seismic Waves P Waves (Primary Waves) - First to arrive at a seismograph - compress and expand ground

  5. Three Categories of Seismic Waves (cont.) 2) S Waves (Secondary Waves) - Vibrate from side to side AND up and down - 2nd to arrive at seismograph Animation of P and S waves Video on P and S Waves

  6. Three Categories of Seismic Waves (cont.) 3) Surface Waves. Produce the most severe ground movements.

  7. How do we detect seismic waves? How do we measure earthquakes? Seismograph: a machine that records the ground movements caused by seismic waves as they move through the earth. seismograph animation Magnitude: measurement of earthquake strength based on seismic waves and movement along faults.

  8. 3 types of rating scales (continued) Mercalli Scale – Not a precise measurement The same earthquake can have different ratings

  9. Which scale do we use today? 2) Richter Scale Rates size of seismic waves with a mechanical seismograph Accurate for small, nearby earthquakes Not accurate for large or distant earthquakes. 3) Moment Magnitude Scale Estimates total energy released by earthquake Used to accurately rate all earthquakes of all sizes, near or far What we currently use

  10. How many seismographs do you need to determine an epicenter Locating the epicenter: You need 3 seismographs to determine an epicenter. Locating an Epicenter Video

More Related