1 / 8

Chapter 6 - Earthquakes

Chapter 6 - Earthquakes. What is an earthquake? An earthquake is the vibration or movement of the earth produced by the rapid release of energy in wave form usually along a fault line. These fault lines are typically found at plate boundaries.

merced
Télécharger la présentation

Chapter 6 - 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 6 - Earthquakes • What is an earthquake? An earthquake is the vibration or movement of the earth produced by the rapid release of energy in wave form usually along a fault line. • These fault lines are typically found at plate boundaries. • The center of an earthquake is called the focus, while the place directly above the focus at the surface is called the epicenter.

  2. Earthquakes: It’s Not My Fault! • At fault lines there is constant motion as one plate slides or moves against another. • Since rocks exhibit elastic rebound, this energy can build up a the rocks compress. • Eventually, the energy is released causing earthquakes while the rocks snaps back much like an elastic band. • The San Andreas Fault is probably the most studied fault.

  3. Fault movement • Three types: • Fault creep – low gradual displacement, hardly noticeable. • Stick-slip – alternating periods of sticking followed by slippage causing rapid release of energy. • Fault scarp – vertical causing cliff formation

  4. Absolutely Shocking! • The adjustments of the bedrock as it settles after an earthquake often results in aftershocks. These are usually weaker than the original quake. • Small minor quakes can precede a major quake and they are called foreshocks.

  5. Seismo Stuff • Seismology – the study of earthquake waves. • Seismologists – the people who do the studying. • Seismographs – instrument used to record quake waves. • Seismograms – the actual print out from a seismograph. See page 160

  6. You Don’t Want to Catch These Waves Dude! • There are two main groups of seismic waves: • Surface waves – these travel along the outer surface of the lithosphere. • Body waves – These are divided into two groups: A. Primary or P-waves B. Secondary or S-waves

  7. P-Waves • P-waves are push-pull waves that cause the volume of the rock to temporarily change. They act on the rock in the same direction the wave is traveling. • They travel the fastest and they travel through all materials. • They are recorded first by seismographs.

  8. S-Waves • S-waves travel slower than p-waves and they act on the rock perpendicular to the direction the wave is traveling. • They temporarily change the shape of the materials they travel through. However, fluids like liquids and gases do not respond to this type of change. Therefore, s-waves can not travel through them.

More Related