Earthquake Notes

8-3.8 Explain how earthquakes result from forces inside Earth.

What is an Earthquake?

The definition of an earthquake is… ______that causethe breaking of rocks.

These vibrations move in all directions through the earth. They begin at a point along a ______.

  • If the ______or stress becomes too great, the rock breaks at a weak point along the fault and ______is released.

PARTS OF AN EARTHQUAKE

  • The energy spreads outward in all directions as vibrationscalled ______.
  • The ______of the earthquake is the point in the crust, or mantle, where energy is ______.
  • The ______is the point on Earth’s surface directly above the ______; energy that reaches the surfaceis ______at this point.

RECAP (Take a minute to fill in the blank)

______: is located right above the focus and has the greatest amount of energy

______: releases the energy (seismic waves)

______: a break in the Earth’s Crust (is where an earthquake takes place)

______: is the energy that is being sent out from the focus

Use the words above to Label the Following parts of the earthquake.

8-3.2Explain how scientists use seismic waves – primary, secondary, and surface waves – and Earth’s magnetic fields to determine the internal structure of Earth.

Seismic Waves: There are 3 types of seismic waves: ______

•_SEISMIC WAVES___are waves generated by an earthquake that travel through the Earth. These waves can cause the ground to moveforward, backward, up, down, and even to ripple. Seismic Waves are generated at the ______time but move in different ways, and at different speeds.

Seismic Waves

Scientists use the principle that the ______of a seismic wave depends on the material it travels through. How does scientist know or study the Earth’s Core?Because of the behavior of these different waves, scientists have indirect evidence for the solid inner core and liquid outer core of Earth because ______don’t travel through the outer core because it’s a ______. Also because earthquake waves travel faster through the mantle than through the crust, scientists know that the mantle is denser than the crust.

Types of Seismic Waves / Movement/Description / Travels Through / Illustration
Primary Waves
(P Waves) /
  • ______Wave to Move out from the earthquake focus, the point where the energy is released
  • Travel the ______ of the three waves
  • Push and pull rock creating a back-and-forth motion in the direction the wave is moving
(known as longitudinal or compressional waves) /
  • Move through solid and liquid layers of Earth (therefore it can move through ______layers)
/
Secondary Waves
(S Waves) /
  • ______wave to Move out from the earthquake focus
  • Move ______than primary waves
  • Move at ______ to primary waves causing rocks to move up and down and side to side (known as ______wave: perpendicular to the wave motion)
/
  • Can only move through ______rock therefore it CAN NOT TRAVEL THROUGH THE ______because it is a ______. IT ______AT THE OUTER CORE.
/
Surface Waves /
  • Form when P and S waves reach the surface
  • ______
  • Can cause the ground to shake making rock sway from side to side and roll like an ocean wave
/
  • Move through solid and liquid layers of Earth (therefore it can move through ______layers)
/

8-3.3 Infer an earthquake’s epicenter from seismographic data.

  • The energy spreads outward in all directions as vibrations called ______.
  • Seismic waves can be measured and recorded by a ______.
  • The vibration record, called a ______, looks like jagged lines on paper. Measuring the time between the arrival of the P and S waves determines the ______between the recording seismograph and the earthquake epicenter.

/ SEISMOGRAPH /
SEISMOGRAM

How to find the S-P INTERVALS

  • To find the S-P intervals, you have to ______the ______Wave from the ______Wave.
  • Measuring the time between the arrival of the P and S waves determines the distance between the recording seismograph and the earthquake epicenter.

Find the S-P interval: Show your steps.

/
What are the S-P Intervals? ______ /
What are the S-P Intervals? ______
  • ______identifies the ______of an earthquake. The location of an earthquake’s epicenter is found by plotting ______ on a map from the records of three seismograph stations and finding the point where the three circles ______. Note where the 3 circles meet is where the ______is located.

MONDAY HW

Answer the Following Questions. (8-3.8)

1. The order of seismic waves leaving from the focus is ______.

  1. P-wave, S-wave, Surface Wave
  2. P-wave, Surface Wave, S-wave
  3. S-wave, Surface Wave, P-wave
  4. Surface Wave, P-wave, S-wave

2. How do you identify the process triangulation?

3. The process triangulation is used to find what?

4. What is the difference between a seismograph and a seismogram?

5. Explain 3 differences between the P and S waves.

TUESDAY HW

1. Where is the greatest amount of energy being released on the surface?

2. The energy of an earthquake is called?

3. Earthquakes happen along what?

4. Where is energy being released during an earthquake?

5. What is the most destructive seismic wave and when does it occurs?

WEDNESDAY HW

STUDY FOR QUIZ