Faults

Parts of a Fault and Seismic Waves

Sabolscience

Materials needed for class

*Your completed graphic organizer or notes on the types of stress, landforms, and plate boundaries.

*Pen or pencil

*Piece of paper/notebook to draw a diagram.

In this lesson you will learn

• How the three types of stress are related to faults

• The types of faults and related motions of the hanging and foot walls

• Parts of a fault including Fault Line, Focus, Epicenter.

Explore the diagram and the description

Multiple Choice

The line where the rock is broken is called..

• Focus

• Epicenter

• Fault Line

• Earthquake

Multiple Choice

The point inside the earth where the rock starts to break is called the..

• Epicenter

• Focus

• Fault Line

• Earthquake

Multiple Choice

The point on the surface directly above the focus where the seismic waves first reach the surface is called the.

• Focus Point

• Epicenter

• Fault Line

• Total destruction

Seismic Waves

Lets shake things up a bit and learn about the three main types of Seismic Waves.

Primary waves (P)

• The first wave to arrive

• Travels thru solid, liquid, gas

• Push Pull motion

• (P)rimary, (P)ush (P)ull

Secondary Waves (S)

• (S)econd To arrive (S)lower

• (S)ide to (S)ide motion

• Travels thru (S)olids only

Surface (L) Land Waves

• Slowest wave

• Causes the most damage

• Up, Down, and Around motion

• Travels thru solids and liquids

• ("ocean wave" on land)

• (* higher level study both Rayleigh & Love surface waves)

Seismographs

• Tool used to detect movement in the Earth's Crust

• Records the intensity and timing of the arrival of earthquake waved.

• Alone, cannot determine direction earthquake waves came from.

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Finding the Epicenter

• P waves travel at a known fast speed

• S waves travel at a known slower speed

• The distance between the arrival between the P & S waves determines the distance to the epicenter from the seismograph.

Finding the Epicenter

• Apply the arrival times to graph.

• Read the result and you will find the distance to the epicenter.

• Do this with multiple seismograph readings

Finding the Epicenter (cont.)

• Plot the distances from each seismograph on a map

• Where all the circles intersect is your epicenter.

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