QUIZ 10/211. What are Earthquakes? 2. _____ is the deformation of a

material caused by stress. 3. Describe tension stress. 4. Faulting causes rock to _________ .

Answers 1. Vibrations of the earth’s crust caused by a

sudden release of energy

2. Strain

3. pulls apart

4. Break

QUIZ 10/22 1. Define fault. 2. Which type of fault is a result of tension stress

causing horizontal & vertical movement.3. Which type of fault is a result of compression

stress causing horizontal & vertical movement? 4. Which type of fault is a result of shear stress

causing horizontal movement? BONUS:What type of fault is associated with divergent plates?

Answers 1.Fault = any fracture or system of

fractures along which the Earth moves

2. Normal Fault 3. Reverse Fault 4. Strike Slip Fault 5. Normal Fault

Seismic Waves Vibrations of the ground during an

earthquake are called seismic waves

Vibrations (earthquakes) occur as rock elastically returns to its original position. Feels like

shaking or trembling

Every EQ generates three types of seismic waves

1.Primary2.Secondary

3.Surface

Primary Waves• P- waves • Fast waves• Travel through solids, liquids, or

gases• Compressional movement,

squeeze & push rocks in the direction which the waves are traveling

Secondary waves • S-waves • Slower than P waves• Travel through solids only• Shear movement of rocks at

right angles in the direction of the waves

Body Waves Both P- waves and S-waves pass

through Earth’s interior, because of this they are referred to as BODY

WAVES

Surface Waves

Slowest types of wave Travels only along the Earth’s

surface Up & down and side-to-side

movement Cause the most ground movement

and take the longest time to pass Usually causes the most

destruction

Rayleigh waves

ground rolls; ground moves

up & down similar to

water waves

Love wavesshear waves

cause the ground to move

horizontally from side to

side

Body waves

(P and S) travel inside Earth.

Surface waves travel along Earth’s surface.

Body Waves and Surface Waves

The Focus and Epicenter of an EQ• The point below

the Earth’s surface where faulting begins & waves originate is called the focus

• The point directly above the focus on the surface is the epicenter

HOMEWORK

• READ TEXT p 532-534• Quiz???

ANY QUESTIONS?