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Earthquakes

NARAYANA E-TECHNO SCHOOL

DHARMAVARAMS.DHEERAJ

E-CHAMPS STUDENT

PRESENTED BY

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Defintion: An earthquake (also known as a quake, tremor or

temblor) is the result of a sudden release of energy

in the earths crust that creates seismic waves.

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What is an earthquake?

Used to describe both sudden slip on a fault,

and the resulting ground shaking and radiated

seismic energy caused by the slip

Caused by volcanic or magmatic activity,

Caused by other sudden stress changes in the

earth.

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Three Types of Faults

Strike-SlipThrust

Normal

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What causes earthquakes?

Tectonic plates move past each other causing

stress. Stress causes the rock to deform

Plastic deformation does not cause earthquakes

Elastic deformation rock stretches then reaches

a breaking point, releasing energy.

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Elastic Rebound deformed rock goes

back to its original shape

http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM

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Focus point inside the Earth where an

earthquake begins

Epicenterpoint on Earths surface above focus

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How Seismographs Work

http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM

the pendulum remains

fixed as the ground

moves beneath it

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Typical Seismogram

http://isu.indstate.edu/jspeer/Earth&Sky/EarthCh11.ppt

http://isu.indstate.edu/jspeer/Earth&Sky/EarthCh11.ppthttp://isu.indstate.edu/jspeer/Earth&Sky/EarthCh11.ppt

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Primary Waves (P Waves)

A type of seismic wave that compressesand expands the ground

The first wave to arrive at an

earthquakehttp://daphne.meccahosting.com/~a0000e89/insideearth2.htm

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Secondary Waves (S Waves)

A type of seismic wave that moves theground up and down or side to side

http://daphne.meccahosting.com/~a0000e89/insideearth2.htm

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Comparing Seismic Waves

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Surface Waves

Move along the Earths surface

Produces motion in the upper crust

Motion can be up and down

Motion can be around

Motion can be back and forth

Travel more slowly than S and P waves

More destructive

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How do scientists calculate how far a location isfrom the epicenter of an earthquake?

Scientists calculate the differencebetween arrival times of the P wavesand S waves

The further away an earthquake is, thegreater the time between the arrival of

the P waves and the S waves

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Locating Earthquakes

http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM

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Locating Earthquakes

http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM

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Locating Earthquakes

http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM

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How are Earthquakes Measured?

Richter Scale

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How are Earthquakes Measured?

Mercalli Intensity Scale

Click Link for Interactive Demo

http://elearning.niu.edu/simulations/images/S_portfolio/Mercalli/Mercalli_Scale.swf

http://elearning.niu.edu/simulations/images/S_portfolio/Mercalli/Mercalli_Scale.swfhttp://elearning.niu.edu/simulations/images/S_portfolio/Mercalli/Mercalli_Scale.swf

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Earthquake Waves & Earths Interior

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Seismic

Waves inthe Earth

http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM

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Conclusion:

To help prevent a roof from collapsing,

builders make the roof out of light-weight

materials. Outdoor walls are made with

stronger and more reinforced materials such

as steel or reinforced concrete. During an

earthquake flexible windows may help hold

the windows together so they dont break.

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