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Seismic WavesMuhammad Kamran

Kamran.be12@igis.nust.edu.pk

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What are seismic waves?

Full of energy

Very fast moving (Speed in km/s)

Breaking ofrocks

EarthquakeSeismicWaves

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History

Chinese attempted 2000 years ago to

determine support attached to the ground.

Ancient people superstitions.

Seismology: The study of seismic waves is

called as seismology.

and it isYOUNG SCIENCE >> 150 yearsapprox.

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Some terminologies

Focus:The location within the earth

where rocks damage take place is called

focus of the earthquake. Seismic waves

first originate here.

Epicenter:The point on surface of earth

right above the focus is known as

epicenter.

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Types of Seismic Waves

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P-waves

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S-Waves

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Love and Rayleigh waves

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Earthquake - EpicenterLocation:

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Earthquake Depth ofFocus:

Category Depth kms

Shallow focus 0-70

Intermediate 70-350

Deep 350-670

Estimated by doing analysis on seismogram,

It is calculated by different in velocity of p and s

waves and arrival at recording station.

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Measuring size ofEarthquake

Modified Mercalli scale:

Richter scale:

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Effect of Seismic Waves(Earthquakes):

Vibration and damage of buildings.

Life losses and injuries due to hitting of falling debris

from buildings during earthquake.

Liquefaction which is flowing of water saturated soil aftergetting shake due to earthquake.

Probability of fire after earthquake due to broken gas

pipes and electric lines.

Landslides triggered by shaking of ground. Tsunamis i.e. high rising water waves due to disturbing

of water equilibrium in case of shaking.

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T

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