Seismology. I. Earthquakes Rocks will bend and stretch up to a limit undergoing elastic deformation....
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Transcript of Seismology. I. Earthquakes Rocks will bend and stretch up to a limit undergoing elastic deformation....
![Page 1: Seismology. I. Earthquakes Rocks will bend and stretch up to a limit undergoing elastic deformation. A fault is created when the rock finally breaks.](https://reader035.fdocuments.in/reader035/viewer/2022070415/5697c02c1a28abf838cd9136/html5/thumbnails/1.jpg)
SeismologySeismology
![Page 2: Seismology. I. Earthquakes Rocks will bend and stretch up to a limit undergoing elastic deformation. A fault is created when the rock finally breaks.](https://reader035.fdocuments.in/reader035/viewer/2022070415/5697c02c1a28abf838cd9136/html5/thumbnails/2.jpg)
I. Earthquakes
Rocks will bend and stretch up to a limit undergoing elastic deformation.
A fault is created when the rock finally breaks.
An earthquake is the vibrations produced by the breaking of the rock.
![Page 3: Seismology. I. Earthquakes Rocks will bend and stretch up to a limit undergoing elastic deformation. A fault is created when the rock finally breaks.](https://reader035.fdocuments.in/reader035/viewer/2022070415/5697c02c1a28abf838cd9136/html5/thumbnails/3.jpg)
1. Normal Faults
Tensional forces pull the rock apart.
Rock above the fault surface moves downward compared to the rock below the fault surface.
A. Types of Faults
![Page 4: Seismology. I. Earthquakes Rocks will bend and stretch up to a limit undergoing elastic deformation. A fault is created when the rock finally breaks.](https://reader035.fdocuments.in/reader035/viewer/2022070415/5697c02c1a28abf838cd9136/html5/thumbnails/4.jpg)
2. Reverse Fault
Compression forces squeeze the rock.
Rock above the fault surface moves upward and over the rock below the fault surface.
![Page 5: Seismology. I. Earthquakes Rocks will bend and stretch up to a limit undergoing elastic deformation. A fault is created when the rock finally breaks.](https://reader035.fdocuments.in/reader035/viewer/2022070415/5697c02c1a28abf838cd9136/html5/thumbnails/5.jpg)
3. Strike-Slip Fault
Shear forces tear the rock.
Rocks on either side of the fault are moving past each other without upward or downward movement.
![Page 6: Seismology. I. Earthquakes Rocks will bend and stretch up to a limit undergoing elastic deformation. A fault is created when the rock finally breaks.](https://reader035.fdocuments.in/reader035/viewer/2022070415/5697c02c1a28abf838cd9136/html5/thumbnails/6.jpg)
B. Seismic Waves
Waves generated by earthquakes that travel through the Earth.
1. Origin of Seismic Waves
a.) Focus- the point where the energy is first released.
Below the surface along the fault.
b.) Epicenter- point on the surface of the Earth directly above the focus
![Page 7: Seismology. I. Earthquakes Rocks will bend and stretch up to a limit undergoing elastic deformation. A fault is created when the rock finally breaks.](https://reader035.fdocuments.in/reader035/viewer/2022070415/5697c02c1a28abf838cd9136/html5/thumbnails/7.jpg)
Epicenter
Focus
Fault line
![Page 8: Seismology. I. Earthquakes Rocks will bend and stretch up to a limit undergoing elastic deformation. A fault is created when the rock finally breaks.](https://reader035.fdocuments.in/reader035/viewer/2022070415/5697c02c1a28abf838cd9136/html5/thumbnails/8.jpg)
2. Types of Seismic Waves
a.) Primary Waves (P-Waves)
• Particles in the rock move back and forth in the same direction the wave is traveling.
• Travels trough solids, liquids, & gases
• Fastest seismic waves
![Page 9: Seismology. I. Earthquakes Rocks will bend and stretch up to a limit undergoing elastic deformation. A fault is created when the rock finally breaks.](https://reader035.fdocuments.in/reader035/viewer/2022070415/5697c02c1a28abf838cd9136/html5/thumbnails/9.jpg)
b.) Secondary Waves (S-Waves)
• Particles in the rock move up and down at right angles to the direction of wave travel.
• Travels through solids only.
![Page 10: Seismology. I. Earthquakes Rocks will bend and stretch up to a limit undergoing elastic deformation. A fault is created when the rock finally breaks.](https://reader035.fdocuments.in/reader035/viewer/2022070415/5697c02c1a28abf838cd9136/html5/thumbnails/10.jpg)
c.) Surface Waves (L-Waves)
• Particles in the rock move in a backward, rolling motion and a side-to-side, swaying motion.
•Causes the most damage.
•Originate from the epicenter.
![Page 11: Seismology. I. Earthquakes Rocks will bend and stretch up to a limit undergoing elastic deformation. A fault is created when the rock finally breaks.](https://reader035.fdocuments.in/reader035/viewer/2022070415/5697c02c1a28abf838cd9136/html5/thumbnails/11.jpg)
3. Locating an Epicenter
a.) Seismograph
•Register the waves & record the time that each arrived.
![Page 12: Seismology. I. Earthquakes Rocks will bend and stretch up to a limit undergoing elastic deformation. A fault is created when the rock finally breaks.](https://reader035.fdocuments.in/reader035/viewer/2022070415/5697c02c1a28abf838cd9136/html5/thumbnails/12.jpg)
P WavesS Waves
L Waves
Time between P & S waves = 3 minutes
Time for entire quake = 8 minutes
1 min
Seismogram
![Page 13: Seismology. I. Earthquakes Rocks will bend and stretch up to a limit undergoing elastic deformation. A fault is created when the rock finally breaks.](https://reader035.fdocuments.in/reader035/viewer/2022070415/5697c02c1a28abf838cd9136/html5/thumbnails/13.jpg)
• Data from three separate
stations are required to
locate the epicenter of
an earthquake.
• The epicenter distance
is figured out using the time
difference between the P & S
waves graph.
![Page 14: Seismology. I. Earthquakes Rocks will bend and stretch up to a limit undergoing elastic deformation. A fault is created when the rock finally breaks.](https://reader035.fdocuments.in/reader035/viewer/2022070415/5697c02c1a28abf838cd9136/html5/thumbnails/14.jpg)
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II. Earthquake Activity
A. Magnitude• The amount of energy released in an
earthquake.
•Richter Scale- a numeric scale used to describe the strength (magnitude) of an earthquake.
•Mercalli Scale- scale that describes the amount of damage.
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B. Liquefaction•Wet soil can be strong most of the
time, but the shaking from an earthquake can cause it to act like a liquid.
• This causes soil to sink into the ground and cause things to collapse.
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C. Tsunamis•Under water earthquakes cause the
water to shake forming large waves.
• Seismic sea waves
•Wave crests can reach 30m in height by the time it reaches shore.