earthquake presentation 08 09
DESCRIPTION
TRANSCRIPT
![Page 1: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/1.jpg)
EarthquakesEarthquakesare the vibrationsvibrations caused by sudden
movements of Earth’s rocks.
Forces within the crust cause rocks to
bend or break.
![Page 2: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/2.jpg)
Where do most Earthquakes occur?
12%
88% Ring of Fire
All Others
![Page 3: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/3.jpg)
Most Earthquakes occur:
*along the “Ring of Fire”, a belt which circles the Pacific Ocean
*88% of all earthquakes occur here
![Page 4: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/4.jpg)
Earthquake Belts
along the belts which run through» central Asia» mid-ocean ridges» Mediterranean Sea» Caribbean Sea
Each black dot represents one earthquake over a 10 year period
![Page 5: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/5.jpg)
Earthquake Belts
![Page 6: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/6.jpg)
*due to one or a combination of more than one of three kinds of forces:
1. tension 2. compression 3. shearing
![Page 7: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/7.jpg)
Elastic Rebound
![Page 8: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/8.jpg)
ForcesForces may causerock to:
1. * Fracture » breaks in rock
where no movement has occurred
![Page 9: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/9.jpg)
![Page 10: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/10.jpg)
ForcesForces may causerock to:
2. * Fault » fractures in rock where
movement has occurred» may occur in any direction
along the surface of the break (fault plane)
![Page 11: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/11.jpg)
*Fault Types
»may be one of three types:
1. normal
2. reverse
3. strike-slip (transform)
![Page 12: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/12.jpg)
Normal Fault
![Page 13: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/13.jpg)
Normal Fault
![Page 14: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/14.jpg)
Normal Fault
![Page 15: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/15.jpg)
Normal Fault Structures
![Page 16: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/16.jpg)
![Page 17: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/17.jpg)
Reverse Fault
![Page 18: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/18.jpg)
Reverse Fault
![Page 19: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/19.jpg)
Reverse Fault
![Page 20: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/20.jpg)
![Page 21: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/21.jpg)
Reverse Fault Structures
![Page 22: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/22.jpg)
Strike-slip (Transform) Fault
![Page 23: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/23.jpg)
Strike-slip (Transform) Fault
![Page 24: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/24.jpg)
Strike-Slip Fault
![Page 25: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/25.jpg)
![Page 26: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/26.jpg)
Strike Slip Fault
![Page 27: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/27.jpg)
![Page 28: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/28.jpg)
ForcesForces may cause rock to:
3. *Fold » due to compression» may form one single bend (monocline)» or may form alternating ridges (anticlines)
and troughs (synclines)
![Page 29: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/29.jpg)
monocline
![Page 30: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/30.jpg)
anticlines
![Page 31: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/31.jpg)
synclines
![Page 32: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/32.jpg)
Folded Rocks
anticline
syncline
Where are the oldest rocks exposed at the surface?
![Page 33: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/33.jpg)
Folded Rocks
monocline
rock has a gently dipping bend in the horizontal rock layer.
![Page 34: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/34.jpg)
Seismic Waves
originate from the *focus, the actual point on the fault where movement occurs
affect the point on the earth surface directly above the focus, called the *epicenter
![Page 35: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/35.jpg)
Seismic Waves
may be a *body wave:
1. *P- wave (primary) - rocks particles back and forth, fastest wave, first to arrive
2. *S - wave (secondary) - rocks move forward but vibrate at right angles to the direction of movement, slower than p - wave, arrives later
![Page 36: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/36.jpg)
Seismic Waves
may be a *surface wave:
3. *L- wave (longitudinal) - vibrates the earth’s crust like an ocean wave
is the most destructive
travels very slow compared to P & S – waves
last to reach the seismic station
![Page 37: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/37.jpg)
Seismic Waves
![Page 38: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/38.jpg)
Earthquake DestructionDestruction
Intensityis a measure of the physical damage or geologic change
measured by the
Mercalli Scale
Magnitudeis a measure of the strength of an earthquake recorded by seismographs
measured by the
Richter Scale
![Page 39: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/39.jpg)
![Page 40: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/40.jpg)
How Seismographs Work
![Page 41: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/41.jpg)
Seismograph
![Page 42: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/42.jpg)
Richter Scale
For every increase in 1 on the Richter
Scale….
there is an increase of 32 times the
energy released!
![Page 43: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/43.jpg)
Seismogram
![Page 44: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/44.jpg)
P and S Wave Travel Time Curves
Use the difference in P and S wave arrival times to calculate the distance from the epicenter.
![Page 45: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/45.jpg)
Locating Earthquakes
Station 1Station 1
![Page 46: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/46.jpg)
Locating Earthquakes
Station 2
![Page 47: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/47.jpg)
Locating Earthquakes
Station 3
![Page 48: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/48.jpg)
![Page 49: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/49.jpg)
Locating Earthquakes - Depth
![Page 50: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/50.jpg)
Seismic Waves in the Earth
![Page 51: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/51.jpg)
Seismic Waves in the Earth
![Page 52: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/52.jpg)
Earth’s Interior
P & S waves slow when they hit the upper mantle (asthenosphere)
speed up again when they hit the solid lower mantle
P waves are slowed and deflected when they hit the liquid outer core
![Page 53: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/53.jpg)
Earth’s Interior
S waves do not travel through the liquid outer core
Shadow Zone results between 105o and 140o from an earthquake’s focus
![Page 54: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/54.jpg)
Earth’s Interior
![Page 55: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/55.jpg)
Earth’s Interior
Why is the inner core a solid?
![Page 56: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/56.jpg)
Earth’s Interior
Crust: 3 – 60 miles thick, hard, brittle, continents are thicker than ocean
Mantle: thickest layer, denser than crust, upper mantle is plastic-like (flows under pressure)» Separated from the crust by the Moho or
Mohorovicic Discontinuity» Made of silicon, oxygen, magnesium, iron
![Page 57: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/57.jpg)
Earth’s Interior
Core: innermost layer, made of iron and nickel
» Inner core is solid
» Outer core is liquid
![Page 58: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/58.jpg)
![Page 59: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/59.jpg)
Earthquake Damage
![Page 60: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/60.jpg)
Earthquake Damage
![Page 61: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/61.jpg)
Earthquake Damage
![Page 62: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/62.jpg)
Earthquake Damage
![Page 63: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/63.jpg)
Earthquake Damage
![Page 64: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/64.jpg)
Earthquake Damage
![Page 65: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/65.jpg)
Earthquake Damage
![Page 66: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/66.jpg)
Earthquake Damage
![Page 67: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/67.jpg)
Earthquake Damage
![Page 68: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/68.jpg)
Earthquake Damage
![Page 69: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/69.jpg)
Earthquake Damage
![Page 70: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/70.jpg)
Earthquake Safety
Outdoors – move to an open area» Stay away from chimneys, buildings, trees» Stay away from beaches
Indoors » move away from windows, large objects» Seek shelter under table, desk, doorway, basement stairs» Turn off electricity, water, gas if possible
![Page 71: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/71.jpg)
Tsunamis
Probably Caused by Submarine Landslides
Travel about 400 m.p.h.
Pass Unnoticed at Sea, Cause Damage on Shore
![Page 72: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/72.jpg)
Tsunamis
Whether or Not Damage Occurs Depends on: » Direction of Travel » Harbor Shape » Bottom topography» Tide & Weather
![Page 73: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/73.jpg)
Tsunamis
![Page 74: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/74.jpg)
Satellite images from NASA show the destruction caused by a tsunami to the Indonesian province of Aceh. The left photo shows the town of Lhoknga before the tsunami hit on Dec. 24, 2004.
![Page 75: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/75.jpg)
Tsunamis
![Page 76: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/76.jpg)
Tsunamis
![Page 77: Earthquake Presentation 08 09](https://reader033.vdocuments.us/reader033/viewer/2022061121/546f4162af7959330b8b69bf/html5/thumbnails/77.jpg)
Tsunamis