Earthquakes - The movement of the ground, caused by waves of energy released as rocks move along...
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Transcript of Earthquakes - The movement of the ground, caused by waves of energy released as rocks move along...
Earthquakes - The movement of the ground, caused by - The movement of the ground, caused by waves of energy released as rocks move waves of energy released as rocks move along faultsalong faults
Fault – a large fracture in rocks, from Fault – a large fracture in rocks, from several meters to many kilometers long, several meters to many kilometers long, where rocks not only crack but also move where rocks not only crack but also move along either side of the breakalong either side of the break
Types of Stresses; tension, compression, & Types of Stresses; tension, compression, & shearshear
Types of Faults; Normal, Reverse, Types of Faults; Normal, Reverse, Strike-SlipStrike-Slip
1. Normal Fault1. Normal Fault – a pull apart fracture – a pull apart fracture in rocks, where rocks that are above in rocks, where rocks that are above the fault surface drop downward in the fault surface drop downward in relation to rocks that are below the relation to rocks that are below the fault surfacefault surface
2. Reverse Fault – a compression fracture in rocks, where rocks that are above the fault surface are forced up over rocks that are below the fault surface
3. Strike-Slip Fault – a break in rocks where rocks on either side of the fault move past each other, instead of above or below each other
Concept of ‘hanging wall’ and ‘footwall’
Footwall: Rock surface ABOVE the fault
Headwall: Rock surface ABOVE the fault
Earthquakes (cont.)
Slow steady pressure produces foldsSlow steady pressure produces folds
Types of folds;Types of folds;anticlines - upward bulging fold (ant hill)anticlines - upward bulging fold (ant hill)
syncline - downward bulging fold (dip)syncline - downward bulging fold (dip)monocline - rock layers on one side of monocline - rock layers on one side of
a fold a fold are higher than the are higher than the other sideother side
Anticline
Syncline
Monocline
Route 23 fold
• Route 23 fold
• Route 23 fold
Stresses Building Stresses Building MountainsMountains
1.1. Folded Mountains – caused by compressionFolded Mountains – caused by compression
2.2. Fault-Block Mountains – caused by tensionFault-Block Mountains – caused by tension
3.3. Plutonic Mountains – result from vertical force Plutonic Mountains – result from vertical force created by rising magmacreated by rising magma
4.4. Volcanic Mountains – result of magma from Volcanic Mountains – result of magma from convergent boundaries reaching Earth’s convergent boundaries reaching Earth’s surfacesurface
Folded MountainsFolded Mountains
Fault-Block Fault-Block MountainsMountains
Plutonic Mountain Plutonic Mountain – Half Dome– Half Dome
Volcanic Mountain Volcanic Mountain – Mt. Fuji– Mt. Fuji
Earthquake EvidenceEarthquake EvidenceCreep – very slow down-slope movement, Creep – very slow down-slope movement,
~1cm/yr., leads to severe cracks in buildings~1cm/yr., leads to severe cracks in buildings
Slide – rapid down-slope movement of soil, rocks Slide – rapid down-slope movement of soil, rocks & debris& debris
Scarps – cliff created by sudden earth movements Scarps – cliff created by sudden earth movements along a fault, identified by a curved scar in the along a fault, identified by a curved scar in the landscapelandscape
Fissure – a long crack in soil or rock, up to many Fissure – a long crack in soil or rock, up to many kilometers in lengthkilometers in length
Tsunami – an ocean wave caused by Tsunami – an ocean wave caused by earthquakes, may reach over 100ft. In heightearthquakes, may reach over 100ft. In height
ScarScarpp
CreepCreep
LandslideLandslide
FissureFissure
Tsunami created by Tsunami created by 9.0 earthquake on 9.0 earthquake on Dec.26, 2004 off the Dec.26, 2004 off the west coast of Sumatra west coast of Sumatra in the Indian Oceanin the Indian Ocean
Chile QuakeChile Quake
Feb. 27, 2010Feb. 27, 2010
Magnitude 8.8 Magnitude 8.8 Offshore Offshore Maule, ChileMaule, Chile
Resultant Resultant TsunamiTsunami
Earthquake DamageEarthquake DamageDepends on;Depends on;
1. location of earthquake1. location of earthquake
2. type of ground under buildings2. type of ground under buildings
3. building design & materials3. building design & materials
4. closeness to coastline in case of tsunami4. closeness to coastline in case of tsunami
The EndThe End
Extra Credit
Find and read a news article on Earthquakes - write a three paragraph essay about the article (at least-5 sentences per paragraph). Please include the article.
Sneak it to me no later than the day of the Earthquake test for credit