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19 Cards in this Set
- Front
- Back
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Richter Scale
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Measures the energy of seismic waves. Measures above the epicenter.
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Mercalli Scale
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Measures the intensity of ground shaking. Number value based on human observations.
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Fault
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Pre-existing geological weakness where 2 plates meet.
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Subduction Zone
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One plate goes underneath another-most common location of earthquakes.
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liquefaction
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Too much water in the ground, becomes liquid and behaves like a fluid because of strong shaking
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Tsunami
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A seismic Seawave
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Epicenter
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The point on the earths surface directly above they hypocenter
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Ring of fire
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Around the pacific. 2/3 of all large earthquakes occur here
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Plate Tectonics
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When stress exceeds the strength of the fault, the rock fractures, this sudden release of energy produces seismic waves.
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Primary hazards of earthquakes
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Primary waves: vibrations caused by compression. Travel through solids liquids and gases
Secondary waves: slower than p-waves. only travel through solids |
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Primary Hazards
-Surface Waves |
Travel along or just below the surface. Surface waves and secondary waves are more destructive than primary waves.
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Secondary Hazards
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Fire, liquefaction, mass movement, and tsunamis
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Earthquake protection
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1) Building Codes
2) HOme and lot design |
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Earthquake adaptation
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1) Evacuation
2) Prepared with plans |
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Forecasting
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1) Earthquake history (probabilistic methods-when its happened in the past, and when it will happen again)
2) Deterministic Methods: Animal behavior, groundwater, etc. |
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Earthquake Land-use planning
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Mapping out seismic activity
Enforcing Building Codes |
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Northridge, CA and Haiti quake
-Similarities and differences |
Northridge: 6.8 magnitude, $20 billion, 72 deaths, 22,000 homeless
Haiti: 7.0 magnitude, $60 billion, 200,000 deaths, 1.5 million homeless |
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Minor Earthquakes
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3-3.9 magnitude
130,000 number of events |
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Great Earthquakes
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8+ magnitude, 1 per year
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