Earthquakes and Landscapes Flashcards
Understand what causes earthquakes and how land forms are made by them.
What causes earthquakes?
Stress is applied to a body of rock,
Rocks deform while storing energy,
Eventually stress becomes greater than the strength of the rock and the rock breaks
Energy from earthquakes is in the form of
Seismic waves
Define focus:
The location where earthquakes originate, the initial fracture
Define epicenter:
The point directly above the focus on the Earth’s surface.
Define Magnitude:
Measures the amount of energy released
Define intensity:
Measures the amount of shaking that has occurred,
Determined by humans and property damage
What is attenuation?
The amount of shaking decreases with increasing distance from the focus
What is amplification?
Amplification occurs when the amount of shaking increases with distance because of loose sediment.
What does the Richter scale measure?
Measures amplitude or wave displacement, on a logarithmic scale.
Mercalli’s scale is based on:
the amount of damage sustained.
What are the four factors that determine structural damage?
- Magnitude of the earthquake
- Duration of the vibrations
- Nature of the material upon which the structure rests
- The design of the structure
Define Liquefaction:
saturation of ground material turning into a fluid
What is a Tsunami?
Giant sea wave that is produced by a sudden displacement of ocean water.
Damage is not proportional to magnitude, Damage is proportional to _____?
population density
example:
Alaska (1964); 9.2M resulted in 131 deaths
Haiti (2010); 7.0M resulted in 300,000 deaths
Majority of earthquakes occur along ______.
the plate boundaries
