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Earthquakes

Terms in this set (38)

Reverse fault
Fault that forms when compression causes the hanging wall to move over the foot wall
Hanging wall
Block of rock that lies above a fault
Syncline
Layers of rock that bend producing a downward fold
Strike slip
Shearing creates ________ fault, like the San Andreas in California
Tension
The stress force that pulls on the crust where two plates are moving apart is called _______
Surface waves
The seismic waves that travel along earths surface and produce the most severe ground movements are _______
Seismic waves
Vibrations that move through the ground carrying the energy released during an earthquake are _______
Richter scale
Which scale measures the strength of an earthquake based on seismic waves and movement along a fault?
Secondary waves
Earthquake waves that vibrate from side to side and up and down only through solids are ________
Syncline
A valley that dips between two parallel ranges of hills was formed by a downward fold in rock called _______
Faults
Geologists determine earthquake risk by locating where _____are active.
Why can't geologists predict exactly where & when earthquakes will occur?
The can't be sure when and where will be released along a fault
Compression
Squeezing together of rocks by stress
Moment magnitude scale
Scale that rates earthquakes by estimating the total energy released by he earthquake
P wave
Type of earthquake wave can travel through both liquids and solids
Tiltmeter
Type of fault monitoring device most like a carpenters level
What direction do seismic waves carry the energy of an earthquake?
Away from the focus
What happens when friction between opposite sides of a fault is high?
The fault locks and stress builds up until an earthquake occurs
Plateau
A large area of flat land elevated high above sea level
Creepmeter
A device that uses wire stretched across a fault.
Best way to protect yourself in an earthquake?
Drop, cover and hold
GPS satellite
Monitors both vertical and horizontal movements along a fault
Why is risk of earthquakes high along the pacific coast of US?
That's where pacific and North American plates meet
Stress
Force that acts on rock to change its shape or volume
Up or down motion
In a a strike slip fault the rocks on either side of the fault slip past each other sideways with little _______
P waves
The types of seismic waves that arrive at the surface first and move by compression and expanding the ground
Slower
Compared to P waves and S waves surface waves move ______
Mercalli scale
Scale most likely used to tell how much earthquake damage was done to homes & other buildings
What does a seismograph record?
Ground movement caused by seismic waves
Aftershock
Can cause damage days or months after. Large earthquake
Tsunami
A large wave produced by an earthquake on the ocean floor
Base isolated building
A building designed to reduce the amount of energy that reaches the building during an earthquake
Shearing
Stress that pushes a mass of rock in two opposite directions
Footwall
In a normal fault, the part of the fault that lies below the other part is called the ______
Compression
Which type of stress force produces reverse faults?
Fault block mountain
Land between two normal faults moves upward to form a _____
Anticline
A fold in rock that bends upward into an arch
Focus
Point beneath Earths surface where rock breaks under stress and triggers an earthquake
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