28 terms

# Chapter 2: Earthquakes

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stress
a force that acts on rock to change its shape or volume
tension
stress that stretches rock so that it becomes thinner in the middle
compression
squeezes rock until it folds or breaks
shearing
stress that pushes masses of rock in opposite directions, in a sideways movement
normal fault
a type of fault where the hanging wall slides downward; caused by tension in the crust
hanging wall
the block of rock that forms the upper half of a fault
footwall
The block of rock that forms the lower half of a fault.
reverse fault
a type of fault where the hanging wall slides upward; caused by compression in the crust
strike-slip fault
A type of fault in which ricks on either side move past each other sideways with little up or down motion.
anticline
an upward fold in rock formed by compression of Earth's crust
syncline
a downward fold in rock formed by compression in earth's crust
plateau
a large area of flat land elevated high above sea level
earthquake
the shaking that results from the movement of rock beneath Earth's surface
focus
The point beneath Earth's surface where rock breaks under stress and causes an earthquake
epicenter
the point on Earth's surface directly above an earthquake's focus
P wave
A type of seismic wave that compresses and expands the ground.
surface wave
a type of seismic wave that forms when P waves and S waves reach Earth's surface
Mercalli scale
a scale that rates earthquakes according to their intensity and how much damage they cause at a particular place
magnitude
The measurement of an Earthquake's strength based on seismic waves and movement along faults
Richter scale
a scale that rates an earthquake's magnitude based on the size of its seismic waves
seismograph
a device that records ground movements caused by seismic waves as they move through Earth
moment magnitude scale
a scale that rates earthquakes by estimating the total energy released by an earthquake
seismogram
the record of an earthquake's seismic waves produced by a seismograph
friction
the force that opposes the motion of one surface as it moves across another surface
liquefaction
The process by which an earthquake's violent movement suddenly turns loose soil into liquid mud
aftershock
an earthquake that occurs after a larger earthquake in the same area
tsunami
a large wave produced by an earthquake on the ocean floor
base-isolated buidling
A building mounted on bearings designed to absorb the energy of an earthquake