A shaking of Earth's crust caused by a release of energey .
What is the cause of most major earthquakes?
- The strain that builds up along faults at or near boundaries between lithospheric plates.
What is a fault?
A break in the lithosphere along which movement has occured.
What is the focus?
The point at which the first movement occurs during an earthquake and the point at which rock beginsto move or break. It is where the earthquake originates and is usually many km beneath the surface.
What is the epicenter?
The point on earth's surface directly above the focus.
WHat are body waves?
Waves that travel from the focus of an eartquake through Earth
What is a P wave?
The body waves known as compressional waves, primary waves, squeeze and stretch rock materials as they pass through Earth. Can travel through any material.
What is an S wave?
The body waves called shear waves, secondary waves cause particles of rock material to move right angles to the dircetion in which the waves are traveling. Can travel through solid material, but not through liquids or gases.
What are surface waves?
Earthquake waves that travel along earth's surface. Produced when Pwaves and S waves reach Earth's surface.
What are Love waves?
A type of surface wave. Cause particles of materials to move from side to side, in a direction perpendicular to the waves' direction of travel.
What are Raleigh waves?
A type of surface wave. Travel more slowly than Love waves and cause particles of material to move in elliptical patterns.
What is a seismograph?
An instrument that detects and records waves produced by earthquakes that may have originated hundreds of km away
What is a seismogram?
A record sheet that is placed on a drum attached to the base.
What is magnitude?
A measure of the amount of energy in an earthquake, (strength).
What is the Richter scale?
A scale that determines an earthquakes magnitude
What is liquefaction?
Occurs when loose soil temporarily takes on some of the properties of liquid
What is an afterschock?
Smaller earthquakes that follow a large earthquake.
What is a tsunamis?
Huge ocean waves caused by underwater earthquakes and landslides.Can travel ver quickly across large expanses of water.
What are seismic gaps?
An area along a seismically active fault where no earthquake activity has occurred over a long period of time.
What is a shadow zone?
A wide belt around the side of Earth opposite the focus of the earthquake.
What is Moho?
Boundary where the dense rock of mantle meets the less dense rock of the crust.
What is the transition zone?
It separates the upper mantle from the denser lower mantle.
What is stress?
Force per unit area acting on a material.
What is strain?
Deformation of materials in response to forces acting upon them.
What is a reverse fault?
Fractures that form as a result of horizontal compression ----> <------
What are normal faults?
Fractures caused by horizontal tension. <---- ----->