high or low vibration in the ground that results in movement along breaks in the earth's surface

The tectonics plates also push and pull on rocks along the fault

Earthquakes the occur on the convergent boundaries are the most dangerous

Shallow earthquakes are common where plates separate along a divergent plate boundary

Avfaults is a break in earths lithosphere where one block if rock moves towards, away, or past other

Epicenter is the location on earth's surface directly above the earthquake's focus

These waves originate where rocks first move along the fault, at a location inside Earth called the focus

Primary waves cause particles in the ground to move in a push-pull motion similar to a coiled spring

Secondary waves cause particles to move up and down at right angles relative to the direction the wave moves

Surface waves cause particles in the ground to move up and down in a rolling motion

Scientists that study earthquakes are called seismologists

A seismometer measures and records ground motion and can be used to determine the distance seismic waves travel

The richter magnitude scale uses the amount of ground motion at a given distance from an earthquake to determine magnitude

The richter scale begins at zero but their is no upper limit to the scale

The seismologists use the movement magnitude scale the measure the total amount of energy released by the earthquake

Normale fault blocks pull apart, rockabove fault moves down