Earthquakes Pages C14-17

What is an Earthquake? A vibration, or shaking of earth’s crust During an earthquake, rock may move up and down, side to side, or both

What is a Fault? A break in the crust along which rock moves Earthquakes occur along fault lines

Why is Focus Important? This is the underground spot where the movement first happened The epicenter is the surface point right above the focus. This will be the place with the most violent movement and the most destruction.

How are Earthquakes Monitored? A seismograph records earthquake waves. A pen attached to the machine moves as the quake occurs, charting the strength of the movements.

Seismograph At Work

How are Earthquakes Measured? Scale of numbers 1-9 used to measure the energy created by a quake is called the Richter Scale Scale of Roman numerals I to XII used to measure earthquake energy is called the Mercalli scale.

Charles Richter

Review What is an earthquake? Shaking or vibration of Earth’s crust What is a fault? A break in the crust, along which rocks move

What happens at an earthquake’s focus? The first movement occurs Where is the epicenter located? On the surface directly above the focus

The most violent movement/damage occurs at which point? Epicenter