Section 8.1 What is an earthquake

focus

The point beneath Earth where an earthquake originates

true

True or False: it was not until the 1906 San Francisco earthquake was studied that the actual cause of earthquakes was understood

fault

a fracture in Earth along which movement has occurred

aftershock

a small earthquake that follows the main earthquake

about 100

how many major earthquakes take place each year

fault creep

slow gradual movement of a fault

elastic rebound

tendency for deformed rock along a fault to spring back to its original shape after an earthquake

elastic rebound

the ______________________________ hypothesis states that when rocks are deformed they bend and then break releasing stored energy

epicenter

the location on Earth's surface directly above the focus, or origin, of an earthquake

earthquake

the vibration of Earth produced by the rapid release of energy

true

true or false: most earthquakes occur along existing faults

seismic waves

vibrations that travel through Earth carrying the energy released during an earthquake