seismology

The study of earthquakes

deformation

The bending, tilting, and breaking of the Earth's crust; the change in the shape of rock in response to stress

Seismic wave

A wave of energy that travels through the Earth, away from an earthquake in all directions

P wave ( pressure wave/ primary wave)

A seismic wave that causes particles of rock to move in a back-and-forth direction

S wave (shear wave/secondary wave)

a seismic wave that causes particles of rock to move in a side-to-side direction

earthquake

Shaking of the ground

seismologists

Scientists who study earthquakes

Tectonic plates

Giant pieces of the Earth's thin, outermost layer that move around on top of a layer of plastic rock

fault

A break in the Earth's crust along which blocks of the crust slide relative to one another

Body waves

Waves that travel through the Earth's interior

Surface waves

Waves that travel along the Earth's surface

seismograph

An instrument that records vibrations in the ground and determines the location and strength of an earthquake

seismogram

A tracing of earthquake motion that is created by a seismograph

epicenter

The point on Earth's surface directly above an earthquake's starting point, or focus

focus

The point along a fault at which the first motion of an earthquake occurs

S-P time method

Method in which scientists collect several seismograms of the same earthquake graph them, match them up, and find the earthquake's epicenter

Richter magnitude scale (Richter scale)

1-10 scale used to measure an earthquake's magnitude or strength

magnitude

A measure of the strength of an earthquake

intensity

A measure of the degree to which an earthquake is felt by the people and the amount of damage caused by the earthquake

Earthquake hazard

A measurement of how likely an area is to have damaging earthquakes in the future

may 22, 1960

magnitude 9.5

Approximately 1,655 killed, 3,000 injured, 2,000,000 homeless, and $550 million damage in southern Chile;