Investigation 2 Facts The Interior of the Earth. Fault A break in Earth ’ s crust where rock on one side moves in relation to rock on the other side.

Investigation 2 Facts

The Interior of the Earth

FaultA break in Earth’s crust where rock on one side moves in relation to rock on the other side.

Seismic waveA vibration in Earth’s crust, caused by the release of energy at a fault.

Point of originsFocus

The point inside Earth where a seismic wave begins.

EpicenterThe point of the

Earth surface directly above the focus.

Measuring MagnitudeRichter Scale

Charles Richter developed a scale that uses the size of waves to determine the magnitude of an earthquake.

Seismograph Any of various instruments for measuring and recording the vibrations of earthquakes.

SeismologistScientist that studies seismic waves.

TsunamiAn unusually large sea wave produced by a seaquake or undersea volcanic eruption.

Types of Seismic Waves Body Waves

Compressional Wave (P-Wave) Primary

Shear Wave (S-Wave) Secondary

Surface WavesRayleigh Wave

named for John William Strutt, Lord Rayleigh. He mathematically predicted this kind of wave in 1885 Love Wave

named after A.E.H. Love, a British mathematician who discovered it in 1911.

Investigation 2 VocabularySeismographShadow zonePhysical modelConceptual modelMathematical modelNumerical Model

Average wave speedCompressional wave (p-wave)Shear wave (s-wave)Seismic waveBoundaryRefractionRichter scaleMagnitude

Body WavesCompressional

WaveEnergy is compressed or squeezed together then released in a straight pathway.

Able to flow through solids, liquids, and gases

Shear WaveThe second wave you feel in an earthquake.

An S wave is slower than a P wave and can only move through solid rock.

Surface WavesRayleigh WaveA Rayleigh wave rolls along the ground just like a wave rolls across a lake or an ocean. Because it rolls, it moves the ground up and down, and side-to-side in the same direction that the wave is moving.

Love WaveIt's the fastest surface wave and moves the ground from side-to-side.

http://www.geo.mtu.edu/UPSeis/waves.html

RefractionWave refraction: When a set of waves cross a boundary (change of material in the Earth’s surface) causing it to change speed and direction.

Average Wave SpeedThe average speed a wave travels in a matter of seconds.Ave. wave speed= distance (cm)

time (s)

Seismograph Records the magnitude of each wave as a passes a seismograph station.