SEISMIC WAVES
are the waves of energy caused by the sudden breaking of rock within the earth or an explosion.
Seismographs or Seismometer is an instrument used to detect and record earthquakes.
Types of Seismic Waves
BODY WAVES
P WAVES
arrive before the surface waves emitted by an earthquake.
These waves are of a higher frequency than surface waves.
Traveling through the interior of the earth.
Can move through solid rock and fluids, like water or the liquid layers of the earth.
It pushes and pulls the rock it moves through just like sound waves push and pull the air.
This is the fastest kind of seismic wave, and, consequently, the first to arrive at a seismic station.
S WAVES
also known as compressional waves
is the second wave you feel in an earthquake.
an S wave is slower than a P wave and can only move through solid rock, not through any liquid medium.
it is this property of S waves that led seismologists to conclude that the Earth's outer core is a liquid.
S waves move rock particles up and down, or side-to-side--perpendicular to the direction that the wave is traveling in (the direction of wave propagation). Click here to see a S wave in action.
traveling only through the crust.
are of a lower frequency than body waves, and are easily distinguished on a seismogram as a result.
waves that are almost entirely responsible for the damage and destruction associated with earthquakes.
This damage and the strength of the surface waves are reduced in deeper earthquakes.
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LOVE WAVES
RAYLEIGH WAVES
It's the fastest surface wave and moves the ground from side-to-side. confined to the surface of the crust.
waves produce entirely horizontal motion.Click here to see a Love wave in action.
named after A.E.H. Love, a British mathematician who worked out the mathematical model for this kind of wave in 1911.
named for John William Strutt, Lord Rayleigh, who mathematically predicted the existence of this kind of wave in 1885.
A 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.
Most of the shaking felt from an earthquake is due to the Rayleigh wave, which can be much larger than the other waves.