THE EARTH
INTERNAL STRUCTURE OF EARTH
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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P waves
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S waves
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L waves
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None of these
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Detailed explanation-1: -The answer is compressional waves. Remind them that in compressional waves particles of material move back and forth parallel to the direction in which the wave itself moves.
Detailed explanation-2: -P wave is the fastest wave. Particle motion consists of alternating compression and dilation. Particle motion is parallel to the direction of propagation (longitudinal).
Detailed explanation-3: -Both P and S waves travel outward from an earthquake focus inside the earth. The waves are often seen as separate arrivals recorded on seismographs at large distances from the earthquake.
Detailed explanation-4: -The P wave propagates at 6 km/sec in rock with particle motions that are parallel to the direction of propagation. The S wave is slower at 4 km/sec and propagates with particle motions that are perpendicular to the direction of propagation.
Detailed explanation-5: -P-waves are predominantly compressional waves. As a P-wave passes, material compresses in the same direction the wave is moving, and then extends back to its original thickness once the wave has passed.