Consider the following statements: 1. In a seismograph, P waves are recorded earlier than S waves. 2. In P waves, the individual particles vibrate to and fro in the direction of wave propagation whereas in S waves, the particles vibrate up and down at right angles to the direction of wave propagation. Which of the statements given above is/are correct?

Question

GSEasyPrelims 2023Physical Geography

Consider the following statements:

In a seismograph, P waves are recorded earlier than S waves.
In P waves, the individual particles vibrate to and fro in the direction of wave propagation whereas in S waves, the particles vibrate up and down at right angles to the direction of wave propagation.

Which of the statements given above is/are correct?

Explanation

Statement 1 is correct: In a seismograph, P waves are recorded earlier than S waves. This is true because P waves, also known as Primary waves, are the first to be recorded by a seismograph during an earthquake. They are faster and hence, reach the recording instrument before the S waves.

Statement 2 is correct: P waves are longitudinal or compressional waves, which means the particles in these waves vibrate in the same direction as the wave propagation. On the other hand, S waves, or Secondary waves, are transverse waves, where the particle motion is perpendicular to the direction of wave propagation. Therefore, both statements are correct.