I. In a seismograph, P waves are recorded earlier than S waves.
II. 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?
Seismograph and Seismic Wave Analysis
This section analyzes the two statements regarding seismic waves and their recording on a seismograph.
P Wave Arrival Timing on Seismograph
Statement I claims that P waves are recorded earlier than S waves in a seismograph. This is accurate because P waves (Primary waves) are compressional waves that travel faster through the Earth's interior than S waves (Secondary waves), which are shear waves.
Consequently, the first seismic waves to arrive at a seismograph are the P waves. Thus, Statement I is correct.
Particle Motion in P and S Waves
Statement II describes the particle motion associated with P and S waves. This statement is also correct:
- P waves are longitudinal waves. The particles in the medium oscillate back and forth in the direction of wave propagation.
- S waves are transverse waves. The particles in the medium oscillate vertically (up and down), perpendicular (at right angles) to the direction of wave propagation.
This distinction in particle movement is a fundamental characteristic of these seismic wave types.
Combined Assessment of Seismic Statements
Both Statement I, concerning the earlier arrival of P waves, and Statement II, describing the distinct particle motions of P and S waves, are factually correct based on seismological principles.
Important Questions from Geomorphology
Which one of the following is not an igneous rock?
Which of the following statements is/are correct?
1. Hypocenter is the point on the surface of the Earth, nearest to the focus.
2. Velocity of earthquake waves is higher in denser materials.
3. P waves move faster and are the first to arrive at the surface of the Earth.
Select the correct answer using the code given below:
Which one of the following is the lowermost/innermost intrusive igneous rock?
The formation of ‘tors’ on small rocky hills is associated with which among the following?
Which one of the following statements about metamorphic rocks is not correct?
