Question
Download Solution PDFWhich of the following statements is/are correct?
1. Secondary waves are compressional waves that are longitudinal in nature.
2. Primary waves are shear waves that are transverse in nature.
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFThe correct answer is Neither 1 nor 2.
Key Points
Primary Waves:
- Primary waves (P-waves) are compressional waves that are longitudinal in nature. Hence, Statement 1 is incorrect.
- P waves are pressure waves that travel faster than other waves through the earth to arrive at a seismograph.
- These waves can travel through any type of material, including fluids as well as solid.
- They travel faster than S-waves.
Secondary Waves:
- Secondary waves (S-waves) are shear waves that are transverse in nature. Hence, Statement 2 is incorrect.
- S-waves can travel only through solids, as fluids (liquids and gases) do not support shear stresses.
- S-waves are slower than P-waves.
Important Points
- Earthquake waves get recorded in seismographs located at far off locations.
- It has been inferred indirectly using the time of travel of refracted and reflected seismic waves created by earthquakes.
- The changes in seismic velocity between different layers cause refraction due to Snell's law.
- S wave shadow zone forms the boundary of the outer core as it is in a liquid state.
- There exist some specific areas where the waves are not reported. Such a zone is called the ‘shadow zone’.
Last updated on Jul 9, 2025
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