Question
Download Solution PDFWhich of statement is NOT correct regarding the earthquake waves?
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFThe correct answer is Option 1.
Key Points
- Seismic Waves (Earthquake Waves)
- Seismic waves are waves of energy caused by earthquakes or an explosion. They are the energy that travels through the earth and is recorded on seismographs.
- Earthquake waves are basically of two types — body waves and surface waves.
- Body waves are generated due to the release of energy at the focus and move in all directions traveling through the body of the earth. Hence, the name body waves.
- There are two types of body waves. They are called P and S-waves.
- P-waves move faster and are the first to arrive at the surface. Hence, Statement 3 is correct.
- These are also called ‘primary waves’. Hence, Statement 4 is correct
- The P-waves are similar to sound waves.
- They travel through gaseous, liquid, and solid materials. Hence, Statement 1 is not correct.
- P-waves are also called the longitudinal waves.
- The seismographs located beyond 145° from epicenters; record the arrival of P-waves, but not that of S-waves.
- P-waves create density differences in the material leading to stretching (rarefaction) and squeezing (compression) of the material.
- S-waves arrive at the surface with some time lag. These are called secondary waves.
- An important fact about S-waves is that they can travel only through solid materials. Hence, Statement 2 is correct.
- There exist some specific areas where the waves are not reported. Such a zone is called the ‘shadow zone’.
- A zone between 105° and 145° from the epicenter was identified as the shadow zone for both types of waves.
- The shadow zone of the S-wave is much larger than that of the P-wave.
- The shadow zone of S-waves is not only larger in extent but it is also a little over 40 percent of the earth's surface.
Last updated on May 28, 2025
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