This set of Earthquake Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Seismic Waves”.
1. Seismic waves are classified as _______________
a) Surface waves and body waves
b) Compression waves and rarefaction waves
c) Rayleigh waves and Lindbergh waves
d) Shear waves and bending waves
View Answer
Explanation: Seismic waves are classified as surface waves and body waves. Surface waves travel only along the surface on which it is formed whereas body waves travel in all the directions and to all the depths of the medium.
2. Compressional waves and shear waves are which type of seismic waves?
a) Body waves
b) Surface waves
c) Rayleigh waves
d) Love waves
View Answer
Explanation: Compressional waves and shear waves travel in all directions. Hence they are body waves. Compressional waves are sometimes called as primary waves (P-waves) whereas shear waves are also called secondary waves (S-waves).
3. Which of these seismic waves are acoustical in nature?
a) Shear waves
b) Compressional waves
c) Rayleigh waves
d) Love waves
View Answer
Explanation: Compressional waves are acoustical in nature because they require a medium for propagation and follow all laws of acoustics. They cause volumetric changes in the medium through which they travel.
4. Which of these seismic waves do not propagate through fluids?
a) Shear waves
b) Love waves
c) Rayleigh waves
d) Compressional waves
View Answer
Explanation: Shear waves do not cause volumetric change in the material but distort the shape of the material. Hence, the material through which they propagate needs to have adequate shear strength. Fluids have no shear capacity and hence they do not travel through fluids.
5. A Rayleigh wave occurs as a result of combination of which of these waves?
a) P waves and SV waves
b) P waves and SH waves
c) S waves and PV waves
d) S waves and PH waves
View Answer
Explanation: Rayleigh waves occur as a result of out of phase vibration of P and SV waves. The out of phase vibration results in the wave travelling in an elliptical path along the surface of the body.
6. The velocity of the Rayleigh waves through a medium depends on which of these parameter of the medium?
a) Poisson ratio
b) Young’s modulus
c) Shear modulus
d) Torsional rigidity
View Answer
Explanation: The velocity of Rayleigh wave depends on the Poisson ratio of the medium through which it propagates. It is equal to the 0.9194 times the velocity of S-wave in Poisson’s solid.
7. Which of these statements are correct?
a) P and S waves are surface waves
b) P and S waves travel in an elliptical path
c) P waves travel faster than S-waves
d) Velocity of P and S waves are independent of medium properties
View Answer
Explanation: The velocity of S-waves is dependent on the shear strength of the material whereas velocity of P-waves is independent of the shear strength. P-waves travel by applying a force in the direction of propagation and hence energy is quickly transmitted by them.
8. Which of these waves are the first to arrive at seismic stations?
a) P waves
b) S waves
c) Q waves
d) L waves
View Answer
Explanation: The arrival time of seismic waves depends on the velocity of propagation. P-waves have the highest velocity compared to other waves. Hence, they are the first ones to arrive at seismic stations.
8. Which of these waves cannot travel through the outer core of the earth?
a) P waves
b) S waves
c) Q waves
d) L waves
View Answer
Explanation: S waves are shear waves which require a material with adequate shear strength for propagation. The outer core of the earth is mainly composed of molten iron which has no shear strength in its fluid state. Hence S waves cannot travel through the outer core.
9. Seismic waves have made possible to study the ________________
a) Interior of the earth
b) Formation of universe
c) Oceanic waves
d) Earth’s magnetism
View Answer
Explanation: The seismic waves travel in different medium with different velocities. They travel for long ranges and easily detectable by various electronic instruments. Hence, they are widely used to study the interior of the earth.
10. Which of the following instrument is used to record the seismic waves?
a) Seismometer
b) Seismogram
c) Seismograph
d) Seismologist
View Answer
Explanation: A seismometer is used to record the seismic waves. The seismogram are the records given out by a seismograph in a seismometer. Seismologist is a person who does seismic studies.
Sanfoundry Global Education & Learning Series – Earthquake Engineering.
To practice all areas of Earthquake Engineering, here is complete set of Multiple Choice Questions and Answers.
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