# Earthquake Engineering Questions and Answers – Nature of Ground Motion

This set of Earthquake Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Nature of Ground Motion”.

1. The duration of shaking of ground during an earthquake is ______________ to the magnitude of earthquake.
a) Directly proportional
b) Inversely proportional
c) Independent of
d) Similar
View Answer

Answer: a
Explanation: A greater magnitude of earthquake will result in a great fault rupture area. This nature of the rock results in a greater release of seismic energy which is proportional to the frequency of the ground vibration.

2. Which of the following phenomena occurs due to the Doppler effect of seismic waves?
a) Rupture directivity effect
b) Fling effect
c) Hanging wall effect
d) Path effect
View Answer

Answer: a
Explanation: Rupture directivity effect is a manifestation of Doppler’s effect in seismic waves. As the seismic waves move forward, the intensity of waves felt along the direction of rupture is more, whereas the direction from which the seismic waves are moving away is less.

3. The phenomena which causes a permanent displacement in the ground across a ruptured fault is called as ______________
a) Rupture directivity effect
b) Fling effect
c) Hanging wall effect
d) Path effect
View Answer

Answer: b
Explanation: Fling effect is the permanent displacement of the ground under seismic effects. The displacement of the ground is measured in terms of fling step. It is highest for strike-slip fault and lesser for reverse and normal fault.
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4. In dip slip faulting the fling effect and the directivity effect occurs on __________________
a) Strike normal component
b) Strike parallel component
c) Slip parallel component
d) Slip normal component
View Answer

Answer: a
Explanation: In a dip slip condition the fling and directivity effect occurs on the strike normal component whereas in a strike-slip faulting the fling effect occurs on the strike parallel surface and directivity effect occurs on the strike normal surface.

5. Hanging wall effects results in tremors lasting for a duration of less than 1 seconds.
a) True
b) False
View Answer

Answer: a
Explanation: Hanging wall effect occurs because of the concentration of much of the faults on the hanging wall side then on the foot wall side. Unlike rupture directivity effect the rupture does not propagate along the fault plane.

6. As the seismic waves advance in a body the specific energy of the seismic waves ___________ with increasing wave fronts.
a) Increase
b) Decrease
c) Remain same
d) Decrease and then increase
View Answer

Answer: b
Explanation: As the seismic waves advance in a body the specific energy of the seismic waves increase with increasing wave front. This is mainly because the volume over which the seismic waves advances increases leading to a decrease in the specific energy of the seismic waves.

7. The phenomena of decrease of amplitude of seismic waves because of an increase in the volume of the medium through which it propagates is called as _____________
a) Rupture directivity effect
b) Fling effect
c) Hanging wall effect
d) Path effect
View Answer

Answer: d
Explanation: When the earthquake waves are released from a point below the ground surface the body waves travel in form of spherical wave fronts. The specific energy of the seismic waves reduces leading to a reduction in wave amplitude. This reduction in wave amplitude while travelling along a path in the body is called as path effect.
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8. Which of the following local site parameters influence the ground motion during an earthquake?
a) Topography of the region
b) Basin effects
c) Local ground response
d) Location of fault
View Answer

Answer: d
Explanation: The fault location is studied under the phenomena of source and path effect. Local site effect includes the surface topography of the region, basin effects and the local ground response.

9. A more comprehensive form of ground motion attenuation relation was needed because _______
a) It did not consider regional geology and site conditions
b) The relation of acceleration with earthquakes magnitude was not considered
c) The relation of acceleration with earthquakes distance was not considered
d) Non linear dependence of attenuation was not considered
View Answer

Answer: d
Explanation: The relation needed a non linear dependence of attenuation of ground motion with distance, soil conditions, soil types and location of measurement of ground motion.
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10. For estimating the maximum acceleration at a site, one needs to _______________
a) Estimate the upper limit magnitude and lower limit of distance
b) Estimate the lower limit magnitude and upper limit of distance
c) Estimate the upper limit magnitude and upper limit of distance
d) Estimate the lower limit magnitude and lower limit of distance
View Answer

Answer: a
Explanation: In the equation, acceleration is directly proportional to magnitude and inversely proportional to distance. Hence, for estimating the maximum acceleration at site, one needs to estimate the upper limit magnitude and lower limit of distance.

Sanfoundry Global Education & Learning Series – Earthquake Engineering.

To practice all areas of Earthquake Engineering, here is complete set of Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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