# Earthquake Engineering Questions and Answers – Earthquake Ground Motion Characteristics

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

1. The strong motion characteristics are not dependent on which of the following factors?
a) Fault shape
b) Fault area
c) Distance between ground surface and fault plane
d) Fault moments

Explanation: The characteristics of strong motion are strongly dependent on the nature of faulting. Distance between ground surface and fault plane, stress drop, fault shape and area are some of the source parameters on which the strong motion characteristics are dependent. Fault moments have no effects on strong motion characteristics.

2. Which component of acceleration is used to report ground motion?
a) Vertical
b) Horizontal
c) Tangential

Explanation: Ground motion is primarily reported by the horizontal component of acceleration. We design the structures for vertical loads and the margin of safety is adequate for the vertical forces induced by the earthquake. We do not consider the radial and tangential forces for a structure. Therefore, only horizontal component is used.

3. Earthquakes with MMI between which range were used by Trifunac and Brady to derive a relation between Peak ground acceleration and MMI?
a) I – X
b) II – X
c) III – X
d) V – X

Explanation: Trifunac and Brady used 187 records of 57 western USA earthquakes which had MMI in the range of III – X. They derived a relation between the Peak ground acceleration and MMI using these earthquake data.

4. What is represented by the ratio of Peak ground velocity (PGV) and Peak ground acceleration (PGA)?
a) Multiplying factor
b) Displacement
c) Amplitude
d) Frequency

Explanation: Frequency of the motion is represented by the ratio of Peak ground velocity and Peak ground acceleration. It can also be understood as the period of vibration of a corresponding harmonic wave. This ratio also indicates the significant periods of the ground motion.

5. What is the term given to the maximum earthquake ground motion that is expected to occur once during the design life of the structure?
a) Maximum Credible Earthquake (MCE)
b) Maximum Intensity Earthquake (MIE)
c) Design Basis Earthquake (DBE)
d) Design Mean Earthquake (DME)

Explanation: The earthquake corresponding to the maximum ground motion that is expected to occur once during the design life of the structure is called as Design Basis Earthquake (DBE). Ordinary buildings are designed considering this earthquake. The structure should remain functional during and after this earthquake.

6. The characteristics of strong motion is not dependent on the nature of faulting.
a) True
b) False

Explanation: The characteristics of strong motion in the surrounding area of contributing fault is strongly reliant on the nature of faulting. It depends on the fault shape and its area, stress drop, complexity of slipping process and maximum fault dislocation.

7. Which of the following faults do not reach the earth’s surface and terminates before reaching the surface?
a) Blind fault
b) Reverse fault
c) Ring fault
d) Listric fault

Explanation: The fault which do not reach the earth surface and terminates in the convex upward fold is known as blind fault. This fault cannot be detected and examined as evidences are not available. They have great impact on the ground motion estimation.

8. What is the return period of a Maximum Considered Earthquake (MCE)?
a) 475 years
b) 1000 years
c) 1500 years
d) 2500 years

Explanation: As per the International Building Code (IBC), MCE has a return period of 2500 years. Therefore, the probability of being exceeded in 50 years’ design life of any structure is 2%.

9. What is the range of ad/v2 for the earthquakes which are important from engineering viewpoint?
a) 0.1 – 0.5
b) 0.5 – 1
c) 1 – 10
d) 5 – 15

Explanation: The ratio ad/v2 denotes the sharpness of response spectrum in the velocity region. It ranges between 5-15 for earthquakes of engineering interest. The value of sharpness response for steady-state square acceleration wave is $$\frac{1}{2}$$ and for harmonic motions is 1.

10. Which of the following is the most inaccurate ground motion data?
a) Peak ground displacement
b) Peak ground velocity
c) Peak ground acceleration
d) Effective peak velocity

Explanation: The peak ground displacement is the most inaccurate data of ground motion. The displacement data are generally derived from the acceleration data and as there are errors in filtering and integration of acceleration data, the values of displacement are not that accurate.

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]