# Earthquake Engineering Questions and Answers – Probabilistic Approach

This set of Earthquake Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Probabilistic Approach”.

1. Who developed the probabilistic estimations of ground motion?
a) Algermissen and Perkins
b) Wegener
c) Wells and Coppersmith
d) Esteva and Villaverde

Explanation: Algermissen and Perkins developed the methodology and procedures for probabilistic estimations of ground motion. Wegener proposed the theory of plate tectonics. Wells and Coppersmith gave the relation between fault rupture parameters and moment magnitude. Esteva and Villaverde derived the attenuation relationships for peak ground motions.

2. Which statistical tool is used for analysis in probabilistic approach?
a) Gutenberg-Richter law
b) Attenuation law
c) Eulerian analysis
d) Bayesian analysis

Explanation: Bayesian analysis is the statistical tool used for analysis and evaluation of ground acceleration in the probabilistic approach. Gutenberg-Richter law gives the relation between the magnitude and total number of earthquakes in a specified region. Attenuation law is used to study the effects of distant earthquakes on the faults.

3. Location of which of the following earthquake is considered as temporarily stationary in the modular source?
a) Intraplate earthquakes
b) Floating earthquakes
c) Interplate earthquakes
d) Volcanic earthquakes

Explanation: Location of floating earthquakes is considered as temporarily stationary and spatially homogeneous in the modular space. Floating earthquakes are the ones which are not associated with faults. The earthquake is equally likely in both longitude and latitude direction.

4. What is the peak acceleration exceedance probability for atomic power plant?
a) 0.05
b) 0.1
c) 0.25
d) 0.33

Explanation: The exceedance probability for atomic power plant is taken as 0.05. The value of probability is selected on the basis of consequences of failure of that particular structure. The failure of an atomic power plant can cause severe damage to life, environment and property. Therefore, a low exceedance probability is considered and the structure is designed according to that.

5. Which maps indicate the vulnerable region to a particular natural calamity?
a) Topographic map
b) Political map
c) geologic map
d) Hazard map

Explanation: A hazard map indicates the region which is vulnerable to any natural calamity or hazard. It includes earthquake, landslide, volcanos, etc. These maps provide the most accurate and detailed information regarding the probability of occurrence of a particular hazard. It helps the Engineers to design the buildings, highways, bridges and utilities which can withstand that hazard.

6. A soft storey is a storey whose lateral stiffness is less than the storey above it.
a) True
b) False

Explanation: A soft storey is a type of vertical irregularity. It is a storey whose lateral stiffness is less than the storey above it. According to IBC, if there is 70% or more reduction from one floor to the next floor then it is considered as a soft storey. It generally occurs because of large openings or tall storey height in comparison to the adjacent stories.

7. For which of the following structures, exceedance probability for peak motions is taken as 0.25?
a) Buildings
b) Nuclear power plant
c) Dams
d) Highways

Explanation: The exceedance probability for dams is taken as 0.25. The value of probability is selected on the basis of consequences of failure of that particular structure. The failure of an atomic power plant can cause severe damage to life, environment and property and so its value is 0.05. The consequences of failure for residential buildings and highways are less severe in comparison to dams.

8. What is the idealized width of a slipped fault for magnitude 6.5?
a) 30 km
b) 20 km
c) 40 km
d) 26 km

Explanation: According to McGuire, the idealized width of a slipped fault for earthquake for a magnitude 6.5 is 30 km. The focal depth is taken as 20 km. The hypocentral distance for an earthquake of magnitude 6.5 is 26 km. 40 km is the empirical constant used in the attenuation law which correlates PGA with various earthquake parameters.

9. Which of the following cities fall in seismic zone V?
b) Bhuj
c) Mumbai
d) Bangalore

Explanation: Bhuj falls in seismic zone V. The Indian standard code IS 1893 2016 has classified India into four earthquake zones from zone II to zone V. Ahmedabad and Mumbai are in zone III whereas Bangalore is in zone II.

10. Which of the following is not an assumption in the probabilistic approach?
a) Available data is not exhaustive
b) Contains error in magnitude
c) Available data is exhaustive
d) Contains error in locations

Explanation: While carrying out analysis in probabilistic approach, we do not assume available data as exhaustive data. Analysis is carried out with the assumptions that the available data is not exhaustive and it contains error in depth estimates, locations, magnitude etc. Bayesian analysis is used to carry out this analysis.

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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