# Earthquake Engineering Questions and Answers – Earthquake Size

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

1. Which of the following is not used to measure the intensity of an earthquake?
a) Mercalli Scale
b) Medvedev Scale
c) Rossi Forel Scale
d) Reid’s Scale

Explanation: Reid’s scale is not a scale for measuring earthquake. Mercalli scale was developed in 1902 and later modified in 1931 and know as Medvedev scale, Rossi forel scale in 1900.

2. The MSK scale does not depend on which of these parameters?
a) Type of structure
b) Percentage of damage
d) Location of structure

Explanation: The MSK or Mercalli scale is used to scale earthquakes on the basis of the damage it has caused to existing structures. It does not consider the zone in which the structure is located.

3. The intensity of earthquake in an MSK scale ranges from one to __________________
a) Twelve
b) Four
c) Eight
d) Six

Explanation: The MSK scale classifies the type of structure into three categories and the type of damage into five categories. On the basis of these data it has put forth twelve different intensities of earthquake.

4. A map showing regions of same seismic intensity in form of contours is called _______________
a) Isoseismic map
b) Isohaline map
c) Isobar map
d) Isozymes map

Explanation: A map with contours bounding areas of same seismic intensity is called isoseismic map. An isoseismic map is used for classifying a region into a number of zones on the basis of earthquake intensity. These zones can be used by the earthquake researchers to predict the intensity of earthquake that may occur in that region.

5. How are magnitudes of the earthquake classified?
a) Richter and duration magnitude
b) Reid’s and Mercalli magnitude
c) Richter and Mercalli magnitude
d) Reid’s and duration magnitude

Explanation: The earthquake magnitude is classified as Richter and duration magnitude. Richter magnitude was developed by Dr. Charles Richter and was based on past earthquake data whereas Duration magnitude was developed by Aki and Chouet and depended upon the duration for which occurs and unlike Richter scale it is independent of the distance of the seismometer from the epicentre.

6. The moment magnitude of an earthquake is measured by measuring which of these phenomena in an earthquake?
a) Moment released during earthquake rupture
b) Displacement due to ground shaking
c) Energy released due to pounding of two masses
d) Duration required to achieve static equilibrium

Explanation: The conventional magnitude scales (ML, mB or MS) are based on maximum amplitude and period of body waves or surface waves and they underestimate the intensity of an earthquake. A moment magnitude scale measures these intensities by measuring the moment release during earthquake rupture which is appreciably on a conservative side.

7. The moment released in a moment magnitude scale does not depend on which of these parameters?
a) Physical dimensions of rupture
b) Shear strength of the rock
c) Average displacement of fault plane
d) Friction coefficient between the rock surface

Explanation: The moment of rupture is given by the expression
where, p is the shear strength of rock, A is the area of fault and d is the average displacement of fault.

8. The graphical representation of past earthquake data in form of a plot of the distance of the seismometer from the epicentre in Km and the amplitude in mm was given by which of these researchers?
a) Richter
b) Mercalli
c) Medvedev
d) Reid

Explanation: Richter collected data of past earthquakes occurred in South California and prepared a graphical plot. This graphical plot was later modified and is now being used to classify various earthquakes on the basis of the peak ground amplitude and their distances from the earthquake epicentre.

9. Which of these scales is a logarithmic scale?
a) Mercalli scale
b) Medvedev scale
c) Richter scale
d) Rossi forel scale

Explanation: Richter scale is a logarithmic scale. Mercalli, Medvedev and Rossi forel scale are a statistical scale.

10. The greatest recorded earthquake in the Indian history as per the Richter scale is _____________
a) 7.7
b) 8.1
c) 8.6
d) 9.6

Explanation: India recorded the greatest magnitude of Earthquake on 15 August 1950 in Assam. The epicentre was located in Tibet. It is also called the Medog earthquake.

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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