Earthquake Seismology - Advanced topics in Geophysics - Geology & Geophysics Previous Year Questions

1

2009 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2009

A vast majority of earthquake sources are often linked to

A

inner core

B

outer core

C

brittle part of the earth’s crust

D

molten part of earth’s mantle

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2

2009 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2009

The teleseismic rays are those that arrive at a seismometer for a distance greater than

A

18°

B

28°

C

38°

D

48°

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3

2009 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2009

Which is the parameter for measuring the size of the earthquake that does not need an instrumental record ?

A

Richter Magnitude

B

Intensity

C

Moment

D

M_w

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4

2009 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2009

Match the following:
Group I
P. Primary wave
Q. Secondary wave
R. Rayleigh wave
S. Love wave
Group II
1. Propagate along surface of the medium
2. Particle motion is orthogonal to direction of propagation
3. Particle motion describes a retrograde ellipse
4. Particle motion in the direction of propagation

A

P-3, Q-4, R-1, S-2

B

P-1, Q-4, R-2, S-3

C

P-1, Q-3, R-2, S-4

D

P-4, Q-2, R-3, S-1

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5

2010 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2010

The seismic energy released in an earthquake of magnitude \(M_s = 7.0\) is about ________ times that released in an earthquake of \(M_s = 6.0\).

A

10

B

32

C

64

D

100

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6

2010 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2010

In the figure given below '-' represents dilatation and '+' represents compression. The fault plane solution of an earthquake with strike-slip mechanism is represented by

A

P

B

Q

C

R

D

S

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7

2010 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2010

The anelastic attenuation of seismic energy depends on

A

quality factor

B

particle acceleration

C

stress drop

D

particle velocity

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8

2011 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2011

Shadow zones for direct P- and S-waves lies between

A

102° to 142° for both direct P- and S-waves

B

102° to 180° for direct P- wave and 102° to 142° for direct S-wave

C

102° to 180° for both direct P- and S-waves

D

102° to 142° for direct P- wave and 102° to 180° for direct S-wave

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9

2012 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2012

The seismic slip of a fault after an earthquake is measured to be 0.5 m and the fault area is estimated to be 250 km². The rigidity of the medium surrounding the fault is 30 GPa.
The seismic moment (in Nm) of the earthquake is

A

\(3.75 \times 10^{18} \)

B

\(3.75 \times 10^{16} \)

C

\(3.75 \times 10^{14} \)

D

\(3.75 \times 10^{12} \)

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10

2012 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2012

Based on the above, the moment magnitude of the earthquake is

A

5.15

B

5.36

C

6.35

D

7.25

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11

2013 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2013

The type of wave that arrives first at a station from an earthquake hypocenter is

A

P-wave

B

S-wave

C

Rayleigh wave

D

Love wave

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12

2013 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2013

Which of the following ways of measuring the size of an earthquake does not require instrumental recording?

A

Richter magnitude

B

Moment

C

Mw

D

Intensity

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13

2013 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2013

Wadati diagram is a plot of the difference in P- and S- wave arrival times against the arrival time of P-wave. It helps in estimating the

A

velocity of P-wave.

B

velocity of S-wave.

C

time of occurrence of earthquake.

D

hypocenter of earthquake.

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14

2014 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2014

As compared to large earthquakes, small earthquakes are

A

more frequent and caused by short fault slip and long rupture lengths

B

more frequent and caused by long fault slip and short rupture lengths

C

less frequent and caused by short fault slip and short rupture lengths

D

more frequent and caused by short fault slip and short rupture lengths

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15

2014 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2014

For earthquakes of magnitudes 6 and 7, the seismic wave amplitudes are A₆ and A₇ and the radiated energies are E₆ and E₇ respectively. Which one of the following is true?

A

A₇ ≈ (7/6) A₆ and E₇ ≈ 10 E₆

B

A₇ ≈ 10 A₆ and E₇ ≈ 100 E₆

C

A₇ ≈ 10 A₆ and E₇ ≈ (7/6) E₆

D

A₇ ≈ 10 A₆ and E₇ ≈ 32 E₆

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16

2016 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2016

Which one of the following statements is CORRECT for the stress drop (Δσ) of an earthquake?

A

Large slip on a small fault will cause more stress drop.

B

Small slip on a large fault will cause more stress drop.

C

Stress drop is inversely proportional to the slip of the fault.

D

Stress is directly proportional to the rupture dimension.

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17

2016 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2016

The energy released by an earthquake of magnitude 7 is _______ times the energy released by an earthquake of magnitude 4 (use Kanamori’s formula).

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18

2022 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2022

The difference in arrival times of P- and S-waves generated by an earthquake and recorded at a seismological station is one second. Assuming a homogeneous and isotropic Earth, a P-wave velocity (Vₚ) of 3 km/s, the ratio of P- to S-wave velocities (Vₚ/Vₛ) of 2.0, the distance between the station and the hypocenter is ______ km. [round off to 1 decimal place]

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19

2022 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2022

The difference in arrival times of P- and S-waves generated by an earthquake and recorded at a seismological station is one second. Assuming a homogeneous and isotropic Earth, a P-wave velocity ($V_P$) of 3 km/s, the ratio of P- to S-wave velocities ($V_P/V_S$) of 2.0, the distance between the station and the hypocenter is __________ km. [round off to 1 decimal place]

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20

2022 · Geology & Geophysics · Advanced topics in Geophysics · Earthquake Seismology

Geology & Geophysics (GG) 2022

Which ONE of the following P-phases represents a reflection from the Moho?

A

Pn

B

Pg

C

P*

D

PmP

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