ESS 101 B LABORATORY 8 QUIZ GEOLOGIC HAZARDS
EARTHQUAKES AND LANDSLIDES 2026/2027 | Verified 100%
Questions and Answers with Detailed Rationales | Geology
Lab Assessment | Pass Guaranteed - A+ Graded
Domain 1: Earthquake Mechanics and Fault Types (8 Questions)
Q1
A magnitude 6.5 earthquake occurs along a fault where the hanging wall has moved
upward relative to the footwall. The region is characterized by compressional tectonic
stress and mountain building. What type of fault is responsible for this earthquake?
A. Normal fault with tensional stress
B. Reverse fault with compressional stress [CORRECT]
C. Strike-slip fault with shear stress
D. Transform fault with extensional stress
Correct Answer: B
Rationale: Reverse faults are characterized by upward movement of the hanging wall
relative to the footwall, occurring under compressional stress regimes. This fault type is
associated with convergent plate boundaries, mountain building (orogeny), and
shortening of the crust. The description of compressional stress and mountain building
confirms this tectonic setting. Option A is incorrect because normal faults involve
hanging wall moving downward under tensional stress. Option C is incorrect because
strike-slip faults involve horizontal movement with no vertical displacement of hanging
wall/footwall. Option D is incorrect because transform faults are strike-slip boundaries
with lateral movement, not vertical displacement, and are not associated with
,extensional stress. This question aligns with ESS 101 B Laboratory 8 Learning Objective
1.1: identifying fault types from movement characteristics and stress regimes.
Q2
During a laboratory analysis of focal mechanism solutions (beach ball diagrams), you
observe that the first motion of P-waves shows compression in the
northeast-southwest quadrants and dilation in the northwest-southeast quadrants. The
fault plane strikes north-south. What type of faulting is indicated?
A. Normal faulting with east-west extension
B. Thrust faulting with east-west compression [CORRECT]
C. Left-lateral strike-slip faulting
D. Right-lateral strike-slip faulting
Correct Answer: B
Rationale: Focal mechanism solutions display quadrants of compression (black) and
dilation (white). For a north-south striking fault with northeast-southwest compression,
the P-axis (compression) is oriented east-west, indicating east-west shortening. This
corresponds to thrust faulting (low-angle reverse faulting) with horizontal compression
perpendicular to the strike. The north-south striking fault with east-west compression
produces thrust movement. Option A would show north-south extension with vertical
dilation quadrants. Options C and D would show alternating quadrants for strike-slip
motion with different orientations. This question assesses ESS 101 B Learning
Objective 1.3: interpreting focal mechanism solutions to determine fault type and stress
orientation.
Q3 [Data Interpretation]
, The San Andreas Fault system experienced an earthquake with the following
characteristics: horizontal displacement of 3 meters, right-lateral offset of stream
channels, and no significant vertical component. The earthquake occurred at 10 km
depth in a transform boundary setting. What is the fault classification and expected
tsunami potential?
A. Reverse fault; high tsunami potential due to vertical seafloor displacement
B. Normal fault; moderate tsunami potential from hanging wall collapse
C. Right-lateral strike-slip fault; minimal tsunami potential due to lack of vertical
displacement [CORRECT]
D. Left-lateral strike-slip fault; high tsunami potential from coastal displacement
Correct Answer: C
Rationale: The San Andreas is a classic right-lateral strike-slip transform boundary. The
described horizontal displacement, right-lateral stream offset, and absence of vertical
component confirm strike-slip motion. Tsunamis require vertical displacement of water
column; pure strike-slip motion generates minimal tsunami potential because horizontal
displacement does not displace significant water volume. Option A is incorrect because
reverse faults show vertical displacement. Option B is incorrect because normal faults
show vertical displacement opposite to described. Option D is incorrect because the
offset is right-lateral (opposite to left-lateral), and tsunami potential remains minimal.
This aligns with ESS 101 B Learning Objective 1.2: relating fault type to tsunami
generation potential.
Q4
In a subduction zone setting, the 2011 Tōhoku earthquake (M9.1) occurred at the plate
interface. Analysis shows the fault rupture extended from 24 km depth to the seafloor,
with maximum slip of 50 meters. What combination of factors contributed to the
massive tsunami generation?
EARTHQUAKES AND LANDSLIDES 2026/2027 | Verified 100%
Questions and Answers with Detailed Rationales | Geology
Lab Assessment | Pass Guaranteed - A+ Graded
Domain 1: Earthquake Mechanics and Fault Types (8 Questions)
Q1
A magnitude 6.5 earthquake occurs along a fault where the hanging wall has moved
upward relative to the footwall. The region is characterized by compressional tectonic
stress and mountain building. What type of fault is responsible for this earthquake?
A. Normal fault with tensional stress
B. Reverse fault with compressional stress [CORRECT]
C. Strike-slip fault with shear stress
D. Transform fault with extensional stress
Correct Answer: B
Rationale: Reverse faults are characterized by upward movement of the hanging wall
relative to the footwall, occurring under compressional stress regimes. This fault type is
associated with convergent plate boundaries, mountain building (orogeny), and
shortening of the crust. The description of compressional stress and mountain building
confirms this tectonic setting. Option A is incorrect because normal faults involve
hanging wall moving downward under tensional stress. Option C is incorrect because
strike-slip faults involve horizontal movement with no vertical displacement of hanging
wall/footwall. Option D is incorrect because transform faults are strike-slip boundaries
with lateral movement, not vertical displacement, and are not associated with
,extensional stress. This question aligns with ESS 101 B Laboratory 8 Learning Objective
1.1: identifying fault types from movement characteristics and stress regimes.
Q2
During a laboratory analysis of focal mechanism solutions (beach ball diagrams), you
observe that the first motion of P-waves shows compression in the
northeast-southwest quadrants and dilation in the northwest-southeast quadrants. The
fault plane strikes north-south. What type of faulting is indicated?
A. Normal faulting with east-west extension
B. Thrust faulting with east-west compression [CORRECT]
C. Left-lateral strike-slip faulting
D. Right-lateral strike-slip faulting
Correct Answer: B
Rationale: Focal mechanism solutions display quadrants of compression (black) and
dilation (white). For a north-south striking fault with northeast-southwest compression,
the P-axis (compression) is oriented east-west, indicating east-west shortening. This
corresponds to thrust faulting (low-angle reverse faulting) with horizontal compression
perpendicular to the strike. The north-south striking fault with east-west compression
produces thrust movement. Option A would show north-south extension with vertical
dilation quadrants. Options C and D would show alternating quadrants for strike-slip
motion with different orientations. This question assesses ESS 101 B Learning
Objective 1.3: interpreting focal mechanism solutions to determine fault type and stress
orientation.
Q3 [Data Interpretation]
, The San Andreas Fault system experienced an earthquake with the following
characteristics: horizontal displacement of 3 meters, right-lateral offset of stream
channels, and no significant vertical component. The earthquake occurred at 10 km
depth in a transform boundary setting. What is the fault classification and expected
tsunami potential?
A. Reverse fault; high tsunami potential due to vertical seafloor displacement
B. Normal fault; moderate tsunami potential from hanging wall collapse
C. Right-lateral strike-slip fault; minimal tsunami potential due to lack of vertical
displacement [CORRECT]
D. Left-lateral strike-slip fault; high tsunami potential from coastal displacement
Correct Answer: C
Rationale: The San Andreas is a classic right-lateral strike-slip transform boundary. The
described horizontal displacement, right-lateral stream offset, and absence of vertical
component confirm strike-slip motion. Tsunamis require vertical displacement of water
column; pure strike-slip motion generates minimal tsunami potential because horizontal
displacement does not displace significant water volume. Option A is incorrect because
reverse faults show vertical displacement. Option B is incorrect because normal faults
show vertical displacement opposite to described. Option D is incorrect because the
offset is right-lateral (opposite to left-lateral), and tsunami potential remains minimal.
This aligns with ESS 101 B Learning Objective 1.2: relating fault type to tsunami
generation potential.
Q4
In a subduction zone setting, the 2011 Tōhoku earthquake (M9.1) occurred at the plate
interface. Analysis shows the fault rupture extended from 24 km depth to the seafloor,
with maximum slip of 50 meters. What combination of factors contributed to the
massive tsunami generation?
