California Professional Geologist
Examination with Practice Questions And
Correct Answers
1. A coastal aquifer in California exhibits chloride concentrations increasing with
depth, while hydraulic head remains relatively uniform. Which process best explains
this distribution?
A. Upward migration of connate seawater due to over-pumping
B. Density-driven saltwater intrusion from the ocean
C. Diffusion of chloride from marine sediments
D. Irrigation return flow concentrating salts
Answer: C. Diffusion of chloride from marine sediments
Rationale: Uniform hydraulic head with depth argues against active density-driven flow
(B) or upconing (A). Diffusive transport from underlying marine sediments (C) can produce
a stable chloride profile without head gradients. Irrigation return flow (D) typically affects
shallow depths and would show a different pattern.
2. Under the California Environmental Quality Act (CEQA), which threshold best
determines if a project requires a mandatory finding of significance for geology?
A. Any excavation exceeding 10,000 cubic yards
B. Location within a designated seismic hazard zone
C. Presence of expansive soils on-site
D. Project site within 100 feet of a fault
Answer: B. Location within a designated seismic hazard zone
Rationale: CEQA Appendix G identifies location within a seismic hazard zone as a
mandatory significance threshold (B). Excavation volume (A) is not a CEQA trigger,
expansive soils (C) may be mitigated, and proximity to a fault (D) is assessed but not
automatically significant without further analysis.
Page 1 of 82
,3. A rock core from a Franciscan mélange shows blocks of greywacke in a sheared
serpentinite matrix. Which tectonic setting is most consistent with this assemblage?
A. Passive continental margin
B. Subduction zone accretionary prism
C. Mid-ocean ridge transform fault
D. Continental rift basin
Answer: B. Subduction zone accretionary prism
Rationale: Franciscan mélanges with exotic blocks in serpentinite matrix are classic
subduction accretionary prism assemblages (B). Passive margins (A) lack such
deformation, transform faults (C) produce different lithologies, and rift basins (D) are
dominated by sedimentary fill.
4. In a liquefaction hazard assessment, which combination of factors most increases
susceptibility in a clean sand deposit?
A. High relative density and deep water table
B. Low plasticity index and high groundwater table
C. High fines content and low saturation
D. Well-graded gravel and shallow bedrock
Answer: B. Low plasticity index and high groundwater table
Rationale: Liquefaction susceptibility is highest in loose, clean sands with low plasticity
and shallow groundwater (B). High density (A) reduces risk, high fines (C) increases
resistance, and gravel (D) is generally not liquefiable.
Page 2 of 82
,5. A groundwater model calibrated to historic data predicts a steep cone of depression.
Which parameter is most critical to verify before using the model for long-term yield
analysis?
A. Specific yield of the confining layer
B. Hydraulic conductivity of the aquifer
C. Recharge rate from precipitation
D. Storativity of the aquifer
Answer: B. Hydraulic conductivity of the aquifer
Rationale: Hydraulic conductivity (B) controls the shape and extent of the cone of
depression. Specific yield (A) affects unconfined storage, recharge (C) influences long-term
budgets, and storativity (D) is key for transient storage but less critical for steady-state
drawdown shape.
6. Which California regulation specifically governs the cleanup of petroleum
hydrocarbons in soil and groundwater?
A. CERCLA
B. RCRA
C. California Code of Regulations Title 23, Division 3, Chapter 16
D. Clean Water Act
Answer: C. California Code of Regulations Title 23, Division 3, Chapter 16
Rationale: Title 23, CCR, Division 3, Chapter 16 (C) is the California UST cleanup
regulation. CERCLA (A) and RCRA (B) are federal, and the Clean Water Act (D) addresses
surface water quality, not underground storage tank cleanup.
Page 3 of 82
, 7. A seismic refraction survey shows a low-velocity layer beneath a high-velocity layer.
Which interpretation is most plausible?
A. A buried channel filled with saturated sediments
B. A velocity inversion indicating a fault zone
C. A normal sequence of consolidated rock
D. A shallow bedrock high
Answer: B. A velocity inversion indicating a fault zone
Rationale: A low-velocity layer beneath a high-velocity layer is a velocity inversion (B),
often caused by faulting or fracturing. Buried channels (A) typically show lower velocities
above higher ones, normal sequences (C) show increasing velocity with depth, and bedrock
highs (D) produce higher velocities.
8. In California, which agency has primary responsibility for reviewing and approving
geologic reports for subdivision projects under the Subdivision Map Act?
A. California Geological Survey
B. State Water Resources Control Board
C. County or city planning department
D. California Department of Fish and Wildlife
Answer: C. County or city planning department
Rationale: Local planning departments (C) review geologic reports for subdivisions under
the Subdivision Map Act. The California Geological Survey (A) provides technical input
but does not approve, the Water Board (B) handles water quality, and Fish and Wildlife (D)
addresses biological resources.
Page 4 of 82
Examination with Practice Questions And
Correct Answers
1. A coastal aquifer in California exhibits chloride concentrations increasing with
depth, while hydraulic head remains relatively uniform. Which process best explains
this distribution?
A. Upward migration of connate seawater due to over-pumping
B. Density-driven saltwater intrusion from the ocean
C. Diffusion of chloride from marine sediments
D. Irrigation return flow concentrating salts
Answer: C. Diffusion of chloride from marine sediments
Rationale: Uniform hydraulic head with depth argues against active density-driven flow
(B) or upconing (A). Diffusive transport from underlying marine sediments (C) can produce
a stable chloride profile without head gradients. Irrigation return flow (D) typically affects
shallow depths and would show a different pattern.
2. Under the California Environmental Quality Act (CEQA), which threshold best
determines if a project requires a mandatory finding of significance for geology?
A. Any excavation exceeding 10,000 cubic yards
B. Location within a designated seismic hazard zone
C. Presence of expansive soils on-site
D. Project site within 100 feet of a fault
Answer: B. Location within a designated seismic hazard zone
Rationale: CEQA Appendix G identifies location within a seismic hazard zone as a
mandatory significance threshold (B). Excavation volume (A) is not a CEQA trigger,
expansive soils (C) may be mitigated, and proximity to a fault (D) is assessed but not
automatically significant without further analysis.
Page 1 of 82
,3. A rock core from a Franciscan mélange shows blocks of greywacke in a sheared
serpentinite matrix. Which tectonic setting is most consistent with this assemblage?
A. Passive continental margin
B. Subduction zone accretionary prism
C. Mid-ocean ridge transform fault
D. Continental rift basin
Answer: B. Subduction zone accretionary prism
Rationale: Franciscan mélanges with exotic blocks in serpentinite matrix are classic
subduction accretionary prism assemblages (B). Passive margins (A) lack such
deformation, transform faults (C) produce different lithologies, and rift basins (D) are
dominated by sedimentary fill.
4. In a liquefaction hazard assessment, which combination of factors most increases
susceptibility in a clean sand deposit?
A. High relative density and deep water table
B. Low plasticity index and high groundwater table
C. High fines content and low saturation
D. Well-graded gravel and shallow bedrock
Answer: B. Low plasticity index and high groundwater table
Rationale: Liquefaction susceptibility is highest in loose, clean sands with low plasticity
and shallow groundwater (B). High density (A) reduces risk, high fines (C) increases
resistance, and gravel (D) is generally not liquefiable.
Page 2 of 82
,5. A groundwater model calibrated to historic data predicts a steep cone of depression.
Which parameter is most critical to verify before using the model for long-term yield
analysis?
A. Specific yield of the confining layer
B. Hydraulic conductivity of the aquifer
C. Recharge rate from precipitation
D. Storativity of the aquifer
Answer: B. Hydraulic conductivity of the aquifer
Rationale: Hydraulic conductivity (B) controls the shape and extent of the cone of
depression. Specific yield (A) affects unconfined storage, recharge (C) influences long-term
budgets, and storativity (D) is key for transient storage but less critical for steady-state
drawdown shape.
6. Which California regulation specifically governs the cleanup of petroleum
hydrocarbons in soil and groundwater?
A. CERCLA
B. RCRA
C. California Code of Regulations Title 23, Division 3, Chapter 16
D. Clean Water Act
Answer: C. California Code of Regulations Title 23, Division 3, Chapter 16
Rationale: Title 23, CCR, Division 3, Chapter 16 (C) is the California UST cleanup
regulation. CERCLA (A) and RCRA (B) are federal, and the Clean Water Act (D) addresses
surface water quality, not underground storage tank cleanup.
Page 3 of 82
, 7. A seismic refraction survey shows a low-velocity layer beneath a high-velocity layer.
Which interpretation is most plausible?
A. A buried channel filled with saturated sediments
B. A velocity inversion indicating a fault zone
C. A normal sequence of consolidated rock
D. A shallow bedrock high
Answer: B. A velocity inversion indicating a fault zone
Rationale: A low-velocity layer beneath a high-velocity layer is a velocity inversion (B),
often caused by faulting or fracturing. Buried channels (A) typically show lower velocities
above higher ones, normal sequences (C) show increasing velocity with depth, and bedrock
highs (D) produce higher velocities.
8. In California, which agency has primary responsibility for reviewing and approving
geologic reports for subdivision projects under the Subdivision Map Act?
A. California Geological Survey
B. State Water Resources Control Board
C. County or city planning department
D. California Department of Fish and Wildlife
Answer: C. County or city planning department
Rationale: Local planning departments (C) review geologic reports for subdivisions under
the Subdivision Map Act. The California Geological Survey (A) provides technical input
but does not approve, the Water Board (B) handles water quality, and Fish and Wildlife (D)
addresses biological resources.
Page 4 of 82
