CALIFORNIA PROFESSIONAL GEOLOGIST (PG) EXAMINATION
ACTUAL COMPELETE 100 QUESTIONS AND CORRECT ANSWERS
WITH RATIONALES LATEST VERSION 2026-2027 (100%
VERIFIED ANSWERS) ALREADY GRADED A+
1. Which California state agency is responsible for administering the Professional Geologists
Act and issuing PG licenses?
A. California Environmental Protection Agency
B. Board for Professional Engineers, Land Surveyors, and Geologists
C. California Geological Survey
D. Department of Toxic Substances Control
Answer: B
Rationale: The Board for Professional Engineers, Land Surveyors, and Geologists (BPELSG) is
the regulatory authority that licenses and regulates geologists in California under the
Professional Geologists Act. The California Geological Survey is a scientific and mapping
agency, not a licensing board. The California EPA and DTSC deal with environmental
regulation but do not issue professional geology licenses.
2. The Alquist-Priolo Earthquake Fault Zoning Act primarily requires that:
A. All buildings within California be retrofitted for seismic safety.
B. A fault investigation be conducted and fault rupture hazard zones be defined prior to
development within designated zones.
C. Local governments prohibit construction in all areas of potential liquefaction.
D. Hazardous waste facilities must be at least 50 miles from active faults.
Answer: B
Rationale: The Alquist-Priolo Act requires delineation of Earthquake Fault Zones around active
faults and mandates that geologic investigations be performed to establish the location and
activity of fault traces before most new construction is permitted within those zones. It does
not mandate building retrofits statewide, nor does it regulate liquefaction (that is the Seismic
Hazards Mapping Act) or set distance limits for waste facilities.
3. According to the California Professional Geologists Act, which activity constitutes the
practice of professional geology?
A. Excavating soil samples under the supervision of a registered civil engineer
,B. Performing geological mapping and interpreting subsurface data to evaluate fault rupture
potential
C. Writing environmental impact reports without any geologic evaluation
D. Teaching introductory physical geology at a community college
Answer: B
Rationale: Professional geology includes the application of geologic principles to
investigations for public and private projects, such as evaluating fault rupture hazards.
Teaching and administrative tasks that do not impact public safety are generally exempt. A
technician excavating samples under direct responsible charge of a licensed professional may
not require a license themselves if not performing interpretive work.
4. A standard Unified Soil Classification System (USCS) symbol for a well-graded sand with silt
is:
A. GP
B. SW-SM
C. ML
D. GW
Answer: B
Rationale: SW-SM indicates a well-graded sand with silt, combining the symbol for well-
graded sand (SW) and silty sand (SM). GP is poorly graded gravel, ML is silt, and GW is well-
graded gravel. Understanding USCS symbols is fundamental for geotechnical logging and
report preparation.
5. During a groundwater sampling event, a geologist measures depth to water in a monitoring
well before purging. Which instrument is most appropriate for accurate measurement of
static water level?
A. Turbidity meter
B. Electronic water level indicator (tape)
C. pH/conductivity meter
D. Bailer
Answer: B
Rationale: An electronic water level indicator provides precise depth-to-water measurements
using a probe that signals upon contact with the water surface. A turbidity meter measures
water clarity, a pH/conductivity meter measures water quality parameters but not level, and
a bailer is used for sampling, not for initial static water level measurement.
6. What type of seismic wave has the highest velocity and is the first to arrive at a
seismograph station?
,A. S-wave
B. Love wave
C. Rayleigh wave
D. P-wave
Answer: D
Rationale: Primary (P) waves are compressional body waves that travel faster than secondary
(S) waves and surface waves (Love and Rayleigh). P-waves arrive first and are critical in
earthquake location and seismic refraction surveys. S-waves are slower shear waves, while
surface waves have even lower velocities.
7. A Phase I Environmental Site Assessment (ESA) conducted according to ASTM E1527
includes:
A. Drilling and sampling of soil and groundwater
B. A records review, site reconnaissance, and interviews to identify recognized environmental
conditions
C. Remediation of contaminated soil
D. Quantitative risk assessment
Answer: B
Rationale: A Phase I ESA is a non-intrusive study involving historical record review, site visit,
and interviews to identify potential contamination. Drilling and sampling are part of a Phase
II investigation. Remediation and quantitative risk assessment occur later in the site cleanup
process.
8. A contractor installs a groundwater monitoring well in a confined aquifer. The well screen is
placed entirely within the confined zone. When at rest, the water level in the well stabilizes
above the top of the aquifer. This water level represents the:
A. Hydraulic conductivity
B. Transmissivity
C. Potentiometric surface
D. Specific retention
Answer: C
Rationale: In a confined aquifer, the water level in a well rises above the confining bed,
indicating the potentiometric surface (the level to which water will rise). Hydraulic
conductivity and transmissivity are aquifer properties, not a water level. Specific retention is
the water held against gravity in unsaturated pores.
9. California’s Seismic Hazards Mapping Act requires the State Geologist to issue maps
identifying zones where which hazards are likely to occur?
, A. Tsunami inundation only
B. Liquefaction, earthquake-induced landslides, and strong ground shaking
C. Volcanic eruption
D. Coastal erosion
Answer: B
Rationale: The Seismic Hazards Mapping Act mandates the California Geological Survey to
delineate zones of required investigation for liquefaction and earthquake-induced landslides.
While shaking is a seismic hazard, the act focuses on secondary hazards requiring site-specific
investigation before permitting. Tsunami maps are produced under different authorities.
10. In rock mass classification, the Rock Quality Designation (RQD) is calculated based on:
A. The total core recovery percentage
B. The percentage of intact core pieces longer than 4 inches (100 mm)
C. The number of fractures per meter
D. The point load strength index
Answer: B
Rationale: RQD is determined by summing the lengths of all pieces of sound core longer than
100 mm (about 4 inches) and dividing by the total core run length, expressed as a percentage.
Total core recovery includes broken and weathered pieces, and RQD is a measure of rock mass
integrity, not just recovery.
11. A geologist is mapping the thickness of a mineralized vein that strikes N30°E and dips
45°SE on a slope that is parallel to the strike. The apparent width measured on the slope is 10
meters. What is the true thickness?
A. 10 m
B. 7.1 m
C. 14.1 m
D. 5 m
Answer: B
Rationale: When the slope face is parallel to the strike, the true thickness (t) = apparent width
× sin(dip). Here t = 10 m × sin(45°) = 10 × 0.707 ≈ 7.07 m. The 10 m is the slanted distance; 14.1
m would be larger, 5 m half would be incorrect trigonometric function.
12. Which California regulation specifically governs the cleanup of leaking underground
storage tanks (USTs)?
A. Porter-Cologne Water Quality Control Act
B. The Low-Threat UST Closure Policy and Health and Safety Code Chapter 6.7
ACTUAL COMPELETE 100 QUESTIONS AND CORRECT ANSWERS
WITH RATIONALES LATEST VERSION 2026-2027 (100%
VERIFIED ANSWERS) ALREADY GRADED A+
1. Which California state agency is responsible for administering the Professional Geologists
Act and issuing PG licenses?
A. California Environmental Protection Agency
B. Board for Professional Engineers, Land Surveyors, and Geologists
C. California Geological Survey
D. Department of Toxic Substances Control
Answer: B
Rationale: The Board for Professional Engineers, Land Surveyors, and Geologists (BPELSG) is
the regulatory authority that licenses and regulates geologists in California under the
Professional Geologists Act. The California Geological Survey is a scientific and mapping
agency, not a licensing board. The California EPA and DTSC deal with environmental
regulation but do not issue professional geology licenses.
2. The Alquist-Priolo Earthquake Fault Zoning Act primarily requires that:
A. All buildings within California be retrofitted for seismic safety.
B. A fault investigation be conducted and fault rupture hazard zones be defined prior to
development within designated zones.
C. Local governments prohibit construction in all areas of potential liquefaction.
D. Hazardous waste facilities must be at least 50 miles from active faults.
Answer: B
Rationale: The Alquist-Priolo Act requires delineation of Earthquake Fault Zones around active
faults and mandates that geologic investigations be performed to establish the location and
activity of fault traces before most new construction is permitted within those zones. It does
not mandate building retrofits statewide, nor does it regulate liquefaction (that is the Seismic
Hazards Mapping Act) or set distance limits for waste facilities.
3. According to the California Professional Geologists Act, which activity constitutes the
practice of professional geology?
A. Excavating soil samples under the supervision of a registered civil engineer
,B. Performing geological mapping and interpreting subsurface data to evaluate fault rupture
potential
C. Writing environmental impact reports without any geologic evaluation
D. Teaching introductory physical geology at a community college
Answer: B
Rationale: Professional geology includes the application of geologic principles to
investigations for public and private projects, such as evaluating fault rupture hazards.
Teaching and administrative tasks that do not impact public safety are generally exempt. A
technician excavating samples under direct responsible charge of a licensed professional may
not require a license themselves if not performing interpretive work.
4. A standard Unified Soil Classification System (USCS) symbol for a well-graded sand with silt
is:
A. GP
B. SW-SM
C. ML
D. GW
Answer: B
Rationale: SW-SM indicates a well-graded sand with silt, combining the symbol for well-
graded sand (SW) and silty sand (SM). GP is poorly graded gravel, ML is silt, and GW is well-
graded gravel. Understanding USCS symbols is fundamental for geotechnical logging and
report preparation.
5. During a groundwater sampling event, a geologist measures depth to water in a monitoring
well before purging. Which instrument is most appropriate for accurate measurement of
static water level?
A. Turbidity meter
B. Electronic water level indicator (tape)
C. pH/conductivity meter
D. Bailer
Answer: B
Rationale: An electronic water level indicator provides precise depth-to-water measurements
using a probe that signals upon contact with the water surface. A turbidity meter measures
water clarity, a pH/conductivity meter measures water quality parameters but not level, and
a bailer is used for sampling, not for initial static water level measurement.
6. What type of seismic wave has the highest velocity and is the first to arrive at a
seismograph station?
,A. S-wave
B. Love wave
C. Rayleigh wave
D. P-wave
Answer: D
Rationale: Primary (P) waves are compressional body waves that travel faster than secondary
(S) waves and surface waves (Love and Rayleigh). P-waves arrive first and are critical in
earthquake location and seismic refraction surveys. S-waves are slower shear waves, while
surface waves have even lower velocities.
7. A Phase I Environmental Site Assessment (ESA) conducted according to ASTM E1527
includes:
A. Drilling and sampling of soil and groundwater
B. A records review, site reconnaissance, and interviews to identify recognized environmental
conditions
C. Remediation of contaminated soil
D. Quantitative risk assessment
Answer: B
Rationale: A Phase I ESA is a non-intrusive study involving historical record review, site visit,
and interviews to identify potential contamination. Drilling and sampling are part of a Phase
II investigation. Remediation and quantitative risk assessment occur later in the site cleanup
process.
8. A contractor installs a groundwater monitoring well in a confined aquifer. The well screen is
placed entirely within the confined zone. When at rest, the water level in the well stabilizes
above the top of the aquifer. This water level represents the:
A. Hydraulic conductivity
B. Transmissivity
C. Potentiometric surface
D. Specific retention
Answer: C
Rationale: In a confined aquifer, the water level in a well rises above the confining bed,
indicating the potentiometric surface (the level to which water will rise). Hydraulic
conductivity and transmissivity are aquifer properties, not a water level. Specific retention is
the water held against gravity in unsaturated pores.
9. California’s Seismic Hazards Mapping Act requires the State Geologist to issue maps
identifying zones where which hazards are likely to occur?
, A. Tsunami inundation only
B. Liquefaction, earthquake-induced landslides, and strong ground shaking
C. Volcanic eruption
D. Coastal erosion
Answer: B
Rationale: The Seismic Hazards Mapping Act mandates the California Geological Survey to
delineate zones of required investigation for liquefaction and earthquake-induced landslides.
While shaking is a seismic hazard, the act focuses on secondary hazards requiring site-specific
investigation before permitting. Tsunami maps are produced under different authorities.
10. In rock mass classification, the Rock Quality Designation (RQD) is calculated based on:
A. The total core recovery percentage
B. The percentage of intact core pieces longer than 4 inches (100 mm)
C. The number of fractures per meter
D. The point load strength index
Answer: B
Rationale: RQD is determined by summing the lengths of all pieces of sound core longer than
100 mm (about 4 inches) and dividing by the total core run length, expressed as a percentage.
Total core recovery includes broken and weathered pieces, and RQD is a measure of rock mass
integrity, not just recovery.
11. A geologist is mapping the thickness of a mineralized vein that strikes N30°E and dips
45°SE on a slope that is parallel to the strike. The apparent width measured on the slope is 10
meters. What is the true thickness?
A. 10 m
B. 7.1 m
C. 14.1 m
D. 5 m
Answer: B
Rationale: When the slope face is parallel to the strike, the true thickness (t) = apparent width
× sin(dip). Here t = 10 m × sin(45°) = 10 × 0.707 ≈ 7.07 m. The 10 m is the slanted distance; 14.1
m would be larger, 5 m half would be incorrect trigonometric function.
12. Which California regulation specifically governs the cleanup of leaking underground
storage tanks (USTs)?
A. Porter-Cologne Water Quality Control Act
B. The Low-Threat UST Closure Policy and Health and Safety Code Chapter 6.7
