ASBOG 2021 Exam Review Practice Questions with Correct Answers| Latest Update
Guaranteed Success
What does it mean when you have topographic contours on a 1:24,000 scale base map that are
roughly circular and have hachures on the counters? They represent a closed depression
You have a base map at a scale of 1:6,000 and you need to represent the information you
obtained during a field investigation of a site that is one square mile, that included mapping of
your site as well as subsurface exploration results. What do you need to do to the map to make
it work? Use a larger scale map because it covers a smaller area
If you have a map that is at a scale of 1:24,000 and you want to draw a cross section with a 10
times exaggeration, what will the vertical scale be? 1" = 200'
What is the approximate exaggerated dip if the vertical scale is exaggerated 10 times and the
true dip is 30*? 80*
What do you do if you have forgotten to research the current magnetic declination before you
go to the field to investigate and map a site for a geologic mapping project? Align your map
with two planimetric features and measure the declination with your compasss.
Location and elevation input into your GIS program comes from your GPS system. The maps
generated by this system are based on a reference datum. If the maps were created in 1972,
what do you need to do to use them with the data output from your GPS system? Make the
conversion from NAD27 to NAD83.
For a strike and dip of N25*E, 15*N, what is the attitude of the bed in terms of the azimuth?
205, 15
MAP NEEDED PAGE 3: What is the strike and dip of the bed? N70*W, 38*NE
,MAP NEEDED PAGE 3: What apparent dip would you expect to find along a trench that is
perpendicular to cross section A-A'? 26*
The top of Unit A is found at location X at the ground surface and is dipping 40* to the west.
The slope is 20* to the east. Unit B is 75 feet thick, is conformable with and below Unit A. The
slope distance from the outcrop at the top of Unit A at location X to the outcrop of the top of
Unit B is 173 feet. Unit B is a unit where you would expect a lot of lost circulation when drilling.
The top of unit B is found at a depth of 195 feet. What is the thickness of Unit A? 150 feet
MAP NEEDED PAGE 4: What geologic law is used to determine the relative ages of the faults?
Law of Cross-Cutting relationships
MAP NEEDED PAGE 4: There is a synclinal axis downslope of Unit B. Which direction is the slope
facing? Is it steep?. NW and moderately sloping
MAP NEEDED PAGE 4: What is the youngest continuously deposited bed found on the map?
Unit D
MAP NEEDED PAGE 4: What type of feature would you expect to see on this map if you had a
plunging anticline? Closure of the units with the plunge in the direction of closure
MAP NEEDED PAGE 4: What evidence do you have to determine weather the eastern fault is
normal, reverse or strike-slip? Normal east side down because when projected in a cross
section Unit A on the west side is higher than its counterpart on the east side.
MAP NEEDED PAGE 4: If unit A is Permian, what is the most likely age of unit D? Cretaceous
Which of the following survey corrections are required for the given geophysical survey
method? Gravity Survey - Bouguer anomaly
, When investigating an active fault that is relatively close to the surface to determine the impact
if would have on a planned structure, it is important to locate it precisely and determine the
recency of activity. In order to accomplish this which of the following field methods would be
the most appropriate? seismic refraction and trenching
E-LOG ON PG-6: What is the distinguishing feature that would indicate the presence of the fresh
water-salt water interface in this coastal aquifer? A change in the resistivity in Unit D with
little corresponding change in the SP log
E-LOG ON PG-6: Where would you install the perforated section in this water supply well?
620 to 640
When flying to obtain air photos, the flight lines have to be relatively short before they double
back on themselves. Why is this? If the flight lines are too long they become less parallel
with length making it difficult to line up the photographs to make them be able to be viewed in
stereo.
Which remote sensing method would be the most appropriate for the monitoring of minor
ground movements in terrain that has many small landslides LIDAR (light detection and
ranging)
You are getting ready to undertake an investigation into fault hazards in an urban area. Since
this is an urban area you cannot fly any lower than 1000 feet above the ground surface. The
amount of relief exposed at the site is up to 900 feet of elevation gain. In order to get stereo-
paired aerial photographs at a usable scale for the investigation you need to have a photo scale
of 1:2400. Which focal length and flying height makes the most sense? 12 inch focal length
at a flying height of 2400 feet above the ground
What is the most important reasons why rotary methods are NOT often used in hydrogeological
investigations? Because the drilling fluids interfere with the water quality.
Direct push methods are a relatively inexpensive way to collect what? Penetration
resistance, pore water pressures, radioactive characteristics of the soil
Guaranteed Success
What does it mean when you have topographic contours on a 1:24,000 scale base map that are
roughly circular and have hachures on the counters? They represent a closed depression
You have a base map at a scale of 1:6,000 and you need to represent the information you
obtained during a field investigation of a site that is one square mile, that included mapping of
your site as well as subsurface exploration results. What do you need to do to the map to make
it work? Use a larger scale map because it covers a smaller area
If you have a map that is at a scale of 1:24,000 and you want to draw a cross section with a 10
times exaggeration, what will the vertical scale be? 1" = 200'
What is the approximate exaggerated dip if the vertical scale is exaggerated 10 times and the
true dip is 30*? 80*
What do you do if you have forgotten to research the current magnetic declination before you
go to the field to investigate and map a site for a geologic mapping project? Align your map
with two planimetric features and measure the declination with your compasss.
Location and elevation input into your GIS program comes from your GPS system. The maps
generated by this system are based on a reference datum. If the maps were created in 1972,
what do you need to do to use them with the data output from your GPS system? Make the
conversion from NAD27 to NAD83.
For a strike and dip of N25*E, 15*N, what is the attitude of the bed in terms of the azimuth?
205, 15
MAP NEEDED PAGE 3: What is the strike and dip of the bed? N70*W, 38*NE
,MAP NEEDED PAGE 3: What apparent dip would you expect to find along a trench that is
perpendicular to cross section A-A'? 26*
The top of Unit A is found at location X at the ground surface and is dipping 40* to the west.
The slope is 20* to the east. Unit B is 75 feet thick, is conformable with and below Unit A. The
slope distance from the outcrop at the top of Unit A at location X to the outcrop of the top of
Unit B is 173 feet. Unit B is a unit where you would expect a lot of lost circulation when drilling.
The top of unit B is found at a depth of 195 feet. What is the thickness of Unit A? 150 feet
MAP NEEDED PAGE 4: What geologic law is used to determine the relative ages of the faults?
Law of Cross-Cutting relationships
MAP NEEDED PAGE 4: There is a synclinal axis downslope of Unit B. Which direction is the slope
facing? Is it steep?. NW and moderately sloping
MAP NEEDED PAGE 4: What is the youngest continuously deposited bed found on the map?
Unit D
MAP NEEDED PAGE 4: What type of feature would you expect to see on this map if you had a
plunging anticline? Closure of the units with the plunge in the direction of closure
MAP NEEDED PAGE 4: What evidence do you have to determine weather the eastern fault is
normal, reverse or strike-slip? Normal east side down because when projected in a cross
section Unit A on the west side is higher than its counterpart on the east side.
MAP NEEDED PAGE 4: If unit A is Permian, what is the most likely age of unit D? Cretaceous
Which of the following survey corrections are required for the given geophysical survey
method? Gravity Survey - Bouguer anomaly
, When investigating an active fault that is relatively close to the surface to determine the impact
if would have on a planned structure, it is important to locate it precisely and determine the
recency of activity. In order to accomplish this which of the following field methods would be
the most appropriate? seismic refraction and trenching
E-LOG ON PG-6: What is the distinguishing feature that would indicate the presence of the fresh
water-salt water interface in this coastal aquifer? A change in the resistivity in Unit D with
little corresponding change in the SP log
E-LOG ON PG-6: Where would you install the perforated section in this water supply well?
620 to 640
When flying to obtain air photos, the flight lines have to be relatively short before they double
back on themselves. Why is this? If the flight lines are too long they become less parallel
with length making it difficult to line up the photographs to make them be able to be viewed in
stereo.
Which remote sensing method would be the most appropriate for the monitoring of minor
ground movements in terrain that has many small landslides LIDAR (light detection and
ranging)
You are getting ready to undertake an investigation into fault hazards in an urban area. Since
this is an urban area you cannot fly any lower than 1000 feet above the ground surface. The
amount of relief exposed at the site is up to 900 feet of elevation gain. In order to get stereo-
paired aerial photographs at a usable scale for the investigation you need to have a photo scale
of 1:2400. Which focal length and flying height makes the most sense? 12 inch focal length
at a flying height of 2400 feet above the ground
What is the most important reasons why rotary methods are NOT often used in hydrogeological
investigations? Because the drilling fluids interfere with the water quality.
Direct push methods are a relatively inexpensive way to collect what? Penetration
resistance, pore water pressures, radioactive characteristics of the soil
