Section_J_Attachment_6c_2022_CAVE_Geophysical_Investigative_Report.pdf
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- Attached to
- CAVE 332397 ¿ Replace Main Distribution System Federal contract opportunity
- Solicitation number
- 140P2026R0007
About this file
This document is an appendix from a Geophysical Investigative Report for Cave Geophysical Survey Services conducted at Carlsbad Caverns National Park in New Mexico. The report contains detailed geophysical survey data for four different survey areas (Areas 1-4), utilizing multiple geophysical techniques including Ground Penetrating Radar (GPR), Frequency Domain Electromagnetic (FDEM) methods, and Electrical Resistivity Tomography (ERT). The survey aims to investigate potential karst features, subsurface conditions, and underground geological structures.
The geophysical investigations employed multiple scanning techniques across different survey lines, looking for anomalies that could indicate fractured rock, vugs (small cavities), potential voids, and karst-related features. The survey identified various subsurface anomalies with different potential significance, ranging from minor features like small-scale voids to more significant karst features with open, interconnected fractures. The report includes detailed color-coded maps and cross-sectional images showing resistivity, conductivity, and GPR signal interpretations, with notations about potential subsurface utilities and geological characteristics at depths ranging from near-surface to approximately 27 feet below ground surface.
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Text version
November 2022Checked by: D. LaymonDrafted by: R. Bowling
Project #: 22-182
National Park Service
GPR Example Scanlines Area 1 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
Negative Positive
Interpreted Minor GPR Anomaly
- indicates fractured rock, vugs, possibly small-scale voids
Interpreted Significant GPR Anomaly
- indicates more significant karst features. Open, interconected fractures and larger scale voids
Note: Depths are based on a 1D time-to-depth conversion of GPR traveltimes using an estimated bulk GPR velocity of 0.299 ft/ns (0.091 m/ns)
20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 Scanline Distance (ft)
GPR Scanline 0546
Tw o-
W ay
T ra ve lti m e
(n s)
3.0
6.0
12.0
15.0
9.0
D ep th (f t b gs
W E
18.0
21.0
GPR Signal
0102030 Scanline Distance (ft)
GPR Scanline 0515
Tw o-
W ay
T ra ve lti m e
(n s)
24.0
27.0
3.0
6.0
12.0
15.0
9.0
D ep th (f t b gs
E
18.0
21.0
24.0
27.0 507100 507200 507300 507400 507500 507600 507700 507800 507900 508000 508100 508200
Easting (ftUS)
N or th in g (ft
U S)
W
Clean Singlular Diffraction
- Likley due to exisiting subsurface utillity
Scanline 0515
Scanline 0546
Figure B-2
CRS: New Mexico East (ftUS)
November 2022Checked by: R. BowlingDrafted by: N. Pendrigh
National Park Service
FDEM Results: Area 1, Coil 1 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
507000 507100 507200 507300 507400 507500 507600 507700 507800 507900 508000 508100 508200 508300 508400 508500 508600 508700 508800 Easting (ftUS)
507000 507100 507200 507300 507400 507500 507600 507700 507800 507900 508000 508100 508200 508300 508400 508500 508600 508700 508800
FDEM Coil 1 Conductivity (1.48 m coil separation)
N or th in g (ft
U S)
Area of interference from surface or subsurface infrastructure
0 2 4 6 8 10 12 14 16 18 20
Apparent Conductivity (mS/m)
CRS: New Mexico East (ftUS)
Contour Data: USGS 3DEP, index contour interval 10 ft
0 100 200 300 400
Map Scale (ftUS)
Figure B-3
Anomalous low apparent conductivity
- may be caused by fractured rock, vugs, and possible near-surface voiding.
Increased potential for karst
Subsurface Utillities As of 11/2020 (APWA Color Codes)
- White highlighted lines are proposed new
National Park Service
FDEM Results: Area 1, Coil 2 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
507000 507100 507200 507300 507400 507500 507600 507700 507800 507900 508000 508100 508200 508300 508400 508500 508600 508700 508800 Easting (ftUS)
507000 507100 507200 507300 507400 507500 507600 507700 507800 507900 508000 508100 508200 508300 508400 508500 508600 508700 508800
FDEM Coil 2 Conductivity (2.82 m coil separation)
N or th in g (ft
U S)
Area of interference from surface or subsurface infrastructure
0 2 4 6 8 10 12 14 16 18 20
Apparent Conductivity (mS/m)
CRS: New Mexico East (ftUS)
Contour Data: USGS 3DEP, index contour interval 10 ft
0 100 200 300 400
Map Scale (ftUS)
Figure B-4
Anomalous low apparent conductivity
- may be caused by fractured rock, vugs, and possible near-surface voiding.
Increased potential for karst
Subsurface Utillities As of 11/2020 (APWA Color Codes)
National Park Service
FDEM Results: Area 1, Coil 3 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
507000 507100 507200 507300 507400 507500 507600 507700 507800 507900 508000 508100 508200 508300 508400 508500 508600 508700 508800 Easting (ftUS)
507000 507100 507200 507300 507400 507500 507600 507700 507800 507900 508000 508100 508200 508300 508400 508500 508600 508700 508800
FDEM Coil 3 Conductivity (4.49 m coil separation)
N or th in g (ft
U S)
Area of interference from surface or subsurface infrastructure
0 2 4 6 8 10 12 14 16 18 20
Apparent Conductivity (mS/m)
CRS: New Mexico East (ftUS)
Contour Data: USGS 3DEP, index contour interval 10 ft
0 100 200 300 400
Map Scale (ftUS)
Figure B-5
Anomalous low apparent conductivity
- may be caused by fractured rock, vugs, and possible near-surface voiding.
Increased potential for karst
Subsurface Utillities As of 11/2020 (APWA Color Codes)
November 2022Checked by: R. BowlingDrafted by: D. Trekas
National Park Service
ERT Anomalies Area 1 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
ERT Line < = 20 ft.
>20 - >50 ft.
Interpreted Major ERT Anomaly >30,000 ohm-m
507000 507100 507200 507300 507400 507500 507600 507700 507800 507900 508000 508100 508200 508300 508400 508500 508600 508700 508800 Easting (ftUS)
507000 507100 507200 507300 507400 507500 507600 507700 507800 507900 508000 508100 508200 508300 508400 508500 508600 508700 508800
N or th in g (ft
U S)
CRS: New Mexico East (ftUS)
Contour Data: USGS 3DEP, index contour interval 10 ft
0 100 200 300 400
Map Scale (ftUS)
Figure B-6
< = 20 ft.
>20 - >50 ft.
Interpreted High ERT Anomaly >10,000 ohm-m
< = 20 ft.
>20 - >50 ft.
Interpreted Low ERT Anomaly <50 ohm-m Subsurface Utillities
As of 11/2020 (APWA Color Codes)
- White highlighted lines are proposed new
Line 15 Line 14Line 13Line 12
Line 10
Line 11
Line 9
Line 8.2
Line 8
Line 7
Line 6
Line 5
Line 4Line 3
Line 2 Line 1
Likely interference occurring from multiple subsurface utilties in this area
10001000
10000
0 20 40 60 80 100 120 140 160 180 200 220 Line Distance (ft)
Area 1 Line 15
El ev at io n (ft
N S
0 20 40 60 80 100 120 140 160 180 200 220 240 Line Distance (ft)
Area 1 Line 14
El ev at io n (ft
N S
00 1000
0 20 40 60 80 100 120 140 160 180 200 220 240 260 Line Distance (ft)
Area 1 Line 13
El ev at io n (ft
N S
10 30 50 70 90 200 10000 30000 50000
Apparent Resistivity (Ohm-m)
00 1000
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 Line Distance (ft)
Area 1 Line 12
El ev at io n (ft
N S
0 20 40 60 80 100 120 140 160 Line Distance (ft)
Area 1 Line 2
El ev at io n (ft
N S
0 20 40 60 80 100 120 140 160 180 Line Distance (ft)
Area 1 Line 1
El ev at io n (ft
N S
Notes:
- Anomalous highly resistive zones (>30,000 ohm-m) may represent areas of either extremely competent limestone or potential air-filled karst features such as vugs, fractures, and voids. - High potential for karst
- High resistivity zones (>10,000 ohm-m) may represent competent limestone or air-filled karst features such as vugs, fractures, or voids. - Medium potential for karst
- Low resistivity zones (<50 ohm-m) may represent areas of highly weathered limestone, shale, or potential karst-related clay-filled solution zones.
- Some areas have extremely high contact resistance due to local soil and bedrock conditions. This may introduce noise to the data affecting models and interpretations.
November 2022Checked by: D. LaymonDrafted by: D. Trekas
Project #: 22-182
National Park Service
ERT Area 1: Lines 1 & 2, 12-14 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
507000 507200 507400 507600 507800 508000 508200 508400 508600 508800 Easting (ftUS)
N or th in g
(ft U s)
Line 1 Line 2
Line 12 Line 13 Line 14
Line 15
Figure B-7
November 2022Checked by: D. LaymonDrafted by: D. Trekas
National Park Service
ERT Area 1: Lines 3-5 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
1000 1000 10000
020406080100120140160180200220 Line Distance (ft)
Area 1 Line 3
El ev at io n (ft
1000 1000 1000
10000
100001000010000
10000
10000
020406080100120140160180200220240260280300320340360380400420440460 Line Distance (ft)
Area 1 Line 4
El ev at io n (ft
10000
10000
10000
10000
10000
020406080100120140160180200220240260280300320340360380400420440460480500 Line Distance (ft)
Area 1 Line 5
El ev at io n (ft
10 30 50 70 90 200 10000 30000 50000
Apparent Resistivity (Ohm-m)
E W
EW
EW
Notes:
- Anomalous highly resistive zones (>30,000 ohm-m) may represent areas of either extremely competent limestone or potential air-filled karst features such as vugs, fractures, and voids. - High potential for karst
- High resistivity zones (>10,000 ohm-m) may represent competent limestone or air-filled karst features such as vugs, fractures, or voids. - Medium potential for karst
- Low resistivity zones (<50 ohm-m) may represent areas of highly weathered limestone, shale, or potential karst-related clay-filled solution zones.
- Some areas have extremely high contact resistance due to local soil and bedrock conditions. This may introduce noise to the data affecting models and interpretations.
Figure B-8
507000 507200 507400 507600 507800 508000 508200 508400 508600 508800 Easting (ftUS)
N or th in g
(ft U s)
Line 3
Line 4 Line 5
100010001000
00 1000
0 40 80 120 160 200 240 280 320 360 400 440 480 520 560 600 640 680 720 760 800 840 880 920 960 Line Distance (ft)
Area 1 Line 11
El ev at io n (ft
EW
10 30 50 70 90 200 10000 30000 50000
Apparent Resistivity (Ohm-m)
0 40 80 120 160 200 240 280 320 360 400 440 Line Distance (ft)
Area 1 Line 9
El ev at io n (ft
EW
0 40 80 120 160 200 240 280 320 360 Line Distance (ft)
Area 1 Line 8
El ev at io n (ft
EW
0 40 80 120 160 200 240 280 320 360 400 Line Distance (ft)
Area 1 Line 8.2
El ev at io n (ft
EW
0 40 80 120 160 200 240 280 320 360 400 440 480 Line Distance (ft)
Area 1 Line 7
El ev at io n (ft
EW
0 40 80 120 160 200 240 280 Line Distance (ft)
Area 1 Line 6
El ev at io n (ft
) W E
Notes:
- Anomalous highly resistive zones (>30,000 ohm-m) may represent areas of either extremely competent limestone or potential air-filled karst features such as vugs, fractures, and voids. - High potential for karst
- High resistivity zones (>10,000 ohm-m) may represent competent limestone or air-filled karst features such as vugs, fractures, or voids. - Medium potential for karst
- Low resistivity zones (<50 ohm-m) may represent areas of highly weathered limestone, shale, or potential karst-related clay-filled solution zones.
- Some areas have extremely high contact resistance due to local soil and bedrock conditions. This may introduce noise to the data affecting models and interpretations.
November 2022Checked by: D. LaymonDrafted by: D. Trekas
Project #: 22-182
National Park Service
ERT Area 1: Lines 6-11 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
507000 507200 507400 507600 507800 508000 508200 508400 508600 508800 Easting (ftUS)
N or th in g
(ft U s)
Line 6
Line 11
0 40 80 120 160 200 240 280 320 360 400 Line Distance (ft)
Area 1 Line 10
El ev at io n (ft
EW
Line 8
Line 9
Line 7
Line 8.2 Line 10
Figure B-9
Geophysical Investigative Report: Cave Geophysical Survey Services, Carlsbad Caverns National Park, Carlsbad, NM Contract: 140P1322P0045P
APPENDIX B, AREA 2
National Park Service
GPR Anomalies Area 2 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
506900 506950 507000 507050 507100 507150 507200 507250 507300 507350 507400 507450 507500 507550 507600 507650 507700 507750 507800 507850 507900 Easting (ftUS)
506900 506950 507000 507050 507100 507150 507200 507250 507300 507350 507400 507450 507500 507550 507600 507650 507700 507750 507800 507850 507900
N or th in g
(ft U
S)
Interpreted Significant GPR Anomaly (depth ft bgs)
< = 3 < = 6
< = 9 < = 12
< = 15 > 15
Interpreted Minor GPR Anomaly (depth ft bgs)
< = 3 < = 6
< = 9 < = 12
< = 15 > 15
GPR Scanline
CRS: New Mexico East (ftUS)
Contour Data: USGS 3DEP, index contour interval 10 ft
0 50 100 150 200
Map Scale (ftUS)
Subsurface Utillities As of 11/2020 (APWA Color Codes) are proposed new Figure B-10
National Park Service
GPR Example Scanlines Area 2 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
Negative Positive
Interpreted Minor GPR Anomaly
- indicates fractured rock, vugs, possibly small-scale voids
Interpreted Significant GPR Anomaly
- indicates more significant karst features. Open, interconected fractures and larger scale voids
Note: Depths are based on a 1D time-to-depth conversion of GPR traveltimes using an estimated bulk GPR velocity of 0.299 ft/ns (0.091 m/ns)
102030405060 Scanline Distance (ft)
GPR Scanline 0436
Tw o-
W ay
T ra ve lti m e
(n s)
3.0
6.0
12.0
15.0
9.0
D ep th (f t b gs
W E
18.0
21.0
240250260270280290300310320330340 Scanline Distance (ft)
GPR Scanline 0403
Tw o-
W ay
T ra ve lti m e
(n s)
24.0
27.0
3.0
6.0
12.0
15.0
9.0
D ep th (f t b gs
E
18.0
21.0
24.0
27.0
W
Clean Singlular Diffraction
- Likley due to exisiting subsurface utillity
506900 507000 507100 507200 507300 507400 507500 507600 507700 507800 507900 Easting (ftUS)
N or th in g (ft
U S)
GPR Signal
Anomaly may be associated with utility trench
Anomaly may be associated with utility trench
CRS: New Mexico East (ftUS)
Scanline 0436
Anomaly may be associated with utility trench
Scanline 0403
Figure B-11
National Park Service
FDEM Results: Area 2, Coil 1 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
506900 506975 507050 507125 507200 507275 507350 507425 507500 507575 507650 507725 507800 507875 Easting (ftUS)
506900 506975 507050 507125 507200 507275 507350 507425 507500 507575 507650 507725 507800 507875
FDEM Coil 1 Conductivity (1.48 m coil separation)
N or th in g
(ft U
S)
CRS: New Mexico East (ftUS)
Contour Data: USGS 3DEP, index contour interval 10 ft
0 50 100 150 200
Map Scale (ftUS)
Area of interference from surface or subsurface infrastructure
Anomalous low apparent conductivity
- may be caused by fractured rock, vugs, and possible near-surface voiding.
Increased potential for karst
Subsurface Utillities As of 11/2020 (APWA Color Codes)
- White highlighted lines are proposed new
0 2 4 6 8 10 12 14 16 18 20
Apparent Conductivity (mS/m)
Figure B-12
National Park Service
FDEM Results: Area 2, Coil 2 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
506900 506975 507050 507125 507200 507275 507350 507425 507500 507575 507650 507725 507800 507875 Easting (ftUS)
506900 506975 507050 507125 507200 507275 507350 507425 507500 507575 507650 507725 507800 507875
FDEM Coil 2 Conductivity (2.82 m coil separation)
N or th in g
(ft U
S)
CRS: New Mexico East (ftUS)
Contour Data: USGS 3DEP, index contour interval 10 ft
0 50 100 150 200
Map Scale (ftUS)
Area of interference from surface or subsurface infrastructure
Anomalous low apparent conductivity
- may be caused by fractured rock, vugs, and possible near-surface voiding.
Increased potential for karst
Subsurface Utillities As of 11/2020 (APWA Color Codes)
- White highlighted lines are proposed new
0 2 4 6 8 10 12 14 16 18 20
Figure B-13
National Park Service
FDEM Results: Area 2, Coil 3 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
506900 506975 507050 507125 507200 507275 507350 507425 507500 507575 507650 507725 507800 507875 Easting (ftUS)
506900 506975 507050 507125 507200 507275 507350 507425 507500 507575 507650 507725 507800 507875
FDEM Coil 3 Conductivity (4.49m coil separation)
N or th in g
(ft U
S)
CRS: New Mexico East (ftUS)
Contour Data: USGS 3DEP, index contour interval 10 ft
0 50 100 150 200
Map Scale (ftUS)
Area of interference from surface or subsurface infrastructure
Anomalous low apparent conductivity
- may be caused by fractured rock, vugs, and possible near-surface voiding.
Increased potential for karst
Subsurface Utillities As of 11/2020 (APWA Color Codes)
- White highlighted lines are proposed new
0 2 4 6 8 10 12 14 16 18 20
Figure B-14
November 2022Checked by: R. BowlingDrafted by: D. Trekas
National Park Service
ERT Anomalies Area 2 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
506950 507000 507050 507100 507150 507200 507250 507300 507350 507400 507450 507500 507550 507600 507650 507700 507750 507800 Easting (ftUS)
506950 507000 507050 507100 507150 507200 507250 507300 507350 507400 507450 507500 507550 507600 507650 507700 507750 507800
N or th in g
(ft U
S)
ERT Line < = 20 ft.
>20 - >50 ft.
Interpreted Major ERT Anomaly >30,000 ohm-m
< = 20 ft.
>20 - >50 ft.
Interpreted High ERT Anomaly >10,000 ohm-m
< = 20 ft.
>20 - >50 ft.
Interpreted Low ERT Anomaly <50 ohm-m Subsurface Utillities
As of 11/2020 (APWA Color Codes)
- White highlighted lines are proposed new
CRS: New Mexico East (ftUS)
Contour Data: USGS 3DEP, index contour interval 10 ft
0 50 100 150 200
Map Scale (ftUS)
Figure B-15
Line 14
Line 13
Line 12
Line 11
Line 10
Line 9
Line 8
Line 7
Line 6
Line 5
Line 4
Line 3 Line 2
Line 1
00 1000
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 Line Distance (ft)
Area 2 Line 5
El ev at io n (ft
W E
10 30 50 70 90 200 10000 30000 50000
Apparent Resistivity (Ohm-m)
10001000
0 20 40 60 80 100 120 140 160 180 200 Line Distance (ft)
Area 2 Line 4
El ev at io n (ft
W E
020406080100120 Line Distance (ft)
Area 2 Line 3
El ev at io n (ft
W E
10 30 50 70 90 110 130 150 170 190 Line Distance (ft)
Area 2 Line 2
El ev at io n (ft
W E
100 1000
0 20 40 60 80 100 120 140 160 180 200 Line Distance (ft)
Area 2 Line 1
El ev at io n (ft
W E
Notes:
- Anomalous highly resistive zones (>30,000 ohm-m) may represent areas of either extremely competent limestone or potential air-filled karst features such as vugs, fractures, and voids. - High potential for karst
- High resistivity zones (>10,000 ohm-m) may represent competent limestone or air-filled karst features such as vugs, fractures, or voids. - Medium potential for karst
- Low resistivity zones (<50 ohm-m) may represent areas of highly weathered limestone, shale, or potential karst-related clay-filled solution zones.
- Some areas have extremely high contact resistance due to local soil and bedrock conditions. This may introduce noise to the data affecting models and interpretations.
November 2022Checked by: D. LaymonDrafted by: D. Trekas
Project #: 22-182
National Park Service
ERT Area 2: Lines 1-5 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
506900 507100 507300 507500 507700 Easting (ftUS)
N or th in g
(ft U
S)
Figure B-16
Line 1 Line 4
Line 5
Line 3
10000
10000
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 Line Distance (ft)
Area 2 Line 8
El ev at io n (ft
00 1000 10000
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 Line Distance (ft)
Area 2 Line 7
El ev at io n (ft
1000 1000
100010001000
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 Line Distance (ft)
Area 2 Line 6
El ev at io n (ft
Notes:
- Anomalous highly resistive zones (>30,000 ohm-m) may represent areas of either extremely competent limestone or potential air-filled karst features such as vugs, fractures, and voids. - High potential for karst
- High resistivity zones (>10,000 ohm-m) may represent competent limestone or air-filled karst features such as vugs, fractures, or voids. - Medium potential for karst
- Low resistivity zones (<50 ohm-m) may represent areas of highly weathered limestone, shale, or potential karst-related clay-filled solution zones.
- Some areas have extremely high contact resistance due to local soil and bedrock conditions. This may introduce noise to the data affecting models and interpretations.
10 30 50 70 90 200 10000 30000 50000
Apparent Resistivity (Ohm-m)
W
W
W
E
E
E
November 2022Checked by: D. LaymonDrafted by: D. Trekas
Project #: 22-182
National Park Service
ERT Area 2: Lines 6-8 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
506900 507100 507300 507500 507700 Easting (ftUS)
N or th in g
(ft U
S)
Line 6
Figure B-17
Line 7
Line 8
0 20 40 60 80 100 120 140 160 180 Line Distance (ft)
Area 2 Line 14
El ev at io n (ft
0 20 40 60 80 100 120 140 160 180 200 220 Line Distance (ft)
Area 2 Line 13
El ev at io n (ft
10001000
10001000
0 20 40 60 80 100 120 140 160 180 200 220 240 Line Distance (ft)
Area 2 Line 9
El ev at io n (ft
Notes:
- Anomalous highly resistive zones (>30,000 ohm-m) may represent areas of either extremely competent limestone or potential air-filled karst features such as vugs, fractures, and voids. - High potential for karst
- High resistivity zones (>10,000 ohm-m) may represent competent limestone or air-filled karst features such as vugs, fractures, or voids. - Medium potential for karst
- Low resistivity zones (<50 ohm-m) may represent areas of highly weathered limestone, shale, or potential karst-related clay-filled solution zones.
- Some areas have extremely high contact resistance due to local soil and bedrock conditions. This may introduce noise to the data affecting models and interpretations.
W E
W E
W E
10 30 50 70 90 200 10000 30000 50000
Apparent Resistivity (Ohm-m)
November 2022Checked by: D. LaymonDrafted by: D. Trekas
Project #: 22-182
National Park Service
ERT Area 2: Lines 9, 13 &14 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
506900 507100 507300 507500 507700 Easting (ftUS)
N or th in g
(ft U
S)
Figure B-18
Line 9
Line 13 Line 14
0 50 100 150 200 250 300 350 400 450 500 Line Distance (ft)
Area 2 Line 12
El ev at io n (ft
0 50 100 150 200 250 300 350 400 450 500 Line Distance (ft)
Area 2 Line 11
El ev at io n (ft
10000
0 50 100 150 200 250 300 350 400 450 500 550 600 650 Line Distance (ft)
Area 2 Line 10
El ev at io n (ft
Notes:
- Anomalous highly resistive zones (>30,000 ohm-m) may represent areas of either extremely competent limestone or potential air-filled karst features such as vugs, fractures, and voids. - High potential for karst
- High resistivity zones (>10,000 ohm-m) may represent competent limestone or air-filled karst features such as vugs, fractures, or voids. - Medium potential for karst
- Low resistivity zones (<50 ohm-m) may represent areas of highly weathered limestone, shale, or potential karst-related clay-filled solution zones.
- Some areas have extremely high contact resistance due to local soil and bedrock conditions. This may introduce noise to the data affecting models and interpretations.
10 30 50 70 90 200 10000 30000 50000
Apparent Resistivity (Ohm-m)
W E
W E
W E
November 2022Checked by: D. LaymonDrafted by: D. Trekas
Project #: 22-182
National Park Service
ERT Area 2: Lines 10-12 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
506900 507100 507300 507500 507700 Easting (ftUS)
N or th in g
(ft U
S) Line 10
Line 11 Line 12
Figure B-19
Geophysical Investigative Report: Cave Geophysical Survey Services, Carlsbad Caverns National Park, Carlsbad, NM
APPENDIX B, AREA 3
National Park Service
GPR Anomalies Area 3 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
506200 506300 506400 506500 506600 506700 506800 506900 507000 507100 507200 Easting (ftUS)
506200 506300 506400 506500 506600 506700 506800 506900 507000 507100 507200
N or th in g
(ft U
S)
Interpreted Significant GPR Anomaly (depth ft bgs)
< = 3 < = 6
< = 9 < = 12
< = 15 > 15
Interpreted Minor GPR Anomaly (depth ft bgs)
< = 3 < = 6
< = 9 < = 12
< = 15 > 15
GPR Scanline
CRS: New Mexico East (ftUS)
Contour Data: USGS 3DEP, index contour interval 10 ft
0 50 100 150 200
Map Scale (ftUS)
Subsurface Utillities As of 11/2020 (APWA Color Codes)
- White highlighted lines are proposed new Figure B-20
GPR response likely associated roadway embankment fill
National Park Service
GPR Example Scanlines Area 3 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
506200 506350 506500 506650 506800 506950 507100 Easting (ftUS)
N or th in g (ft
U S)
CRS: New Mexico East (ftUS)
Negative Positive
Interpreted Minor GPR Anomaly
- indicates fractured rock, vugs, possibly small-scale voids
Interpreted Significant GPR Anomaly
- indicates more significant karst features. Open, interconected fractures and larger scale voids
Note: Depths are based on a 1D time-to-depth conversion of GPR traveltimes using an estimated bulk GPR velocity of 0.299 ft/ns (0.091 m/ns)
Scanline 0284
Scanline 0220
530540550560570580590600610620630640650660670680 Scanline Distance (ft)
GPR Scanline 0220
Tw o-
W ay
T ra ve lti m e
(n s)
3.0
6.0
12.0
15.0
9.0
D ep th (f t b gs
SW NE
18.0
21.0
GPR Signal
120 130 140 150 160 170 180 190 200 210 220 230 240 Scanline Distance (ft)
GPR Scanline 0284
Tw o-
W ay
T ra ve lti m e
(n s)
24.0
27.0
3.0
6.0
12.0
15.0
9.0
D ep th (f t b gs
E
18.0
21.0
24.0
27.0
W
Figure B-21
November 2022Checked by: R. BowlingDrafted by: K. Marberry
National Park Service
FDEM Results: Area 3, Coil 1 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
506200 506300 506400 506500 506600 506700 506800 506900 507000 507100 507200 507300 Easting (ftUS)
506200 506300 506400 506500 506600 506700 506800 506900 507000 507100 507200 507300
FDEM Coil 1 Conductivity (1.48 m coil separation)
N or th in g
(ft U
S)
CRS: New Mexico East (ftUS)
Contour Data: USGS 3DEP, index contour interval 10 ft
0 100 200 300 400
Map Scale (ftUS)
0 2 4 6 8 10 12 14 16 18 20
Apparent Conductivity (mS/m)
Area of interference from surface or subsurface infrastructure
Anomalous low apparent conductivity
- may be caused by fractured rock, vugs, and possible near-surface voiding.
Increased potential for karst
Subsurface Utillities As of 11/2020 (APWA Color Codes)
- White highlighted lines are proposed new
Figure B-22
Signal may be associated
National Park Service
FDEM Results: Area 3, Coil 2 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
506200 506300 506400 506500 506600 506700 506800 506900 507000 507100 507200 507300 Easting (ftUS)
506200 506300 506400 506500 506600 506700 506800 506900 507000 507100 507200 507300
FDEM Coil 2 Conductivity (2.82 m coil separation)
N or th in g
(ft U
S)
CRS: New Mexico East (ftUS)
Contour Data: USGS 3DEP, index contour interval 10 ft
0 100 200 300 400
Map Scale (ftUS)
0 2 4 6 8 10 12 14 16 18 20
Apparent Conductivity (mS/m)
Area of interference from surface or subsurface infrastructure
Anomalous low apparent conductivity
- may be caused by fractured rock, vugs, and possible near-surface voiding.
Increased potential for karst
Subsurface Utillities As of 11/2020 (APWA Color Codes)
- White highlighted lines are proposed new
Figure B-23
National Park Service
FDEM Results: Area 3, Coil 3 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
506200 506300 506400 506500 506600 506700 506800 506900 507000 507100 507200 507300 Easting (ftUS)
506200 506300 506400 506500 506600 506700 506800 506900 507000 507100 507200 507300
FDEM Coil 3 Conductivity (4.49 m coil separation)
N or th in g
(ft U
S)
CRS: New Mexico East (ftUS)
Contour Data: USGS 3DEP, index contour interval 10 ft
0 100 200 300 400
Map Scale (ftUS)
0 2 4 6 8 10 12 14 16 18 20
Apparent Conductivity (mS/m)
Area of interference from surface or subsurface infrastructure
Anomalous low apparent conductivity
- may be caused by fractured rock, vugs, and possible near-surface voiding.
Increased potential for karst
Subsurface Utillities As of 11/2020 (APWA Color Codes)
- White highlighted lines are proposed new
Figure B-24
November 2022Checked by: D. LaymonDrafted by: D. Trekas
National Park Service
ERT Anomalies Area 3 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
506200 506275 506350 506425 506500 506575 506650 506725 506800 506875 506950 Easting (ftUS)
506200 506275 506350 506425 506500 506575 506650 506725 506800 506875 506950
N or th in g
(ft U
S)
CRS: New Mexico East (ftUS)
Contour Data: USGS 3DEP, index contour interval 10 ft
0 50 100 150 200
Map Scale (ftUS)
Figure B-25
ERT Line < = 20 ft.
>20 - >50 ft.
Interpreted Major ERT Anomaly >30,000 ohm-m
< = 20 ft.
>20 - >50 ft.
Interpreted High ERT Anomaly >10,000 ohm-m
< = 20 ft.
>20 - >50 ft.
Interpreted Low ERT Anomaly <50 ohm-m Subsurface Utillities
As of 11/2020 (APWA Color Codes)
- White highlighted lines are proposed new
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 Line Distance (ft)
Area 3 Line 1
El ev at io n (ft
10010
1000 10
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 Line Distance (ft)
Area 3 Line 2
El ev at io n (ft
Notes:
- Anomalous highly resistive zones (>30,000 ohm-m) may represent areas of either extremely competent limestone or potential air-filled karst features such as vugs, fractures, and voids. - High potential for karst
- High resistivity zones (>10,000 ohm-m) may represent competent limestone or air-filled karst features such as vugs, fractures, or voids. - Medium potential for karst
- Low resistivity zones (<50 ohm-m) may represent areas of highly weathered limestone, shale, or potential karst-related clay-filled solution zones.
- Some areas have extremely high contact resistance due to local soil and bedrock conditions. This may introduce noise to the data affecting models and interpretations.
10 30 50 70 90 200 10000 30000 50000
Apparent Resistivity (Ohm-m)
W E
W E
November 2022Checked by: R. BowlingDrafted by: D. Trekas
Project #: 22-182
National Park Service
ERT Lines Area 3 CAVE Geophysical Survey Carlsbad Caverns National Park, NM
Figure B-26
506200 506350 506500 506650 506800 Easting (ftUS)
N or th in g
(ft U
S)
Geophysical Investigative Report: Cave Geophysical Survey Services, Carlsbad Caverns National Park, Carlsbad, NM
APPENDIX B, AREA 4
| Geophysical Investigative Report_140P1322P0045P_Carlsbad_NM_FINAL_DRAFT_revision_A |
| Executive Summary |
| Table of Contents |
| List of Figures |
| List of Tables |
| 1.0 Introduction |
| 1.1 Project Overview |
| 1.2 Geologic Background |
| 1.3 Field Conditions |
| 2.0 Methods |
| 2.1 Ground Penetrating Radar (GPR) |
| 2.1.1 GPR Method |
| 2.1.2 GPR Survey Design |
| 2.1.3 GPR Data Processing and Interpretation |
| 2.2 Frequency Domain Electromagnetics (FDEM) |
| 2.2.1 FDEM Method |
| 2.2.2 FDEM Survey Design |
| 2.2.3 FDEM Data Processing and Interpretation |
| 2.3 Electrical Resistivity Tomography (ERT) |
| 2.3.1 ERT Method |
| 2.3.3 ERT Data Processing and Interpretation |
2.4 Combined Risk Mapping
| 3.0 Results |
| 3.1 Area 1 Results |
| 3.1.2 GPR |
| 3.1.3 FDEM |
| 3.1.4 ERT |
| 3.2 Area 2 Results |
| 3.2.1 GPR |
| 3.2.2 FDEM |
| 3.2.3 ERT |
| 3.3 Area 3 Results |
| 3.3.1 GPR |
| 3.3.2 FDEM |
| 3.3.3 ERT |
| 3.4 Area 4 Results |
| 3.4.1 GPR |
| 3.4.2 FDEM |
| 3.4.3 ERT |
| 3.5 Area 5 Results |
| 3.5.1 FDEM |
| 3.5.2 ERT |
| 3.6 Area 6 Results |
| 3.6.1 FDEM |
| 3.6.2 ERT |
| 4.0 Conclusions |
| 5.0 Limitations Declaration |
| 6.0 References Cited |
| 7.0 Digital Deliverables |
| Appendix A: Combined Risk Zone Maps |
| Appendix_A |
| A-1_Geophysical_Survey_Areas |
| A-2_Area_1_Combined_Risk_Map |
| A-3_Area_2_Combined_Risk_Map |
| A-4_Area_3_Combined_Risk_Map |
| A-5_Area_4_Combined_Risk_Map |
| A-6_Area_5_North_Combined_Risk_Map |
| A-7_Area_5_South_Combined_Risk_Map |
| A-8_Area_6_Combined_Risk_Map |
| Geophysical Investigative Report_140P1322P0045P_Carlsbad_NM_FINAL_DRAFT_revision_B |
| Appendix B: Detailed Geophysical Results |
| Appendix_B |
| Area_1_Cover |
| B-1_Area_1_GPR_Anomalies |
| B-2_Area_1_GPR_Example_Scanlines |
| B-3_Area_1_FDEM_Coil_1 |
| B-4_Area_1_FDEM_Coil_2 |
| B-5_Area_1_FDEM_Coil_3 |
| B-6_Area_1_ERT_Anomalies |
| B-7_Area_1_ERT_Lines_1_2_12_15 |
| B-8_Area_1_ERT_Lines_3-5 |
| B-9_Area_1_ERT_Lines_6-11 |
| Area_2_Cover |
| B-10_Area_2_GPR_Anomalies |
| B-11_Area_2_GPR_Example_Scanlines |
| B-12_Area_2_FDEM_Coil_1 |
| B-13_Area_2_FDEM_Coil_2 |
| B-14_Area_2_FDEM_Coil_3 |
| B-15_Area_2_ERT_Anomalies |
| B-16_Area_2_ERT_Lines_1-5 |
| B-17_Area_2_ERT_Lines_6-8 |
| B-18_Area_2_ERT_Lines_9_13-14 |
| B-19_Area_2_ERT_Lines_10-12 |
| Area_3_Cover |
| B-20_Area_3_GPR_Anomalies |
| B-21_Area_3_GPR_Example_Scanlines |
| B-22_Area_3_FDEM_Coil_1 |
| B-23_Area_3_FDEM_Coil_2 |
| B-24_Area_3_FDEM_Coil_3 |
| B-25_Area_3_ERT_Anomalies |
| B-26_Area_3_ERT_Lines_1-2 |
| Area_4_Cover |
| B-27_Area_4_GPR_Anomalies |
| B-28_Area_4_GPR_Example_Scanlines |
| B-29_Area_4_FDEM_Coil_1 |
| B-30_Area_4_FDEM_Coil_2 |
| B-31_Area_4_FDEM_Coil_3 |
| B-32_Area_4_ERT_Anomalies |
| B-33_Area_4_ERT_Lines_1-3 |
| Area_5_Cover |
| B-34_Area_5N_FDEM_Coil_1 |
| B-35_Area_5N_FDEM_Coil_2 |
| B-36_Area_5N_FDEM_Coil_3 |
| B-37_Area_5S_FDEM_Coil_1 |
| B-38_Area_5S_FDEM_Coil_2 |
| B-39_Area_5S_FDEM_Coil_3 |
| B-40_Area_5N_ERT_Anomalies |
| B-41_Area_5S_ERT_Anomalies |
| B-42_Area_5_Lines_1-3 |
| B-43_Area_5_Lines_4-5 |
| B-44_Area_5_Lines_6-8 |
| Area_6_Cover |
| B-45_Area_6_FDEM_Coil_1 |
| B-46_Area_6_FDEM_Coil_2 |
| B-47_Area_6_FDEM_Coil_3 |
| B-48_Area_6_ERT_Anomalies |
| B-49_Area_6_Lines_1-6 |
File details come from the government source that posted it. Updated .