Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the 

U.S. Government

This map was printed on an electronic plotter directly from digital files. Dimensional calibration may vary between electronic plotters 

and between X and Y directions on the same plotter, and paper may change size due to atmospheric conditions; therefore, scale and 

proportions may not be true on plots of this map.

For sale by U.S. Geological Survey, Information Services, Box 25286, Federal Center, Denver, CO 80225, 1–888–ASK–USGS

Digital files available at http://dx.doi.org/10.3133/ofr20151191

Suggested Citation: Golden, N.E., Cochrane, G.R., and Krigsman, L.M., 2015, Ground-truth studies, Offshore of Scott Creek map area, 

California, sheet 6 in Cochrane, G.R., Dartnell, P., Johnson, S.Y., Greene, H.G., Erdey, M.D., Dieter, B.E., Golden, N.E., Endris, C.A., 

Hartwell, S.R., Kvitek, R.G., Davenport, C.W., Watt, J.T., Krigsman, L.M., Ritchie, A.C., Sliter, R.W., Finlayson, D.P., and Maier, K.L. (G.R. 

Cochrane and S.A. Cochran, eds.), California State Waters Map Series—Offshore of Scott Creek, California: U.S. Geological Survey 

Open-File Report 2015–1191, pamphlet 40 p., 10 sheets, scale 1:24,000, http://dx.doi.org/10.3133/ofr20151191.

ISSN 2331-1258 (online) 

http://dx.doi.org/10.3133/ofr20151191

Figure 6. USGS-designed camera sled being launched off research vessel in preparation for ground-truth studies. 

Components include four digital video camcorders, one 8-megapixel digital SLR camera, lasers for scale, and various strobe 

and video lights, as well as telemetry instrumentation that records depth, altitude, and compass heading.

#

^

^

^

^

!

!

!

!

DISCUSSION

Between 2006 and 2007, the seafloor in the Offshore of Scott Creek map area in central California was mapped by California State 

University, Monterey Bay (CSUMB), by Fugro Pelagos, and by the U.S. Geological Survey (USGS), using both multibeam echosounders 

and bathymetric sidescan-sonar systems (see sheets 1, 2, 3). These mapping missions combined to collect bathymetry and acousticbackscatter data from about the 10-m isobath to out beyond the 3-nautical-mile limit of California’s State Waters. In order to characterize the 

bathymetry and acoustic-backscatter data into geologically and biologically useful information, the USGS ground-truth-surveyed the data by 

towing a camera sled (fig. 6) over specific locations throughout the map area in 2007 and 2012.

During the ground-truth-survey cruises, the camera sled was towed 1 to 2 m above the seafloor, at speeds of between 1 and 2 nautical 

miles/hour. The sled housed two standard-definition (640×480 pixel resolution) video cameras (one forward looking, the other downward 

looking), a high-definition (1,080×1,920 pixel resolution) video camera, and an 8-megapixel digital still camera, which captured a digital 

still photograph once every 30 seconds. The video was relayed in real time to the research vessel, where USGS and National Oceanic and 

Atmospheric Administration (NOAA) scientists recorded both the geologic and biologic character of the seafloor once every minute, using 

programmable keypads. The locations and directions of the camera-sled tracklines were chosen in order to visually inspect areas thought to 

represent the full range of bottom hardness and rugosity in the map area.

In the context of marine-fisheries management, benthic-habitat complexity can be divided into abiotic (geologic) and biotic (biologic) 

components. Benthic-habitat complexity refers to the visual classification of local abiotic and biotic vertical relief and structure that may 

provide potential refuge for both juvenile and adult forms of various species. Only abiotic attributes (primary- and secondary-substrate 

composition) were used in the production of the seafloor-character map on sheet 5. Classifications of primary and secondary substrate are 

based on the Wentworth (1922) scale of sediment grain-size categories, and the sand, cobble, and boulder sizes are classified as in Wentworth (1922). However, the difficulty in distinguishing the finest divisions in the Wentworth (1922) scale during video observations made it 

necessary to aggregate some grain-size classes: the granule and pebble sizes have been grouped together into a class called “gravel,” and the 

clay and silt sizes have been grouped into a class called “mud.” In addition, hard bottom and clasts larger than boulder size are classified as 

“rock.” Primary and secondary substrate, by definition, constitute greater than 50 and 20 percent of the seafloor during an observation, 

respectively.

This sheet contains a smaller, simplified (depth-zone symbology has been removed) version of the seafloor-character map (sheet 5), on 

which the camera-sled tracklines used to ground-truth-survey the sonar data are indicated by aligned colored dots, each dot representing the 

location of a recorded observation. Primary- and secondary-substrate compositions are shown by differently colored dots. The map also 

shows the locations of the detailed views of seafloor character along some of the tracklines (Boxes A through E) that are highlighted on this 

sheet (figs. 1A, 2A, 3A, 4A, 5A). Also shown are locations of samples (triangles) from usSEABED (Reid and others, 2006) that were used to 

supplement the ground-truth surveys. The seafloor-character map shows that this area is predominantly high-relief, rocky and bouldery 

habitat in the nearshore, out to depths of as much as 45 m, and low-relief sand and mud habitat in deeper waters.

Each detailed view (figs. 1A, 2A, 3A, 4A, 5A) shows the locations of camera-sled tracklines (aligned colored dots), as well as of the 

photographs (colored stars) taken along the tracklines. These photographs, which are representative of the seafloor, are displayed with a 

description of the observed seafloor characteristics recorded by USGS and NOAA scientists (figs. 1B through 1E; 2B through 2G; 3B 

through 3L; 4B through 4D; 5B through 5D). Only primary and secondary substrates are reported, although individual photographs may 

show more substrate types. Organisms, when present, are labeled on the photographs.

Ground-truth surveys in the Offshore of Scott Creek map area include approximately 8 trackline kilometers of video and 3,700 still 

photographs, in addition to 548 seafloor observations of abiotic and biotic attributes. A visual estimate of slope also was recorded.

GLOSSARY

Rugosity—A GIS-derived characterization of seafloor roughness, calculated as the ratio of the three-dimensional surface area of 

seafloor to the two-dimensional planar-base area, for each cell in the bathymetry grid.

Backscatter intensity—The amplitude of the reflected sonar signal (see sheet 3) used to infer the hardness of the bottom, determined 

after sonar-data processing has removed (as much as possible) the effects of water depth, angle of reflection, and bottom roughness.

Biocomplexity—The assessment of the presence or absence of biological structures that have the potential of providing shelter for 

fauna, determined by estimating the scale, the amount, and the morphology of biological relief (as described by Tissot and others, 2006).

Biocover—The visual estimate of the proportion of biologic cover by encrusting organisms: high, greater than 50 percent; moderate, 

between 50 percent and 10 percent; low, less than 10 percent.

REFERENCES CITED 

Reid, J.A., Reid, J.M., Jenkins, C.J., Zimmerman, M., Williams, S.J., and Field, M.E., 2006, usSEABED—Pacific Coast (California, 

Oregon, Washington) offshore surficial-sediment data release: U.S. Geological Survey Data Series 182, available at 

http://pubs.usgs.gov/ds/2006/182/.

Tissot, B.N., Yoklavich, M.M., Love, M.S., York, K., and Amend, M., 2006, Benthic invertebrates that form habitat on deep banks off 

southern California, with special reference to deep sea coral: Fishery Bulletin, v. 104, p. 167–181.

Wentworth, C.K., 1922, A scale of grade and class terms for clastic sediments: Journal of Geology, v. 30, p. 377–392.

EXPLANATION

Substrate class

Fine- to medium-grained smooth sediment—Low backscatter, low rugosity; typically mud to medium-grained sand; often 

rippled and (or) burrowed

Mixed smooth sediment and rock—Moderate to very high backscatter, low rugosity; typically coarse-grained sand, gravel, 

cobbles, and bedrock

Medium- to coarse-grained sediment—Very high backscatter, low rugosity; typically medium- to coarse-grained sediment, 

with varying amounts of shell hash; in scour depressions

Rock and boulder, rugose—High backscatter, high rugosity; typically boulders and rugose bedrock 

Location of real-time video observation and interpreted substrate class of seafloor

Fine- to medium-grained smooth sediment—Low backscatter, low rugosity; typically mud to medium-grained sand; often 

rippled and (or) burrowed

Mixed smooth sediment and rock—Moderate to very high backscatter, low rugosity; typically coarse-grained sand, gravel, 

cobbles, and bedrock

Medium- to coarse-grained sediment—Very high backscatter, low rugosity; typically medium- to coarse-grained sediment, 

with varying amounts of shell hash; in scour depressions

Rock and boulder, rugose—High backscatter, high rugosity; typically boulders and rugose bedrock 

Location of digital still photograph and interpreted substrate class of seafloor

Fine- to medium-grained smooth sediment—Low backscatter, low rugosity; typically mud to medium-grained sand; often 

rippled and (or) burrowed

Mixed smooth sediment and rock—Moderate to very high backscatter, low rugosity; typically coarse-grained sand, gravel, 

cobbles, and bedrock

Medium- to coarse-grained sediment—Very high backscatter, low rugosity; typically medium- to coarse-grained sediment, 

with varying amounts of shell hash; in scour depressions

Rock and boulder, rugose—High backscatter, high rugosity; typically boulders and rugose bedrock 

Interpreted substrate class depicted in digital still photograph—Indicated by colored frame around photograph (not shown on 

map; shown in figures only)

Fine- to medium-grained smooth sediment—Low backscatter, low rugosity; typically mud to medium-grained sand; often 

rippled and (or) burrowed

Mixed smooth sediment and rock—Moderate to very high backscatter, low rugosity; typically coarse-grained sand, gravel, 

cobbles, and bedrock

Medium- to coarse-grained sediment—Very high backscatter, low rugosity; typically medium- to coarse-grained sediment, 

with varying amounts of shell hash; in scour depressions

Rock and boulder, rugose—High backscatter, high rugosity; typically boulders and rugose bedrock 

Sample localities 

 From usSEABED (Reid and others, 2006)

Area of “no data”—Areas near shoreline not mapped owing to insufficient high-resolution seafloor mapping data; areas beyond 

3-nautical-mile limit of California’s State Waters were not mapped as part of California Seafloor Mapping Program 

3-nautical-mile limit of California’s State Waters

37°

36°40'

122°20' 122°

SANTA CRUZ

MONTEREY

MOSS 

LANDING

PIGEON

POINT

Limit of California’s

State Waters

Area of

Map

CALIF.

MAP LOCATION

0 5 10 Kilometers

0 5 10Nautical Miles

121°40'

Monterey

Bay

1

U.S. Geological Survey;

2

National Oceanic and Atmospheric Administration, National Marine Fisheries Service

Ground-Truth Studies, Offshore of Scott Creek Map Area, California

By

Nadine E. Golden,1 Guy R. Cochrane,1 and Lisa M. Krigsman2

2015

15 cm

3 Cam116_Tape58 Image 2016 -44m

Figure 5D. Digital still photograph no. E3 (see fig. 5A for location). 

Unconsolidated fine sand (water depth, 44 m). Abiotic complexity is low, biotic 

complexity is present, and biocover is high. Biocover includes brittle stars (bs). 

Distance between lasers (green dots) is 15 cm.

bs

15 cm

Figure 5C. Digital still photograph no. E2 (see fig. 5A for location). 

Unconsolidated, fine sand and shell hash (water depth, 44 m). Abiotic 

complexity is low, biotic complexity is present, and biocover is high. Biocover 

includes brittle stars (bs). Distance between lasers (green dots) is 15 cm.

2 Cam116_Tape58 Image 1977 -44m

bs

15 cm

Figure 5B. Digital still photograph no. E1 (see fig. 5A for location). Hardpan 

seabed that has unconsolidated, fine sand and shell hash (water depth, 44 m). 

Abiotic complexity is low, biotic complexity is absent, and biocover is absent. 

Distance between lasers (green dots) is 15 cm.

1 Cam116_Tape58 Image 1919 -44m

!( !(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!( !( !(

!(

!(

!(

!(

E3

E2

E1

Box E

Figure 5A. Detailed view of seafloor character mapped southwest of Davenport, 

approximately 2.3 km offshore (see Box E, on map, for location), showing locations of periodic 

real-time video observations (dots) and digital still photographs (stars; see figs. 5B through 5D) 

from camera line CAM116, cruise C–02–12–SC.

3 15 cm Cam115_Tape58 Image 1828 -38m

Figure 4D. Digital still photograph no. D3 (see fig. 4A for location). Mixed 

cobbles, gravel, sand, and shell hash (water depth, 38 m). Abiotic complexity is 

low, biotic complexity is absent, and biocover is low. Distance between lasers 

(green dots) is 15 cm.

2 Cam115_Tape58 Image 1815 -38m 15 cm

Figure 4C. Digital still photograph no. D2 (see fig. 4A for location). Rock outcrop 

(water depth, 38 m). Abiotic complexity is low, biotic complexity is present, and 

biocover is high. Biocover includes white plumed anemones, Metridium spp. 

(met); encrusting sponge (spo); and cup corals (cc). Distance between lasers 

(green dots) is 15 cm.

cc

met

spo

15 cm 1 Cam115_Tape58 Image 1805 -39m

Figure 4B. Digital still photograph no. D1 (see fig. 4A for location). Rock outcrop 

that has veneer of shell hash (water depth, 39 m). Abiotic complexity is 

moderate, biotic complexity is absent, and biocover is moderate. Biocover 

includes vermillion rockfish, Sebastes miniatus (rf); and encrusting sponge 

(spo). Distance between lasers (green dots) is 15 cm.

rf

spo

!(

!( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !(

!(

!(

!(

!(

!(

!(

!(

D2

D1 D3

Box D Figure 4A. Detailed view of seafloor character mapped west-southwest of Davenport, 

approximately 1.5 km offshore (see Box D, on map, for location), showing locations of 

periodic real-time video observations (dots) and digital still photographs (stars; see figs. 4B 

through 4D) from camera line CAM115, cruise C–02–12–SC.

11 Cam114_Tape57 Image 1560 -23m

15 cm

Figure 3L. Digital still photograph no. C11 (see fig. 3A for location). Rock outcrop 

and scattered shell hash (water depth, 23 m). Abiotic complexity is low, biotic 

complexity is absent, and biocover is low. Distance between lasers (green dots) 

is 15 cm.

Cam114_Tape57 Image 1503 -23m 10 15 cm

Figure 3K. Digital still photograph no. C10 (see fig. 3A for location). Rock outcrop 

(water depth, 23 m). Abiotic complexity is moderate, biotic complexity is absent, 

and biocover is high. Biocover includes sponges (spo); strawberry anemones, 

Corynactis californica (sta); and sea slug (ssl). Distance between lasers (green 

dots) is 15 cm.

ssl

sta

spo

Cam114_Tape57 Image 1500 -23m 15 cm 9

Figure 3J. Digital still photograph no. C9 (see fig. 3A for location). Rock outcrop 

(water depth, 23 m). Abiotic complexity is high, biotic complexity is absent, and 

biocover is low. Biocover includes sea star (sst); cup coral (cc); and spot 

prawn, Pandalus platyceros (pr). Distance between lasers (green dots) is 15 cm.

cc

sst

pr

Cam114_Tape57 Image 1455 -23m

15 cm

8

Figure 3I. Digital still photograph no. C8 (see fig. 3A for location). Rock outcrop 

(water depth, 23 m). Abiotic complexity is high, biotic complexity is absent, and 

biocover is moderate. Biocover includes encrusting sponge (spo); and 

strawberry anemones, Corynactis californica (sta). Distance between lasers 

(green dots) is 15 cm.

spo

sta

Cam114_Tape57 Image 1451 -23m 15 cm 7

Figure 3H. Digital still photograph no. C7 (see fig. 3A for location). Rock outcrop 

(water depth, 23 m). Abiotic complexity is high, biotic complexity is absent, and 

biocover is moderate. Biocover includes tubeworm holes (tw) and encrusting 

sponge (spo). Distance between lasers (green dots) is 15 cm.

spo

tw

Cam114_Tape57 Image 1417 -25m 15 cm 6

Figure 3G. Digital still photograph no. C6 (see fig. 3A for location). Rock outcrop 

(water depth, 25 m). Abiotic complexity is high, biotic complexity is absent, and 

biocover is moderate. Biocover includes blackeye goby, Rhinogobiops nicholsii 

(beg); snail (sn); sponge (spo); drift weed (dw); and cup coral (cc). Distance 

between lasers (green dots) is 15 cm.

spo

cc

beg

dw

sn

Cam114_Tape57 Image 1389 -25m

15 cm

5

Figure 3F. Digital still photograph no. C5 (see fig. 3A for location). Rock outcrop 

(water depth, 25 m). Abiotic complexity is moderate, biotic complexity is absent, 

and biocover is low. Biocover includes encrusting sponge (spo) and drift weed 

(dw). Distance between lasers (green dots) is 15 cm. 

spo

dw

Cam114_Tape57 Image 1355 -24m 15 cm 4

Figure 3E. Digital still photograph no. C4 (see fig. 3A for location). Interface 

between rock outcrop and sand channel (water depth, 24 m). Abiotic complexity 

is high, biotic complexity is absent, and biocover is high. Biocover includes sea 

star (sst); strawberry anemones, Corynactis californica (sta); snail (sn); and 

encrusting sponges (spo). Distance between lasers (green dots) is 15 cm.

spo

sn

sta

sst

Cam114_Tape57 Image 1344 -25m

15 cm

3

Figure 3D. Digital still photograph no. C3 (see fig. 3A for location). Rock outcrop 

(water depth, 25 m). Abiotic complexity is low, biotic complexity is absent, and 

biocover is high. Biocover includes encrusting sponge (spo); cup corals (cc); 

and strawberry anemones, Corynactis californica (sta). Distance between 

lasers (green dots) is 15 cm.

spo cc

sta

15 cm 2 Cam114_Tape57 Image 1325 -23m

Figure 3C. Digital still photograph no. C2 (see fig. 3A for location). Rock outcrop 

(water depth, 23 m). Abiotic complexity is moderate, biotic complexity is absent, 

and biocover is high. Biocover includes encrusting sponge (spo); strawberry 

anemones, Corynactis californica (sta); drift weed (dw); and snail (sn). Distance 

between lasers (green dots) is 15 cm.

sta

dw

spo

sn

1Cam114_Tape57 Image 1311 -24m 15 cm

Figure 3B. Digital still photograph no. C1 (see fig. 3A for location). Sand channel in 

rugose rock outcrop (water depth, 24 m). Abiotic complexity is moderate, biotic 

complexity is absent, and biocover is moderate. Biocover includes strawberry 

anemones, Corynactis californica (sta); and encrusting sponge (spo). Distance 

between lasers (green dots) is 15 cm.

sta

spo

!(

!(

!(

!(

!(

!(!(!( !(!( !(

!(!(

!(

!(

!(

!(!(!(!(!(!(

!(

!(

!(

!(!(

!(!(!(

Figure 3A. Detailed view of seafloor character mapped west of Scott Creek, 

approximately 0.7 km offshore (see Box C, on map, for location), showing 

locations of periodic real-time video observations (dots) and digital still 

photographs (stars; see figs. 3B through 3L) from camera line 114, cruise 

C–02–12–SC.

C11

C10

C9

C7 C8

C6C5

C4

C3 C2

C1

Box C

6 Cam113_Tape57 Image 0992 -60m

15 cm

Figure 2G. Digital still photograph no. B6 (see fig. 2A for location). Rock outcrop 

that has veneer of mud (water depth, 60 m). Abiotic complexity is moderate, 

biotic complexity is present, and biocover is moderate. Biocover includes 

gorgonians (g), cup corals (cc), and sea cucumber (sc). Distance between 

lasers (green dots) is 15 cm.

g

sc

cc

5 Cam113_Tape57 Image 0987 -61m

15 cm

Figure 2F. Digital still photograph no. B5 (see fig. 2A for location). Rock outcrop 

that has veneer of mud (water depth, 61m). Abiotic complexity is moderate, 

biotic complexity is present, and biocover is moderate. Biocover includes cup 

corals (cc) and sea cucumbers (sc). Distance between lasers (green dots) is 15 

cm.

sc

cc

4 Cam113_Tape57 Image 0960 -61m

15 cm

Figure 2E. Digital still photograph no. B4 (see fig. 2A for location). Rock outcrop 

that has veneer of mud (water depth, 61 m). Abiotic complexity is moderate, 

biotic complexity is present, and biocover is high. Biocover includes strawberry 

anemones, Corynactis californica (sta); cup corals (cc); sea cucumber (sc); sea 

fan, Swiftia spp. (sf); and gorgonians (g). Distance between lasers (green dots) 

is 15 cm.

sc sf

sta

cc

g

3

15 cm

Cam113_Tape57 Image 0950 -62m

Figure 2D. Digital still photograph no. B3 (see fig. 2A for location). Mixed 

boulders, cobbles, gravel, fine sand, and shell hash (water depth, 62 m). Abiotic 

complexity is moderate, biotic complexity is absent, and biocover is high. 

Biocover includes sea cucumbers (sc); cup corals (cc); sea fan, Swiftia spp. 

(sf); and drift weed (dw). Distance between lasers (green dots) is 15 cm.

cc

sc

sf

dw

sc

sc

15 cm

2 Cam113_Tape57 Image 0936 -61m

Figure 2C. Digital still photograph no. B2 (see fig. 2A for location). Rock outcrop 

that has veneer of fine sand and shell hash (water depth, 61 m). Abiotic 

complexity is low, biotic complexity is present, and biocover is high. Biocover 

includes solitary sea anemones (sa); sea cucumbers (sc); cup corals (cc); and 

sea fan, Swiftia spp. (sf). Distance between lasers (green dots) is 15 cm.

sf

sc

cc

sa

15 cm

1Cam113_Tape57 Image 0916 -63m

Figure 2B. Digital still photograph no. B1 (see fig. 2A for location). 

Unconsolidated, fine sand (water depth, 63 m). Abiotic complexity is low, biotic 

complexity is absent, and biocover is low. Biocover includes sea pen (sp). 

Distance between lasers (green dots) is 15 cm.

sp

Figure 2A. Detailed view of seafloor character mapped west of Scott Creek, 

approximately 5.5 km offshore (see Box B, on map, for location), near 3-nautical-mile 

limit of California’s State Waters (yellow line), showing locations of periodic real-time 

video observations (dots) and digital still photographs (stars; see figs. 2B through 2G) 

!( from camera line CAM113, cruise C–02–12–SC.

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!( !( !( !(

!( !( !( !( !( !( !( !( !( !( !( !( !(

!(

!(

!(

!(

!(

!(

!(

!(

!(

!(

B2

B1

Box B

B3 B4

B5

B6

15 cm

4 Cam112_Tape56 Image 0711 -23m

Figure 1E. Digital still photograph no. A4 (see fig. 2A for location). Interface 

between rock outcrop and fine sand and shell hash (water depth, 23 m). Abiotic 

complexity is moderate, biotic complexity is absent, and biocover is moderate. 

Biocover includes drift weed (dw) and encrusting sponge (spo). Distance 

between lasers (green dots) is 15 cm. 

dw

spo

15 cm

Cam112_Tape56 Image 0660 -23m

Figure 1D. Digital still photograph no. A3 (see fig. 1A for location). Mixed 

boulders, cobbles, gravel, sand, and shell hash (water depth, 23 m). Abiotic 

complexity is moderate, biotic complexity is absent, and biocover is moderate. 

Biocover includes sea star (sst), snail (sn), and encrusting sponge (spo). 

Distance between lasers (green dots) is 15 cm.

3

spo

sn

15 cm

2 Cam112_Tape56 Image 0654 -23m

Figure 1C. Digital still photograph no. A2 (see fig. 1A for location). Rock outcrop 

and shell hash (water depth, 23 m). Abiotic complexity is moderate, biotic 

complexity is present, and biocover is moderate. Biocover includes drift weed 

(dw). Distance between lasers (green dots) is 15 cm.

dw

Figure 1B. Digital still photograph no. A1 (see fig. 1A for location). Mixed 

boulders, cobbles, gravel, sand, and shell hash (water depth, 24 m). Abiotic 

complexity is moderate, biotic complexity is present, and biocover is low. 

Distance between lasers (green dots) is 15 cm.

Cam112_Tape56 Image 0559 -24m

15 cm

1

!( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !(

A4

A3

A2

A1

Figure 1A. Detailed view of seafloor character mapped west of Waddell Creek, approximately 

2.1 km offshore (see Box A, on map, for location), showing locations of periodic real-time video 

observations (dots) and digital still photographs (stars; see figs. 1B through 1E) from camera 

line CAM112, cruise C–02–12–SC.

Box A

sst

ONE MILE = 0.869 NAUTICAL MILES

1 0.5 0 1 KILOMETER

7000 3500 0 7000 FEET

2 1 0 2 MILES

SCALE 1:50 000

APPROXIMATE MEAN

DECLINATION, 2015

MAGNETIC NORTH

13 / ° 1 2

TRUE NORTH

Seafloor-character map simplified from map on sheet 5, this 

report. Video observations recorded and digital still 

photographs taken in 2007−2012. Sample localities from 

usSEABED (Reid and others, 2006)

GIS database and digital cartography by Nadine E. Golden

Manuscript approved for publication September 30, 2015

Onshore elevation data from California Coastal Conservancy (available 

from National Oceanic and Atmospheric Administration [NOAA] Coastal 

Service Center’s Digital Coast at http://www.csc.noaa.gov/digitalcoast/

data/coastallidar/) and from U.S. Geological Survey’s National Elevation 

Dataset (available at http://ned.usgs.gov/). Offshore shaded-relief 

bathymetry from map on sheet 2, this report. California's State Waters 

limit from NOAA Office of Coast Survey

Universal Transverse Mercator projection, Zone 10N

NOT INTENDED FOR NAVIGATIONAL USE

E

D

C B

A

122°20' 122°15'

37°05'

37°

Davenport

Scott Creek

Waddell Creek

37°05'

37°

122°20' 122°15'

Open-File Report 2015–1191

Sheet 6 of 10

Pamphlet accompanies map

U.S. Department of the Interior

U.S. Geological Survey