Map view. Colored shaded-relief bathymetry map of 

offshore of southern California. Colors show depth: reds 

indicate shallower areas; purples, deeper areas. Illumination 

azimuth is 300°, from 45° above horizon. Numbered arrows 

show viewing directions of perspective views shown on this 

sheet; numbers correspond to figure numbers of views.

Onshore imagery modified from LANDSAT-8 satellite data (available 

from U.S. Geological Survey, Earth Explorer, at 

http://earthexplorer.usgs.gov/). 

Offshore shaded-relief bathymetry from map on sheet 1, this report. 

Universal Transverse Mercator projection, Zone 11N

NOT INTENDED FOR NAVIGATIONAL USE

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/sim3324 or http://pubs.usgs.gov/sim/3324/

Suggested Citation: Dartnell, P., Driscoll, N.W., Brothers, D., Conrad, J.E., Kluesner, J., Kent, G., 

and Andrews, B., 2015, Colored shaded-relief bathymetry, acoustic backscatter, and selected 

perspective views of the inner continental borderland, Southern California: U.S. Geological 

Survey Scientific Investigations Map 3324, 3 sheets, http://dx.doi.org/10.3133/sim3324.

ISSN 2329-132X (online) and

http://dx.doi.org/10.3133/sim3324

Perspective views by Peter Dartnell, 2014. 

GIS database and cartography by Peter Dartnell.

Edited by Kate Jacques and Taryn Lindquist

Manuscript approved for publication April 6, 2015.

117°30'

117°30'

118°

118°

118°30'

118°30'

34°

34°

33°30'

33°30'

33°

33°

 Newport 

 Channel

Newport Beach

1

5

4

6

3

2

CALIF.

MAP LOCATION APPROXIMATE MEAN

DECLINATION, 2015

MAGNETIC NORTH

12 °

TRUE NORTH

U.S. Department of the Interior

U.S. Geological Survey

By

2015

Peter Dartnell, Neal W. Driscoll, Danny Brothers, James E. Conrad, Jared Kluesner, Graham Kent, and Brian Andrews

Colored Shaded Relief Bathymetry, Acoustic Backscatter, and Selected 

Perspective Views of the Inner Continental Borderland, Southern California

1 2 1 1 3 2 1

 U.S. Geological Survey;

 Scripps Institution of Oceanography;

 University of California, Santa Cruz

1

2

3

Perspective Views of Bathymetry

ONE MILE = 0.869 NAUTICAL MILES

5

10 10 KILOMETERS

0

5

10

0

10 MILES

Scientific Investigations Map 3324

 Sheet 3 of 3

Figure 1.—Regional perspective view to northeast across inner continental borderland, southern California. View highlights complex seafloor shaped by tectonic forces, sedimentary processes, and sea-level fluctuations. Bathymetric highs (for example, Santa Catalina Island, Thirtymile Bank, Lasuen Knoll, Crespi Knoll) and lows (for example, Catalina Basin, San Pedro Basin, San Diego Trough) are the result of tectonic deformation along an active margin. Large submarine canyon-andchannel systems as well as smaller gullies were cut into mainland shelf and slope, forming meandering paths around bathymetric highs and transporting sediment from mainland shelf to deep basins. Lower sea levels during glacial periods allowed rivers to connect with some offshore canyons, and wave action during lower sea levels smoothed mainland shelf (for example, San Pedro shelf). Vertical exaggeration of perspective view, 4x; distance across bottom of view, about 115 km; distance 

 from Santa Monica Mountains to San Diego, about 200 km.

Figure 3.—Perspective view to northwest between Santa Catalina Island and mainland Los Angeles area. Avalon Knoll is located 

at southeast end of San Pedro Basin. In this view, San Diego Trough Fault (see also, fig. 5) can be traced by vertical offset of 

seafloor (a) from San Gabriel canyon-and-channel system to northeast edge of Avalon Knoll; vertical offset at scarp (a), 7 m. 

Vertical exaggeration of perspective view, 4x; distance across bottom of view, about 15 km.

Figure 4.—Perspective view to northwest at mainland shelf and slope south of Dana Point. Slope is cut by variety of channels, 

gullies, and canyons. Oceanside canyon-and-channel system is to south (right), and lower reaches of Newport canyon-andchannel system is to north (left). Channels, gullies, and canyons serve as conduits that carry sediment off of shelf and into 

 offshore basins. These canyon-and-channel systems are largely inactive during sea-level highstands, but they become active

 during lowstands when shoreline is at shelf edge (Covault and others, 2007). Likely overbank deposits are visible near both

 canyon-and-channel systems: relatively large deposit (b) is visible where Newport channel meanders around bathymetric high

 southeast of Lasuen Knoll (to left, outside of figure view); smaller deposits (c) are visible near Oceanside canyon-and-channel

 system. Vertical exaggeration of perspective view, 4x; distance across bottom of view, about 18 km.

Figure 2.—Perspective view to north toward Los Angeles. Newport canyon-and-channel system and San Gabriel canyonand-channel system meander down mainland slope and around bathymetric highs of Lasuen and Crespi Knolls and Santa 

 Catalina Island. San Gabriel canyon-and-channel system, which can be traced for about 80 km, empties into bathymetric low

 southeast of Emery Knoll in Catalina Basin (see map view). Newport canyon-and-channel system can be traced for about 100

 km, from its head directly offshore of Newport Beach, then around Crespi Knoll and into San Diego Trough (see map view).

 Vertical exaggeration of perspective view, 4x; distance across bottom of view, about 22 km.

Figure 5.—Perspective view to northwest toward Santa Catalina Island. Solid white line shows location 

of bathymetric divide (d) between San Diego Trough and Catalina Basin (arrows show downslope 

direction). Dashed white lines show trace of San Diego Trough Fault Zone (SDTFZ; trace modified from 

Ryan and others, 2012), which can be followed next to and across series of seafloor ridges, including 

Crespi Knoll, “Offset Knoll” (Ryan and others, 2012), and Avalon Knoll. Source of sediment waves and 

overbank deposits (e), visible in San Diego Trough, is likely sediment passing through Newport 

canyon-and-channel system. Vertical exaggeration of perspective view, 4x; distance across bottom of 

view, about 9 km.

Figure 6.—Perspective view to southwest over San Diego Trough and Gulf of Santa Catalina. Dashed white lines show trace 

of San Diego Trough Fault Zone (SDTFZ; trace modified from Ryan and others, 2012), which can be followed from northwest 

(lower left) to southeast (right) by small offsets of seafloor, as well as of larger ridges. Main canyons and channels of 

Oceanside, Carlsbad, and La Jolla canyon-and-channel systems are clearly visible in this view. Oceanside 

canyon-and-channel system was active between 45 and 13 ka; Carlsbad canyon-and-channel system was active between 

about 50 and 10 ka; and La Jolla canyon-and-channel system was active during two time periods, between about 50 and 40 

ka and between 13 ka and present (Covault and others, 2007). All main deep-sea fan systems shown merge in San Diego 

Trough: yellow lines outline Carlsbad Canyon fan system (CCFS); red lines, La Jolla Canyon fan system (LJCFS); orange lines, 

Oceanside Canyon fan system (OCFS); brown lines, Newport Canyon fan system (NCFS). Vertical exaggeration of 

perspective view, 4x; distance across bottom of view, about 20 km.

Santa Catalina Island

Los Angeles

Thirtymile Bank

Lasuen Knoll

Crespi Knoll

Catalina Basin

San Diego Trough

San Diego

Avalon Knoll

San Pedro Basin

San Pedro Shelf

San Monica Mountains

Los Angeles

 San Gabriel canyon

and channel system

 Newport canyon

and channel system

Lasuen Knoll

Crespi Knoll

Santa Catalina 

 Island

Santa Catalina Island

Catalina Basin

San Diego Trough

d

Crespi Knoll

“Offset Knoll”

e

e

Avalon

 Knoll

Santa Catalina 

 Island

Los Angeles

Avalon Knoll

San Pedro Basin

a

SDTFZ

Dana Point

 San Gabriel canyon

and channel system

Gulf of Santa Catalina

 La Jolla Canyon

San Diego Trough

LJCFS

CCFS

NCFS

 La Jolla 

fan valley

 Newport canyon

and channel system

 Oceanside canyon

and channel system

b

c

c

References Cited

Covault, J.A., Normark, W.W., Romans, B.W., and Graham, S.A., 2007, Highstand fans in the California Borderland—The 

overlooked deep-water depositional systems: Geology, v. 35, no. 9, p. 783–786.

Ryan, H.F., Conrad, J.E., Paull, C.K., and McGann, M., 2012, Slip rate on the San Diego Trough Fault zone, inner California 

Borderland, and the 1986 Oceanside earthquake swarm revisited: Bulletin of the Seismological Society of America, v. 102, 

no. 6, p. 2300–2312.

Crespi Knoll

 Newport canyon

and channel system

SDTFZ

 Oceanside canyon

and channel system

 Carlsbad canyon

and channel system

OCFS

Prepared in cooperation with 

Scripps Institution of Oceangraphy

San Diego

Oceanside

Newport Beach

Los Angeles

Long Beach

San Gabriel 

 Canyon Newport 

 Canyon

La Jolla Fan Valley

Catalina Basin

San Pedro Basin

Santa Monica Basin

Lasuen Knoll

Crespi Knoll

Emery Knoll

Avalon Knoll

San Clemente Island

Santa Catalina 

 Island

Santa Monica

 Canyon

Redondo

 Canyon

Redondo Knoll

Oceanside

 Canyon

Carlsbad

 Canyon

La Jolla

Canyon

San Diego Trough