San Luis

Obispo

Pismo 

Beach

Diablo Canyon

Power Plant

San Luis Bay

Point 

Buchon

Point 

San Luis

Shell Beach

Oceano

Figure 2. Trackline map of minisparker seismic-reflection surveys (green lines; see pamphlet 

for references) in Point San Luis map area. Blue line is shoreline. See sheet 5 for source of 

onshore elevation data.

120°55' 120°50' 120°45' 120°40'

35°15'

35°10'

35°5'

80

100

120

140

160

180

200

20

40

60

120°55' 120°50' 120°45' 120°40'

35°15'

35°10'

35°5'

San Luis

Obispo

Pismo 

Beach

Diablo Canyon

Power Plant

San Luis Bay

Point 

Buchon

Point 

San Luis

Shell Beach

Oceano

Figure 1. Shaded-relief multibeam bathymetry of Point San Luis map area. Brown lines are 

bathymetric contours (contour interval, 10 m). Blue line is shoreline. See sheet 5 for sources 

of bathymetry, bathymetric contours, and onshore elevation data.

120°55' 120°50' 120°45' 120°40'

35°15'

35°10'

35°5'

San Luis

Obispo

Pismo 

Beach

Diablo Canyon

Power Plant

San Luis Bay

Point 

Buchon

Point 

San Luis

Shell Beach

Oceano

Figure 4. Smaller, simplified (map-unit labels have been removed) version of map on sheet 5 

(for reference only), showing offshore geology and geomorphology of Point San Luis map 

area. Gray lines are bathymetric contours (contour interval, 10 m). Blue line is shoreline. See 

sheet 5 for explanation of map units and other map symbols, as well as for sources of 

shaded-relief bathymetry, bathymetric contours, and onshore elevation data..

Offshore geology and geomorphology mapped by Janet T. 

Watt and Samuel Y. Johnson, 2010-2013

GIS database and digital cartography by Janet T. Watt, 

Stephen R. Hartwell, and Theresa Fregoso

Edited by Taryn A. Lindquist

Manuscript approved for publication April 14, 2015

100

120

80

60

40

20

80

100

120

140

160

180

20

40

60

San Luis

Obispo

Pismo 

Beach

Diablo Canyon

Power Plant

San Luis Bay

Point 

Buchon

Point 

San Luis

Shell Beach

Oceano

80

100

120

20

40

60

120°55' 120°50' 120°45' 120°40'

35°15'

35°10'

35°5'

Figure 3. Map showing gridded (50 m) residual magnetic anomalies and mapped faults in 

Point San Luis map area (red outline in index map). White lines are magnetic-survey 

boundaries. Black and red lines are faults (see sheet 5 for symbol explanation). Brown lines 

are bathymetric contours (contour interval, 10 m). Blue line is shoreline. See sheet 5 for 

sources of bathymetric contours.

121°15' 121° 120°45'

35°30' 35°15'

0 2.5 5 10 Miles

nT

SAN SIMEON

POINT SAN LUIS

ESTERO BAY

 INDEX TO MAGNETIC SURVEYS

Langenheim, V.E., Jachens, R.C., and Moussaoui, K., 2009, Aeromagnetic survey 

map of the central California Coast Ranges: U.S. Geological Survey Open-File 

Report 2009–1044, available at http://pubs.usgs.gov/of/2009/1044/.

Langenheim, V.E., Watt, J.T., and Denton, K.M., 2012, Magnetic map of the Irish 

Hills and surrounding areas, San Luis Obispo County, central California: U.S. 

Geological Survey Open-File Report 2012–1080, scale 1:24,000, available at 

http://pubs.usgs.gov/of/2012/1080/.

Sliter, R.W., Triezenberg, P.J., Hart, P.E., Watt, J.T., Johnson, S.Y., and Scheirer, 

D.S., 2009, High-resolution seismic-reflection and marine magnetic data along 

the Hosgri Fault Zone, central California: U.S. Geological Survey Open-File 

Report 2009–1100, version 1.1, available at http://pubs.usgs.gov/of/2009/1100/.

EXPLANATION

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Map 3327

Sheet 6 of 6

Pamphlet accompanies map

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/sim3327 or http://pubs.usgs.gov/sim/3327/

Suggested Citation: Watt, J.T., Johnson, S.Y., Hartwell, S.R., and Roberts, M., 2015, Offshore geology and geomorphology from Point 

Piedras Blancas to Pismo Beach, San Luis Obispo County, California: U.S. Geological Survey Scientific Investigations Map 3327, 

pamphlet 6 p., 6 sheets, scale 1:35,000, http://dx.doi.org/10.3133/sim3327.

ISSN 2329-132X (online)

http://dx.doi.org/10.3133/sim3327

Shaded-Relief Bathymetry, Seismic-Reflection Tracklines, and Magnetic Anomalies in Point San Luis Map Area

Offshore Geology and Geomorphology from Point Piedras Blancas

to Pismo Beach, San Luis Obispo County, California

By

Janet T. Watt, Samuel Y. Johnson, Stephen R. Hartwell, and Michelle Roberts

2015

1 0.5 0 1 2 3 4

5000 2500 0 5000 10000 15 000

1 0.5 0 1 2 3 4

SCALE 1:66 000

CALIF.

MAP LOCATION

13°

APPROXIMATE MEAN

DECLINATION, 2015

MAGNETIC NORTH

TRUE NORTH

MILES

FEET

KILOMETERS