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

Cayucos

Morro Bay

Point Estero

Estero Bay

121°10' 121°5' 121° 120°55' 120°50'

35°25'

35°20'

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

for references) in Estero Bay map area. Blue line is shoreline. See sheet 3 for source of 

onshore elevation data.

Cayucos

Morro Bay

Point Estero

Estero Bay

80

60

20

40

140

160

180

200

120

100

220

240

121°10' 121°5' 121° 120°55' 120°50'

35°25'

35°20'

260

220

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

Estero Bay map area (red outline in index map). White lines are magnetic-survey boundaries. 

Black and red lines are faults (see sheet 3 for symbol explanation). Brown lines are 

bathymetric contours (contour interval, 10 m). Blue line is shoreline. See sheet 3 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

80

60

20

40

160

140

180

200

120

100

220

240

121°10' 121°5' 121° 120°55' 120°50'

35°25'

35°20'

Cayucos

Morro Bay

Point Estero

Estero Bay

Figure 1. Shaded-relief multibeam bathymetry of Estero Bay map area. Brown lines are 

bathymetric contours (contour interval, 10 m). Blue line is shoreline. See sheet 3 for sources 

of bathymetry, bathymetric contours, and onshore elevation data.

260

200

120

140

160

180

60

40

80

100

20

121°10' 121°5' 121° 120°55' 120°50'

35°25'

35°20'

Cayucos

Morro Bay

Point Estero

Estero Bay

Figure 4. Smaller, simplified (map-unit labels have been removed) version of map on sheet 3 

(for reference only), showing offshore geology and geomorphology of Estero Bay map area. 

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

3 for explanation of map units and other map symbols, as well as for sources of shaded-relief 

bathymetry, contours, and onshore elevation data.

Shaded-Relief Bathymetry, Seismic-Reflection Tracklines, and Magnetic Anomalies in Estero Bay 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 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

CALIF.

MAP LOCATION

13°

APPROXIMATE MEAN

DECLINATION, 2015

MAGNETIC NORTH

TRUE NORTH

MILES

FEET

KILOMETERS

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Map 3327

Sheet 4 of 6

Pamphlet accompanies map