70°13' 70°10' 70°08' 70°06' 70°04' 70°02'

42°18'

42°19'

70°13' 70°11' 70°09' 70°07' 70°05' 70°03'

42°14'

42°16'

42°18'

42°19'

42°14'

42°16'

70°11' 70°09' 70°07' 70°05' 70°03'

70°12' 70°10' 70°08' 70°06' 70°04'

42°17'

42°15'

42°13' 42°13'

42°15'

42°17'

70°12'

70°02'

Prepared in cooperation with the

National Oceanic and Atmospheric Administration

U.S. Department of the Interior

U.S. Geological Survey

Colors represent the average change in elevation, in centimeters (cm), between a central area (13-meter [m] pixel) and the surrounding eight pixels (total area analyzed is 

three pixels by three pixels, or 39 × 39 m in size). For example, on the map, blue represents central pixels having an average elevation change of >70 to 80 cm with 

respect to their surrounding eight-pixel areas. Note the elevation-change increments in the color scale vary from 10 cm to 50 cm to 100 cm. A lter was applied to the 

ruggedness index image to smooth the boundaries between the mapped increments. The lter calculated the mean of the seabed terrain ruggedness index (TRI) value of 

each pixel and its eight neighboring pixels in a three-pixel by three-pixel grid that measures 39 × 39 m.

This index represents the range of seabed ruggedness observed in the Stellwagen Bank National Marine Sanctuary region. In quadrangle 6, seabed ruggedness ranges 

from 0–30 to >300–400 cm.

See Mapping Methods for explanation of topographic contour intervals. 

SEABED TERRAIN RUGGEDNESS INDEX

0–30 >30–40 >40–50 >50–60 >60–70 >70–80 >80–90 >90–100 >100–150 >150–200 >200–300 >300–400 >400–500 >500–600

Interval >30 to 100 cm

(10-cm increments)

Interval >1 to 2 m

(50-cm increments)

Interval >2 to 6 m

(100-cm increments)

Scientific Investigations Map 3341

Map B

STELLWAGEN BANK NATIONAL MARINE SANCTUARY

STELLWAGEN BANK

N I N E T Y M E T E R B A N K S

NORTH 

NINETY

BANK

SOUTH

NINETY

BANK

EAST

NINETY

BANK

MIDDLE

NINETY

BANK

Any use of trade, firm, or product names is for descriptive purposes only and does not imply 

endorsement by the U.S. Government

Digital files available at http://pubs.usgs.gov/sim/3341/

Suggested citation: Valentine, P.C., and Gallea, L.B., 2015, Seabed ruggedness, map B of Seabed 

maps showing topography, ruggedness, backscatter intensity, sediment mobility, and the 

distribution of geologic substrates in quadrangle 6 of the Stellwagen Bank National Marine 

Sanctuary region offshore of Boston, Massachusetts: U.S. Geological Survey Scientific 

Investigations Map 3341, scale 1:25,000, http://dx.doi.org/10.3133/sim3341.

ISSN 2329-132X (online)

http://dx.doi.org/10.3133/sim3341

Map B.—Seabed Ruggedness

Seabed Maps Showing Topography, Ruggedness, Backscatter Intensity, Sediment Mobility, and the

Distribution of Geologic Substrates in Quadrangle 6 of the Stellwagen Bank National Marine Sanctuary Region 

Offshore of Boston, Massachusetts

By

Page C. Valentine and Leslie B. Gallea

2015

Merrimack River

0 20 km

CAPE COD

CAPE

ANN

Plymouth

Provincetown

Gloucester

BOSTON

MAS SACHUSETTS

BAY

GULF

OF

MAINE

71°00'W 70°45'W 70°30'W 70°15'W 70°00'W

Location Map.—Shows quadrangle 6 (highlighted in yellow). Stellwagen Bank 

National Marine Sanctuary boundary is shown as a dashed line. Bathymetric 

contours are labeled in meters.

40

200

100

100

100

100

80

80

80

80

40

80

80

40

100

80 40

40

CAPE COD BAY

8

5

9

10 11 12

4

1 2 3

14 15

16 17 18

13

7

42°45'N

42°30'N

42°15'N

42°00'N

41°45'N

STELLWAGEN

6

BASIN

TILLIES BANK

STELLWAGEN

BANK

RACE POINT CHANNEL

JEFFREYS LEDGE

Mercator projection

Geodetic Reference System 1980; North American Datum of 1983

Longitude of central meridian 70°19' W; latitude of true scale 41°39' N

False easting 0 m; false northing 0 m

This map is not intended for navigational purposes.

SCALE 1:25 000 

ONE CENTIMETER ON THE MAP REPRESENTS 250 METERS ON THE SEA FLOOR 

1 .5 0 1 2 3 4 KILOMETERS

1 .5 0 1 2 NAUTICAL MILES 

CONTOUR INTERVAL 5 METERS

ADDITIONAL 1-METER CONTOURS INCLUDED TO SHOW BOTTOM ROUGHNESS

DATUM MEAN LOWER LOW WATER