AREA OF IMAGE F

S

M398 - LINE 17 SPARKER

M398 - LINE 17 SIDESCAN

M197 - LINE 13 SIDESCAN

M197 - LINE 3 SIDESCAN

O1067 - LINE 20 SINGLE CHANNEL

C197 - LINE 46 BOOMER

M398 - LINE 19 SPARKER

M398 - LINE 36 SPARKER

C197 - LINE 47 BOOMER

C

D

F

E

G

H

I

J

K

vertical exaggeration x 29.4 at 1500 m/s

vertical exaggeration x 11.8 at 1500 m/s

vertical exaggeration x 13.3 at 1500 m/s

vertical exaggeration x 23.8 at 1500 m/s

vertical exaggeration x 11.1 at 1500 m/s

vertical exaggeration x 13.3 at 1500 m/s

vertical exaggeration x 17.5 at 1500 m/s

1 KILOMETER

1 KILOMETER

1 KILOMETER

1 KILOMETER

1 KILOMETER

1 KILOMETER

1 KILOMETER

0

75

150

TWO-WAY TRAVEL TIME,

1.0

IN SECONDS

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TWO-WAY TRAVEL TIME,

0.2

IN SECONDS

0.0

0.1

0.2

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TWO-WAY TRAVEL TIME,

IN SECONDS

0.0

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0.12

TWO-WAY TRAVEL TIME,

IN SECONDS

0.0

0.1

TWO-WAY TRAVEL TIME,

0.2

IN SECONDS

0.0

0.04

0.08

0.12

TWO-WAY TRAVEL TIME,

IN SECONDS

0.0

0.1

TWO-WAY TRAVEL TIME,

0.2

IN SECONDS

750

DEPTH, IN METERS

BELOW SEA LEVEL

0

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DEPTH, IN METERS

BELOW SEA LEVEL

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300

DEPTH, IN METERS

BELOW SEA LEVEL

90

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DEPTH, IN METERS

BELOW SEA LEVEL

0

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DEPTH, IN METERS

BELOW SEA LEVEL

DEPTH, IN METERS

BELOW SEA LEVEL

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DEPTH, IN METERS

BELOW SEA LEVEL

N

N S

W

W

E

E

SW NE

NW SE

N

S

3000 2000 1000 0

6000 7000 1000 2000 3000 4000 5000 1000 2000 3000 4000 5000 6000

SHOT NUMBER SHOT NUMBER SHOT NUMBER

10000 9000 8000 7000 6000 5000 4000 3000 2000 1000 0

SHOT NUMBER

SHOT NUMBER

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SHOT NUMBER SHOT NUMBER

3000 2000 1000 0 10000 9000 8000 7000 6000 5000 4000

SHOT NUMBER SHOT NUMBER

1530 1600 1630

TIME, IN HOURS

N

N

0 1000 2000 3000 4000 5000 6000 7000 8000 9000

run parallel to the coast between the Copalis 

River and the Quinault River. Anticlines and 

synclines can be matched between tracklines 

(red tie-lines), demonstrating the east-west 

orientation of the folds. Long dashed tie-lines 

indicate anticlines; short dashed lines indicate 

synclines. IMAGE D shows folded strata in the 

axis of an anticline exposed on the sea floor in a 

sidescan-sonar swath (375 m wide). These 

folds extend onshore. Faults associated with 

the onshore extensions of these anticlines offset 

Quaternary gravels. (See plate 1A for location 

of profiles and image.)

PROFILE E is from a trackline that runs perpendicular to the coast 

just offshore from Point Grenville. The anticlinal structure in the 

center of the image is diapiric. Fluids escaping from the strata into 

the water column are imaged as reflective "clouds" in the water 

column. Several tracklines in this area show fluids escaping from 

faults, from inclined strata that breach the sea floor, and from 

anticlinal structures.

PROFILE I depicts faulted upper 

Quaternary strata along a trackline that runs 

perpendicular to the coast just offshore 

from the Queets River.

PROFILE H depicts a faulted anticline on a 

trackline that runs perpendicular to the 

coast just offshore from Cape Shoalwater. 

Note thinning and pinchout of late 

Pleistocene strata against anticline between 

shotpoints 400 and 1000.

PROFILE J depicts a faulted anticline 

offshore from Grays Harbor. Note the 

strata that onlap the sides of the anticline. 

Note thinning and pinchout of late 

Pleistocene strata against anticline between 

shotpoints 5000 and 7000.

PROFILE K depicts two 

faulted anticlines offshore 

from Grayland. Note the 

folded strata that thin and 

pinch out against anticlines 

between shotpoints 1200 and 

2800 and between shotpoints 

8200 and 9600. 

IMAGE G shows a mosaic of sidescan sonar swaths 

(either 200 m or 375 m wide) that depict a sand-filled 

channel (lightest areas) crossing the bedrock surface 

west of Connor Creek. Dotted green line depicts 

inferred channel outlines.

IMAGE F shows sidescan-sonar swaths (375 m wide) 

from two crossing tracklines, one of which parallels the 

coast east of the Copalis River. Strata that are 

emergent on the sea floor appear as lighter areas (more 

reflective) and sea floor covered with fine-grained 

sediment appear as the darker areas (more absorbent). 

These images depict a faulted anticline that trends 

east-northeast just offshore from Connor Creek. The 

emergent strata curve around the axis of the fold, 

indicating its structural trend.

sea-floor offset

breached diapir

reflective "clouds"

"Grays Harbor" fault zone

"Grays Harbor" fault zone

pinchout of late Pleistocene strata

pinchout of late Pleistocene strata

pinchout of late Pleistocene strata pinchout of late Pleistocene strata

EXPLANATION

Trackline

Profile

0°

5°

10°

20°

V.E.

1:22.2

0°

5°

10°

20°

V.E.

1 : 11.1

0°

5°

10°

20°

V.E.

1:23.8

0°

5°

10°

20°

V.E.

1:13.3

0°

5°

10°

20°

V.E.

1:13.3

0°

5°

10°

20°

V.E.

1:11.8

0°

5°

10°

20°

V.E.

1:29.4

Fault

Unconformity

Stratigraphic reflector

First multiple

Fault

Unconformity

Stratigraphic reflector

First multiple

Fault

Unconformity

Stratigraphic reflector

First multiple

Fault

Unconformity

Stratigraphic reflector

First multiple

Fault

Unconformity

Stratigraphic reflector

First multiple

Fault

Unconformity

Stratigrahpic reflector

First multiple

Fault

Unconformity

Stratigraphic reflector

First multiple

A

B

C

C

D

F

G

E

I

H

K

J

LOCATION MAP

(see also plate 1A)

0 10 MILES

0 10 KILOMETERS

N

Area shown

in plate 1

SEISMIC REFLECTION PROFILES AND SIDESCAN SONAR IMAGES

FROM THE SOUTHERN WASHINGTON CONTINENTAL SHELF

By

Patricia A. McCrory, David S. Foster, William W. Danforth, and Michael R. Hamer

2002

McCrory, P.A., Foster, D.S., Danforth, W.W., and Hamer, M., 2002, Crustal Deformation 

at the Leading Edge of the Oregon Coast Range Block, Offshore Washington 

(Columbia River to Hoh River): US Geological Survey Professional Paper 1661–A