WASHINGTON AND OREGON
(120th MERIDIAN OR PACIFIC STANDARD TIME)
January 3: 17:47*. Epicenter 46 degrees 00' north,
122 degrees 10' west, about 10 miles southeast of Cougar,
Wash. (Skamania County), S. Amboy (Che-
latchie Ranger Station). IV. Slow, 1-second
shock felt by several and frightened few in home.
Walls creaked. Also felt at Cougar (Swift Dam
Powerhouse, about 5 1/2 miles east of Cougar).
January 3: 23:26:01*. Epicenter 46 degrees 00'
north, 122 degrees 05' west, 15 miles south-southeast of
Mt. St. Helens, Wash. (Skamania County), S.
Felt over an area of approximately 2,000 square
miles of southwestern Washington, principally in
Clark and Skamania Counties. Maximum inten-
sity (damage) V.
INTENSITY (DAMAGE) V:
Amboy (about 20 miles southwest of epicenter).-
Felt by several and frightened few in community.
Furnishings shifted. Sharp motion, lasted 3
seconds; some said it felt and sounded like a car
hit the house.
North Bonneville.-Felt by and awakened all in
home. Hanging objects swung. Sudden, blast-
like 2-second shock; moderate earth noises from
northwest heard; "whooshing" sound after initial
shock.
INTENSITY (DAMAGE) IV: Carson, Cougar and
vicinity (slight tremors before and since), Steven-
son, Woodland (4 miles east of), and Yacolt.
Also felt at Battle Ground (no details).
INTENSITY (DAMAGE) IV IN OREGON: Portland
(West Hills area).
January 5: Between 18:00 and 19:00. Epi-
center 46 degrees north, 122 degrees 10' west, about 10
miles southeast of Cougar, Wash., S. Felt at the
Swift Dam Powerhouse (about 5 1/2 miles east of
Cougar) and at the Merwin Dam (about 10 miles
southwest of Swift Dam).
February 1: 21:50:13*. Epicenter a few
miles west of Longmire in Mt. Rainier National
Park, Wash., S. Longmire. V. Felt by all.
Set off snow avalanches in the mountains. Win-
dows and doors rattled. Rapid, 4-6 second
shock in north direction.
February 5: Between 14:00 and 15:00. Epi-
center about 10 miles southeast of Cougar, Wash.,
S. Two light shocks felt by observer at Swift
Dam Powerhouse (about 5 1/2 miles east of Cougar).
February 9: 21:55. Light shock felt by two
at Swift Dam Powerhouse (about 5 1/2 miles east
of Cougar, Wash.).
February 21: 00:35. Light shock felt at
Swift Dam Powerhouse (about 5 1/2 miles east of
Cougar, Wash.).
May 21: 17:58:50*. Entiat, Wash. IV.
Felt by many in community; frightened few in
home. Windows rattled; hanging objects swung.
Rapid, 15-second shock. Slightly felt at Wenat-
chee by observer and wife sitting. Motion slow,
lasted few seconds. It was reported the shock
was due to impounding of water in newly created
Lake Entiat at Rocky Reach Dam and Hydro-
electric Plant (about 10 miles upstream from
Wenatchee on the Columbia River). Recorded
at Seattle, Longmire, and Tumwater Seismo-
graph Stations.
May 25: 21:51. Washington. IV. Felt
by several; awakened and frightened few at
Merwin, Swift, and Yale dams in the Cougar-
Ariel areas. Windows and dishes rattled; rapid
motion, duration 10 seconds. At Longmire,
felt by observer sitting. Windows rattled; rapid,
1-3 second shock in east-west direction; faint
earth noises from east heard. Felt in home and
community at Morton, where dishes rattled;
rapid, 2-second shock.
June 1: 20:05. Cougar, Wash. (Swift Dam,
about 5 1/2 miles east of Cougar). III. Slight
shock felt by three persons.
June 28: 02:22:44*. Wenatchee (Rocky
Reach Dam), Wash. IV. Felt by several and
awakened few. Doors rattled; rapid and slow
motion, duration 10 seconds. Recorded at
Seattle, Longmire, and Tumwater, Wash. This
disturbance was also believed due to impounding
of water in the newly created Lake Entiat at
Rocky Reach Dam.
July 28: 06:52:44*. Swift Dam, Wash. (about
5 1/2 miles east of Cougar). IV. Felt by several;
awakened few. Windows, doors, and dishes
rattled. Also felt at Yale Dam (about 8 miles
southwest of Cougar).
August 18: 20:56:24.1 (main shock) and 21:06.
Epicenter 44.7 degrees north, 122.5 degrees west,
northwestern Oregon, W. Magnitude 4.5. Felt over
an area of approximately 7,000 square miles of north-
western Oregon. Reported felt from Oakridge,
Oreg., in southwest Lane County, north to areas
along the Lewis River in Cowlitz County, Wash.,
a distance of about 160 miles. It was reported
not felt in the coastal areas. Maximum in-
tensity (damage) VI at Albany and Lebanon,
where minor damage occurred.
INTENSITY (DAMAGE) VI:
Albany.-Generally felt. Plaster wall cracks
reported by some residents.
Lebanon (about 10 miles southeast of Albany).-
Felt by all. Two traffic lights, suspended over
intersections, fell; five signs fell; two house
chimneys toppled; store windows broken.
INTENSITY (DAMAGE) V: Keizer (about 5 miles
north of Salem), Salem (two shocks felt), and
Sublimity (about 15 miles southeast of Salem).
INTENSITY (DAMAGE) IV: Blue River area
(about 25 miles northeast of Eugene), Detroit,
Eugene, Oakridge (about 30 miles southeast o
Eugene), Portland, and Silverton (about 13
miles northeast of Salem).
INTENSITY (DAMAGE) IV IN WASHINGTON: Ariel
Cougar areas at Merwin, Swift, and Yale Dams.
Also felt (no details) at Corvallis, Mill City,
Scio, and Sweet Home, Oregon.
September 9: (about). Roosevelt, Wash.
One person reported feeling a shock about
week previous to September 15.
September 15: 19:25:00*, 22:48, 22:50. Epi
center 45 degrees 58' north, 122 degrees 10' west,
southeast of Cougar, Wash., in Gifford Pinchot
National Park, S. Felt over an area of approximately
7,000 square miles of southwestern Washington
and northwestern Oregon. (See map, p. 30.)
Maximum intensity (damage) VI at Swift Dam
(about 5 1/2 miles east of Cougar). No damage
reported.
INTENSITY (DAMAGE) VI:
Swift Dam (about 5 1/2 miles east of Cougar).-
Felt by all and frightened many in community.
Small objects overturned; knickknacks fell.
Trees, bushes shaken strongly. Hanging objects
swung east-west. Rapid, 20-second shock in
east-west direction. Also hard jolt felt at 22:48;
hard jolts rattled objects JD house at 22:50.
INTENSITY (DAMAGE) v: Amboy, Brush Prairie,
Cougar (Lewis Ranger Station), Government
Mineral Springs (about 15 miles northwest of
Carson), Heisson, North Bonneville, and
Stevenson.
INTENSITY (DAMAGE) V IN OREGON: Corbett
(midway up Larch Mountain).
INTENSITY (DAMAGE) IV: Ajlune, Appleton
(6 miles south of), Ashford, Battle Ground,
Bingen, Cathlamet, Cook (5 miles west of),
Curtis, Eatonville, Glenoma, Klickitat, Kosmos,
La Center, Mayfield, Mineral, Morton, Mossy-
rock, Orchards, Packwood, Puyallup, Randle and
Randle Ranger Station, Ridgefield, Toledo (1
mile northeast of), Vancouver, and Yacolt.
INTENSITY (DAMAGE) IV IN OREGON: Bonne-
ville, Clatskanie, Fairview, Government Camp,
Oregon City, Portland, Rainier, Sandy, and
Scappoose-
INTENSITY (DAMAGE) I TO III: Ariel, Camas,
Carrolls (near, on Columbia River), Castle Rock,
Chehalis, Cinebar, Elbe, Husum, Longview,
Richland (Hanford Atomic Works), Salkum,
Seattle, Silver Creek, Skamania, Spanaway,
Toutle and Spirit Lake Ranger Station, White
Salmon, Washougal (also felt shock around
midnight), and White Swan.
INTENSITY (DAMAGE) I TO III IN OREGON:
Albany, Brightwood, Deer Island, Detroit,
Gresham, Newberg, Odell, Vernonia, and Zigzag.
September 16: 03:45, 04:28. Aftershocks of
September 15 at 19:25:00*. Washington. Am-
boy. V. Felt by and frightened many in
community. Windows, doors, and dishes rat-
tled; walls creaked. Hanging objects swung
north-south. Rapid, 6-second shock. Felt by
observer lying down at the Lewis River Ranger
Station (Cougar), where windows, doors, and
dishes rattled; rapid, 10-second shock. Sharp,
hard jolts, followed by light quivering, felt at
Swift Dam (about 5 1/2 miles east of Cougar);
light shock felt at 04:28. Slight, abrupt shock
awakened observer from light sleep at Battle
Ground. At Klickatat: "Noise heard in a.m."
September 17: 07:55:58* (principal after-
shock of September 15 at 19:25:00*), 08:12,
08:34. Epicenter 45 degrees 58' north, 122 degrees
10' west, southeast of Cougar, Wash., in Gifford
Pinchot
National Park, S. Felt over an area of approxi-
mately 9,000 square miles of southwestern Wash-
ington and northwestern Oregon. Maximum
intensity (damage) VI. Slight damage reported
at few towns along the Columbia River.
INTENSITY (DAMAGE) VI:
Cougar (Lewis River Ranger Station).-Felt by
all in community; awakened and frightened few.
Small objects shifted; vases, etc., overturned.
Hanging objects swung north. Rapid motion;
lasted 20 seconds; moderate earth noises heard.
North Bonneville.-Felt by all in community.
Old house shifted on foundation about 1 inch.
Small objects shifted. Automobile rocked
strongly. Rapid, 5-second shock in west-east
direction; moderate earth noises from west
heard by many 1 second before shock.
Stevenson.-Felt by all and frightened few in
community. Damage slight. Chimneys and
cement foundations cracked; basement floor
cracked. Wood stove moved 6 inches. Plate
glass windows "rippled like Rags." Small
objects and furnishings shifted. Rapid, 2-second
shock; moderate earth noises heard by many
about 1/2 second before shock.
INTENSITY (DAMAGE) VI IN OREGON:
Latourell Falls.-Felt by and frightened all in
community. Few cracks in heavy cement-
block basement foundation (dirt floor in base-
ment). Trees, bushes shaken strongly; entire
house shaken strongly; hanging objects swung
east-west. Rapid motion in east-west direction,
long duration; loud earth noises from east-west,
like thunder or approaching train, heard by
many before shock.
INTENSITY (DAMAGE) v: Amboy, Ariel (Mer-
win Dam), Carson and Hemlock Ranger Station
about 10 miles northwest of Carson, Cook,
Seattle, Swift Dam (about 5y2 miles east of
Cougar; also booming earth noises heard at
08:12; moderate tremor at 08:34), Washougal,
and Yale Dam (about 8 miles southwest of
Cougar) .
INTENSITY (DAMAGE) V IN OREGON: Bridal
Veil, Hillsboro, Manning (near), Parkdale, and
Portland.
INTENSITY (DAMAGE) IV: Kosmos, La Center,
Mayfield, Mossyrock, Packwood, Randle and
Randle Ranger Station, Skamania, Vancouver,
and White Salmon.
INTENSITY (DAMAGE) IV IN OREGON: Aurora,
Beaverton, Brightwood, Buxton, Clackamas,
Deer Island, Government Camp, Hood River,
Mulino, Newberg, Odell, Rhododendron, Scap-
poose, The Dalles, Troutdale, Zigzag, and
Yamhill.
INTENSITY (DAMAGE) I TO III: Appleton (2
miles north of), Castle Rock, Elbe, Frances,
Glenorna, Mineral, Raymond (3 miles west of),
and Troutlake (3 miles southwest of).
INTENSITY (DAMAGE) I TO III IN OREGON:
Bonneville, Columbia City, Corbett, Corvallis,
Fairview, Gaston, Monitor, Saint Helens, Sher-
wood, Timber (about 35 miles northwest of
Portland), and Woodburn.
October 30: 19:35. Epicenter 48 degrees 25' north,
120 degrees 00' west, 17 miles west of Okanogan, S.
Felt over an area of approximately 1,200 square
miles of Okanogan County, Wash. Maximum
intensity (damage) V at three places.
INTENSITY (DAMAGE) V:
Conconully.-Felt by all; frightened few.
Windows and dishes rattled. Rapid, brief,
explosivelike shock; moderate earth noises heard
by many.
Malott.-Felt by all in community; frightened
few. Rapid, 30-second shock, beginning with
blastlike motion followed by short period of
shaking; loud earth noises heard.
Methow.-Felt by all in community. Windows
doors, and dishes rattled. Felt like large object
hit side of house, "Motion like a terrific far-off
blast."
INTENSITY (DAMAGE) IV: Brewster, Okanogan,
Omak (north section), Riverside, Synarep, and
Winthrop (3 miles south of).
INTENSITY (DAMAGE) I TO III: Carlton.
November 6: 17:29:10*. Epicenter 45 degrees 40'
north, 122 degrees 52' west about, 15 miles northwest of
downtown Portland, Oreg., S. Felt over an
area of approximately 9,000 square miles of
northwest Oregon and southwest Washington.
Maximum intensity (damage) VI at Portland
and four other towns. Slight plaster cracking
was the principal damage reported. Some
persons thought this was the sharpest shock
felt in Portland since April 13, 1949.
INTENSITY (DAMAGE) VI:
Portland.-Generally felt; frightened many.
Damage slight. Plaster cracked; part of brick
chimney fell; interior lights broken; door frames
jammed; water fountain sprung leak. Stock
fell from shelves in grocery stores; small objects
and furnishings shifted. Trees, bushes shaken
strongly. Window "rippled like waves." Loud
earth noises from northwest, west-east, and north
heard; various directions of motion-south-
west, west-east, and east-west.
Glenwood (about 25 miles west by north of Port-
land.-Felt by all in community. Concrete-
block foundation of service station broken where
blocks join. Store building rocked. Loud rumb-
ling earth noises, like several noisy trucks passing,
from northeast heard by many.
Milwaukee (about 10 miles southeast of Portland
city center.-Felt by all in community. Heavy
porch roof on house undergoing repairs and
remodeling fell about 18:30. Small objects and
furnishings shifted. Rapid, 1-minute shock
faint earth noises heard.
Scappoose (about 20 miles north by west
Portland).-Felt by all; awakened and frightened
few in community. Damage slight (no details).
Trees, bushes shaken slightly. Rapid, 5-second
shock in northeast direction; faint earth noises
from northeast heard by many.
Vernonia (about 32 miles northwest of Port-
land).-Felt by all and frightened few in com
munity. Damage slight. Windows broken.
Small objects shifted; knickknacks fell. Trees,
bushes shaken moderately. Hanging objects
swung east-west. Rapid, 7-10 second shock
moderate rumbling earth noises heard by many
during shock.
INTENSITY (DAMAGE) V: Banks, Brightwood,
Columbia City, Deer Creek (Merrill Creek Road,
l 1/2 miles from Deer Creek), Dundee, Eagle Creek,
Estacada (7 miles east of), Gresham, North
Plains, Oregon City, Orenco, Rainier, Rhodo-
dendron, Tillamook, Timber, and West Linn.
INTENSITY (DAMAGE) V IN WASHINGTON: Camas,
La Center, Vancouver, and Woodland.
INTENSITY (DAMAGE,) IV: Aloha, Birkenfeld,
Bonneville, Buxton, Clackamas, Clifton, Clover-
dale, Corbett, Detroit, Forest Grove, Garibaldi,
Gaston, Gates, Goble, Government Camp,
Hillsboro, Jewell, Lake Oswego, Latourell Falls,
Manning, Marquam, Molalla, Mount Hood,
Mulino, Netarts, Odell, Pacific City, Saint
Helens, Sandy, Scotts Mills, Sherwood, Trout-
dale, Tualatin, Warren, Westport, and Yamhill.
INTENSITY (DAMAGE) IV IN WASHINGTON: Am-
boy, Battle Ground, Bingen, Brush Prairie,
Carrolls, Carson, Castle Rock, Cook, Cougar,
Heisson, Home Valley, Husum, Kalama, Kelso,
Longview, North Bonneville, Orchards, Ridge-
field, Ryderwood, Skamokawa, Stevenson,
Toutle, Underwood, Washougal, White Salmon,
and Yacolt.
INTENSITY (DAMAGE) I TO III: Beaver, Beaver-
creek, Boring, Brownsmead, Canby, Cannon
Beach, Donald, Fairview, Hood River, Nehalem,
Neskowin, Rockaway, Saint Helens, Tigard,
Wilsonville, and Woodburn.
INTENSITY (DAMAGE) I TO III IN WASHINGTON:
Ariel and Cathlamet.
November 7: 09:53 and 10:05. Spokane,
Wash. Press reported Spokane was jarred by
shocks of local source. Recorded at Mt. St.
Michael's east of Spokane.
November 7: 13:30. Oregon and Washing-
ton. Portland. V. Press reported the shock
was felt principally in Portland and surrounding
areas. Calls were received from all parts of the
city, but few persons in the downtown area felt
it. Pictures tilted on walls and china clinked in
various parts of the city. TV slid across floor.
Also felt at Vancouver and Washougal, Wash.
Other slighter tremors felt during the afternoon.
November 30: 00:13- Epicenter 47 degrees 38'
north, 122 degrees 28' west, in Puget Sound Channel of
Magnolia section of Seattle, S. Felt over a
small area. IV. At Bellevue, felt by all in
home (awake). Windows and doors rattled;
house creaked; rapid, 10-second shock; direction
seemed south-north. Felt by observer lying
down at Bothell, where frame creaked; rapid,
3-second shock in north direction. At Bremer-
ton, felt by and frightened all in home; walls
creaked; seemed to be one brief south-north
shake, with none of the usual trembling motion
after shake. At Kirkland, rapid, 2-second shock
felt by observer lying down; windows rattled;
moderate earth noises heard 1 second before
shock. At Mercer Island (northwest end), felt
by observer lying down; frame creaked; rapid
motion; faint earth noises heard. At Seattle,
press reported calls were received from the
Magnolia and Queen Anne Hills sections. House
creaked; doors rattled and swung; bed shaken
slightly. Motion rapid and slow, lasted from
2-3 seconds to 2 minutes; direction east-west.
Felt by all in home at Woodinville, where
windows rattled. Felt by several in home and
awakened few at Redmond. At Renton (near
racetrack west of Renton), engineers believed
the shock was responsible for a sudden drop of
about 1.0 inch in a 15 by 20 foot fill. Also felt
at Kingston.
December 16: (a.m.) Portland, Oreg. Press
reported a slight shock was felt in Portland
"early today."
UW Dept. of Earth and Space Sciences ..... . PNW EARTHQUAKES