WASHINGTON AND OREGON (105th MERIDIAN OR PACIFIC WAR TIME) January 3: 19:34:48.7.* Entiat, Wash. Felt by all. Rattled dishes and doors. January 27: 22:06:08.1* Near Stanwood, Wash. Felt by many. Some plaster fell. Intensity IV at Granite Falls and Snohomish. February 13: 20:02:9.1.* See Western Mountain Region. February 27: 04:00 (about). Entiat and Winthrop,, Wash. Felt slightly. March 2: 00:54:59.3* Near Entiat, Wash. Motion rapid, lasting 4 seconds. Awakened many in community. Also felt at Chelan and Waterville. April 29: 13:16:17.* Epicenter about 47.4 degrees north, 121.7 degrees west, BC. Ten miles southeast of North Bend, Wash. This earthquake was felt over the greater portion of Washington, a small section of western Idaho, and in the vicinity of Portland, Oreg. See map. Affected area covered approximately 50,000 square miles. Maximum intensity VII. The shock was the moist intense in this region since the quake of November 12, 1939. The 2-minute shaking was accompanied by a noise as of a muffled explosion. Although no damage was caused, the tre-
mors were powerful enough to dislodge bricks from a dozen or more homes in the Cle Elum area. Only one minor casualty resulted; a boy at Roslyn was struck on the head by a falling brick. Seismologists determined the shock originated in the Mount Si Fault, the old crack in the earth's crust that extends from North Bend almost due north along the west face of Mount Si to the town of Sultan. At the Mount Si Ranger Station, near North Bend, the earth buckled and heaved and tons of rock and earth cascaded down the 4,000 foot cliffs. Many local residents called the newspapers seeking information about the quake. INTENSITY VII: North Bend.-Felt by all in community. Trees and bushes shaken strongly. Cracked plaster and chimneys. Broke dishes, windows, and town water main. Damage was mostly to chimneys. Caused large rock slides on west face of Mount Si. Moderately loud to terrific muffled explosion-like sounds heard. Palmer.-Felt by all. Trees and bushes shaken strongly. Cracked plaster and ground. Overturned vases and small objects. Damage slight. Stampede Pass.-Buildings rocked back and forth. Slight damage as seams and joints spread in an east-west direction. Moderately loud, bumping and scraping subterranean sounds heard. INTENSITY VI: Baldi.-Felt by all. Rattled windows. Houses creaked. Spilled water from indoor containers in a northerly direction. Trees and bushes shaken moderately. Cedar Falls.-Motion bumping, with abrupt onset. Felt by all. Small rock slides across Cedar River. Muffled subterranean sounds heard. Cle Elum.-Felt by all in community. Frightened many. Cracked windows and chimneys. Hang- ing objects swung. Pendulum clocks stopped. Trees and bushes shaken moderately. Damage slight. Ellensburg.-Felt by many in community. Rattled dishes and cracked plaster. Elma.-Felt by several. Buildings creaked. Two north-south walls were cracked, cracks running south to north. Greenwater.-Felt by several. Bumping subterranean sounds heard by several before shock. Dam- age to a few old brick chimneys. Pictures displaced on east-west walls. Pendulum clocks stopped. Hyak.-Two shocks about 10 seconds apart. Felt by all in community. Slight visible swaying of buildings and trees. Articles fell from shelves. Index.-Felt by many. Small landslides occurred. Bumping subterranean sounds heard by many before shock. Visible swaying of buildings and trees. Cracked plaster in a few instances. Leavenworth.-Felt by all. Buildings creaked. Rumbling heard at time of shock. Visible swaying of buildings and trees. Slight damage to buildings. Some chimneys had top layers of bricks knocked to ground. Preston.-Rapid undulating motion, abrupt onset, accompanied by loud rumbling noise. Felt by all. Overturned small objects. Spilled water from indoor containers. Trees and bushes shaken moderately. Skykomish.-Felt by several. Buildings creaked. Moderately loud rumbling subterranean sound heard before shock. Pictures displaced. Wires on electric light poles swayed vigorously up and down. Snoqualmie.-Felt by many. Visible swaying of trees and light poles. Plastered ceilings cracked around edges; chimneys and crockery damaged. Display goods on shelves fell to floor. Roaring sub- terranean sounds heard by many before shock. INTENSITY V: Anacortes, Ardenvoir, Beverly, Coupeville, Chelan, Chewalah, Darrington, Entiat, Enumclaw, Ever- ett, Gifford, Coulee Dam, Lakebay, Lake Cle Elum, Landsburg, Mount Vernon, Olga, Orondo, Orting, Packwood, Quilcene, Sultan, Scenic, Tacoma, Waterville, Winthrop, and Yakima. INTENSITY IV: Ariel, Bothell, Bremerton, Bumping Lake, Camano Island, Centralis, Cheney, Clear Lake, Concrete, Connell, Deer Park, Des Moines, Easton, Eastsound, Elbe, Ephrata, Gig Harbor, Hartline, Hoodsport, Holden; Issaquah, Kahlotus, Kelso, Kirkland, Klickitat, La Conner, Lake Wenatchee, Langley, Lopez Island, Lucerne, Mazama, Mineral, Monotor, Monroe, Mount Vernon, Naches, Nespelem, Odessa, Oka- nogan, Olympia, Omak, Paradise, Point Roberts, Port Gamble, Port Townsend, Poulsbo, Prosser, Puyallup, Rockport, Rosalia, Sedro-Wooley, Shelton, South Bend, Spanaway, Spokane, Stevens Pass, Tieton Ranger Station, Twisp, Wenatchee, Wellpinit, and Wilkeson. INTENSITY IV IN OREGON: Fossil and Portland. INTENSITY I TO III: Arlington, Bellingham, Camas, Conconnlly, Coulee City, Davenport, Evans, Glacier, Granite Falls, Lind (six miles north of), Newport, Othello, Roche Harbor, South Bend, Springdale, Wilson Creek, and Yacolt. INTENSITY I TO III IN IDAHO: Potlatch. Negative reports were received from 59 places in Washington, and from 23 places in Oregon. Aftershock of preceding earthquake. Intensity VI at North Bend, Wash. Many were awakened, houses creaked, and vases overturned. Damage slight. Felt also at Enumclaw, Longmire, Orting. May 1: 12:46:04.* Aftershock of April 29 earthquake. Felt over considerable area in west-central Washington. Maximum intensity V. INTENSITY V: Cle Elum, Stampede Pass, and Waterville. INTENSITY IV: Bumping Lake, Coulee Dam, Lake Wenatchee, Leavenworth, Longmire, Palmer, Sultan, and Wilkeson. May 1: 21:01:43.* Aftershock of April 29 earthquake. Felt at North Bend, Wash. May 3: 21:00 (about). North Bend, Wash. Felt by three people. June 15: 15:25:02.* Epicenter probably in the Strait of Georgia near the international boundary. Intensity V at Point Roberts where trees and bushes were shaken strongly. Houses creaked and small objects were shifted. Intensity IV at Bellingham, Concrete, Friday Harbor, La Conner, Marietta, and Richardson. Negative reports were received from 27 places. September 22: 19:40. Walla Walla and College Place, Wash. Brief series of shocks with rapid onset. Felt strongly in Veterans Hospital section. Moderately, loud rumbling similar to muffled explosion pre- ceded shocks. Affected area extended as far as Blalock Lake. September 23: 02:57.8.* See Western Mountain Region. November 11: 21:05. Epicenter probably near San Juan Island, Wash. Felt, generally without dam- age at Chimacum, Coupeville, Double Bluff, and Port Townsend. Slight plaster cracks reported at Port Townsend. Negative reports were received from 10 places. November 23: 16:30. Packwood, Wash. Slight shock awakened many. Rattled windows, doors, and dishes. Hanging objects swung. Negative reports were received from 5 places.
UW Dept. of Earth and Space Sciences ..... . PNW EARTHQUAKES