WASHINGTON AND OREGON 120th meridian or Pacific standard time March 22: 8:30. Alder, Wash. Weak. May 8: Early. Roseburg, Oreg. Meteor exploded, awakening many. June 20: 2:57.* Seattle, Wash. Weak. June 20: 3:50. Bothell, Wash. Weak shock. July 15: 20:30. White Salmon, Wash. Weak foreshock of the north Oregon earthquake at 23:08. July 15: 22:20. Mottinger, Wash. Slight foreshock of the north Oregon earth- quake at 23:08. July 15: 23:08.* "State Line earthquake" near Walla Walla, Wash., and Milton, Oreg. VII+. Epicenter within a few miles of 45 degrees 58' north, 118 degrees 18' west. Damage about $100,000. Area affected, about 105,000 square miles. See map on page 21, which is based on a mail canvass of the affected area
by the Bureau's Seismological Field Survey operating from San Francisco. According to B.J. Brown, "The buildings in the earthquake area are so irregularly distributed and their character and condition so varied that it has been impossible to fix with accuracy the destructive limits." Mr. Brown is author of an article entitled "The State Line Earthquake at Milton and Walla Walla" which appears in the July 1937 number (vol. 27, No. 3) of the Bulletin of the Seismological Society of America and covers many important aspects of the earthquake. The shock was strongest at Freewater, State Line, and Umapine, Oreg., where the intensities reached VII. The ground was badly cracked and there were marked changes in the flow of well water. In the cemeteries about 70 percent of the stones rotated clockwise, viewed from above. Some stones in close prox- imity to each other rotated in opposite directions. Mr. Brown's report also reveals interesting facts concerning the geology of the, epicentral region: "A spur of the Blue Mountains, known locally as the Touchet Ridge, extends from Milton west-northwest, crossing into Washington about 5 miles east of Wallula. The ridge crossed the Columbia River at one time, damming the water to form a large lake. The north edge of Touchet Ridge in places is very abrupt, the layers of basalt being broken square off at Milton, and marks an old fault line. North of the Ridge lies the valley of the Walla Walla River and its tribu- taries. Superposed on the old fault is a more recent fault extending from Milton about 20 miles down the valley. The basalt floor underlying the Milton-Walla Walla region has dropped 600 feet below the average gradient of the valley. The south edge of the depression lines up closely with the old fault line, while the other sides of the depression slope up gradually to surface exposures of basalt 4 miles east of Walla Walla, 6 to 8 miles north of Walla Walla, and 2 miles west of Touchet. No evidence of fracture has been found on the east, north, and west sides. "This local depression has been the site of three successive lakes, as described in a paper presented before the Northwest Science Association, December 30, 1930. Alternating layers of lake sediments and river gravels have accumulated to fill the area so that it now meets the common gradient of the valley. A fourth lake in glacial times covered the depressed area with a layer of sediments, the maximum depth of which is known to exceed 100 feet." After giving a composite log of 35 wells he states: "Most other sediments have been carried away by the Walla Walla River system. Thus, the depressed arc has been subjected to varying loads of some magnitude." Much of the descriptive matter which follows is taken from Mr. Brown's report. INTENSITY VII IN OREGON: Freewater.-Plaster and windows broken. Practically all chimneys that had been built for a period of 10 years were damaged at the roof level. Some were damaged below the roof level, but not many. Flues and walls were cracked in the Post Office Building. Two or three thousand dollars worth of damage was done to canned goods, bottled goods, furniture, fixtures, and plate glass windows at a cannery and at a drug store. Damage to school buildings amounted to about $8,500. A fine new house about 4 miles west of Freewater was almost completely wrecked. Two cement houses about 20 years old, 7 miles west of Freewater, were practically demolished. Most wells in the neighborhood of Freewater increased their flow; a few de- creased. Dry Creek, which heads about 9 miles south and east of Freewater, and which had been dry at this season in previous years, began running a very nice stream of water. Four miles west of Freewater the ground was cracked over an area 1,200 to 1,500 feet long by 50 to 100 feet wide along the base of a little hill running east to west. There were a number of little cracks running parallel to the hill. One crack some 200 or 300 feet long was from 1 to 6 feet wide. At Freewater there were 20 or more aftershocks continuing intermittently all night. State Line.-The shock was most severe here according to reports from the Milton-Freewater district. Concrete pavements were cracked. Umapine.-Many walls and chimneys were cracked and a few demolished. The upper floor of one two-story concrete house was ruined; holes appeared in the walls. One stucco house was badly damaged, and a concrete residence fell to the ground. The grade and high-school buildings, which are joined, were pulled apart about 3 inches. Well water changed. Cracks appeared in the ground ranging in size from less than pencil width to a 3-foot crack which was 8 feet deep. Large cracks appeared about 3 miles southeast of Umapine. At a ranch between Umapine and Freewater, nine cracks appeared ranging up to 6 inches in width and water was forced out of the ground in a dozen places. A large stucco farmhouse near Umapine was so badly damaged that the family moved out onto the lawn. At Umapine one observer counted the tremors the first night and reported 38 aftershocks with other very, slight quakes mixed in. For some time a few shocks occurred each night and some in the daytime. INTENSITY VI IN OREGON: Athena.-Windows and furniture broke; plaster cracked and some fell. Cornices and other light structural parts damaged. A number of chimneys down; two buildings pulled apart by the quake; one house damaged beyond repair. Ferndale.-In one house a brick chimney broke at the roof and at the ceiling. Part rotated and part fell. Milton.-A few instances of broken windows and cracked plaster; several instances of fallen plaster; a few instances of broken furniture; many chimneys cracked; few walls demolished. Two freight cars thrown off track. Some increases in well water. INTENSITY VI IN WASHINGTON: Waitsburg.-Felt by practically all; many alarmed. Small objects moved; clocks stopped; plaster cracked. Several chimneys fell. INTENSITY V IN OREGON: Arlington.-People ran out in alarm. Haines.-Water spilled northeast to southwest. Small objects not moved. Helix.-Eight shocks, the first strongest, two others severe, and the last weakest, all occurring between 23:15 and 24:00. Felt by all; awakened all; frightened few. Moved but did not overturn small objects. Plaster cracked, some fell; damage slight. Hermiston.-Three shocks. Felt by 80 percent of population; many alarmed. Some cracks in concrete cellar walls of a farmhouse 5 miles east of Hermiston. Monument.-Moved small objects and furnishings and broke dishes near Monument. Some damage on hillside farm about 7 miles south of Monument. Timbers fell in bridge under construction at Monument. Pilot Rock.-People ran out in alarm. Primeville.-Awakened few; frightened all. Furnishings moved. Umatilla.-Felt by about half of those who were at rest indoors and by about one-fifth of those who were moving about; a few ran out doors in alarm. Furniture was displaced in a few instances; clocks stopped. INTENSITY V IN WASHINGTON: Colfax.-Felt by all or nearly all; frightened few. Roaring sounds. Loose objects moved; liquids spilled. Some slight cracks in plaster and wall paper. Hooper.-Felt by practically all; several alarmed. Small objects moved. No sounds. Page.-Duration 2 minutes. Plaster cracked. Pomeroy.-Felt by nearly all; few alarmed. Small objects moved. Prescott.-Pendulum clocks did not stop. Overturned small objects. Broke plaster. Slight damage to chimneys. Prosser.-Felt by all or nearly all. Plaster cracked in a few instances. Touchet.-Felt by practically all. Small objects and furniture moved. A little fallen plaster; no other damage. Walla Walla.-One report states that the earthquake was felt by several; another, by most. Many alarmed, leaving houses for streets. Moderately loud rambling sounds immediately preceding first shock. Standing pictures were shaken down, some movable objects changed positions, doors partially opened. Shocks more noticeable on second and higher floors than on ground floors. A few chimneys and many loose chimney bricks knocked down. Five miles southwest of Walla Walla an artesian well about 600 feet deep which had weakened to the point where it was necessary to pump water from a depth of several feet renewed its flow to almost the original strength and had not diminished by October l8. About l5 or 2O slight aftershocks were felt by some in Walla Walla. Wallula.-Felt by all. Wheeler.-Preceded by load roar. All the windows rattled, and things on the wall moved about. Intensity IV in Oregon: Baker; between Courtrock, Hamilton, and Monument; Echo; Elgin; Granite; Heppner; La Grande; North Powder; Pendleton; Promise; Weston. Intensity IV in Washington: Alameda, Cedonia, Cheselah, Davenport, Day- ton, Deerpark, Entiat, Ephrata, Hanford, Harrington, Irby, Kahlotus, Klickitat County (southeast section), Lakeside, Laurier, Leavenworth, Locke, Lowden, Odessa, Okanogan, Omak, Othello, Pasco, Pateros, Pullman, Ritzville, Rosalia, Spokane, Spokane Bridge, Sprague, Starbuck, Sunnyside, Twisp, Valley, Warden, Washtucna, Wauconda, Winchester. Intensity IV in Idaho: Bovill, Coeur d'Alene, Hauser Junction, Lewiston, Moscow, Potlatch, Sandpoint, St. Maries, Troy. Intensity III and under in Oregon: Antelope, Bartlett, Bordman, Enterprise, Evans, Flora, Joseph, Paradise, Portland, Telocaset, The Dalles, Troy, Ukiah, Wellowa, Whitney, Willows. Intensity Ill and under in Washington: Adams County (southern part), Asotin, Beckleton, Bluestem, Brewster, Chattaroy, Chelan Falls, Cheney, Clay- ton, Freeman, Goldendale, Grand Coulee, Hartline, Kennewick, Lacrosse, Metta- line Falls, Mottinger, Mountain View, Nespelem, Newport, Northport, Oroville, Republic, Stehekin, Trinidad, Wahluke, Waukon, Wawawai, Wellpinit, Wenat- chee, White Salmon, White Swan, Wilbur, Wilson Creek, Winthrop, Winton, and Yakima, Intensity Ill and under in Idaho: Banners Ferry, Cameron, Cottonwood, Grangeville, Harrison, Kamiah, Kellogg, Nez Perce, Post Falls, Rathdrum. Not felt in Oregon: Huntington, Imnaha, Lake, Lookingglass, Range, Wil- lamette. Not felt in Washington: Blewett Pass, Chesaw, Colville, Conconully, Fishtrap, Hellgate, Lemanasky Lake, Lucerne, Milan, Millwood, Rimrock Dam, Rogers- burg, Ruff, Wapato. Not felt in Idaho: Caldwell, Elk City, Granite, Headquarters, Kendrick, Orofino, St. Charles, St. Joe, Southwick, Wallace, Wardner, Warren, Weiser, Winchester. July 15: 23:13. Waitsburg and Walla Walla, Wash. Slight aftershock. July 15: 23:23. Walla Walla, Wash. Aftershock. July 15: 23:25. Waitsburg, Walla Walla, and Wenatchee, Wash. Slight aftershock. July 15: 23:30. Walla Walla, Wash. Aftershock. July 15: 23:37. Athens, Oreg., and Waitsburg, Wash. Slight aftershock. July 15: 23:56. Walla Walla, Wash. Aftershock. July 15: 23:58. Sprague and Waitsburg, Wash. A few slight aftershocks. July 16: 0:10. Waitsburg and Walla Walla, Wash. Slight aftershock. July 16: 0:25. Mason City, Wash. Another series of delayed tremors which shook windows of house. Felt also at Walla Walla, Wash. July 16: 0:27 1/2. Walla Walla, Wash. Aftershock. July 16: 0:38. Walla Walla, Wash. Aftershock. July 16: 1:06. Walla Walla, Wash. Aftershock. July 16: 1:10. Walla Walla, Wash. Aftershock. July 16: 3:00. Walla Walla, Wash. Light aftershock. July 16: 4:30. Athens, Oreg. Slight aftershock. Lowden, Wash. Two small shocks felt. July 16: 8:30. Dayton, Wash.? "Other towns report a slight shock on the 16th at 8:30 a. m.-it was not noticeable here." July 17: 10:27. Mottinger, Wash. Slight aftershock. July 17: 20:30. Lowden, Wash. One small shock. July 18: 7:10. Milton-Freewater, Ore. Slight aftershock. July 18: 8:30. Milton-Freewater, Ore. V. Heaviest aftershock thus far. IV at Helix and Pendleton, Ore. and at Walla Walla, Wash. July 18: 9:30. Walla Walla, Wash. Aftershock, duration 4-5 seconds. Stove rattled. July 20: 4:10. Freewater, Ore. "Little jiggler." July 20: 9:30. Freewater, Ore. "Little jiggler." July 21: Morning. Umapine, Oreg. Eight aftershocks. No damage. July 24: Morning. Seattle, Wash. Numerous reports of a series of very slight tremors felt only in high office buildings. July 25: 0:45. Bothell and Seattle, Wash. IV. July 26: 0:00.* Seattle, Wash. Very slight. July 30: 3:20. Freewater, Ore,. IV July 30: 4:-. Freewater, Ore. IV. July 30: 4:20. Walla Walla, Wash. III or IV. August 4: 1:19. Helix, Oreg. V. Small objects moved. Quake not so strong as on July 15, but lasted longer. IV at Walla Walla, Wash., III at Colfax, Wash. August 27: 20:38. Walla Walla, Wash. IV. August 28: '-:-. Walla Walla, Wash. Aftershock. November 17: 2:00 to 2:30. Walla Walla, Wash. III. November 17: 4:-. Walla Walla, Wash. III.
UW Dept. of Earth and Space Sciences ..... . PNW EARTHQUAKES
University of Washington Dept. of Earth and Space Sciences, Box 351310 Seattle, WA, 98195-1310