Appendix A: Significant Historical Earthquakes in the Pacific Northwest
| Date | Magnitudes | Source | Comments |
|---|---|---|---|
| Jan . 26, 1700 | 9 | SZ | Dated by Japanese tsunami |
| Oct. 23, 1853 | 5.7 | ? | Eureka area, wharf sank 4 feet, intensity VII |
| Mar. 20, 1855 | ? | ? | Eureka, intensity VI, affected flow of streams |
| Jun. 14, 1857 | ? | ? | Eureka, intensity VI |
| Nov. 13, 1860 | 5.7 | ? | Humboldt Bay, chimney, plaster damage, VII |
| Oct. 29, 1864 | 5.5 | SC | Georgia Strait |
| Oct. 1, 1865 | 5.4-5.7 | ? | Eureka, fissure Ft. Humboldt, VII-VIII |
| Mar. 2, 1871 | 5.9 | ? | Petrolia, damage Rohnerville, intensity VIII |
| Dec. 15, 1872 | 6.8 | CR | Entiat, WA |
| Nov. 23, 1873 | 6.7 | SC | CA-OR border, damage to Crescent City |
| Sep. 30, 1875 | 5.8 | ? | SE of Eureka, intensity VII |
| Oct. 12, 1877 | 5.2 | CR | Portland, OR, intensity VII, 2 events |
| May 9, 1878 | 5.8 | TF | Mendocino FZ, chimneys collapsed in Petrolia, CA |
| Apr. 30, 1882 | <6? | SC? | South Puget Sound |
| Jan. 28, 1884 | 5.7 | ? | N. of Hoopa, intensity V |
| Jul. 25, 1890 | 6 | ? | Damage at Ferndale and Petrolia, CA |
| Nov. 29, 1891 | ? | ? | Puget Sound |
| Sep. 30, 1894 | 5.6-5.8 | ? | Near Miranda, S. Humboldt Co. |
| Jan. 3, 1896 | 5.3 | ? | N. Puget Sound |
| Apr. 15, 1898 | 6.8 | ? | Mendocino coast, Ft. Bragg-Greenwood, intensity IX |
| Apr. 16, 1899 | 6.4 | SO | Offshore Arcata, damage to Eureka, CA, Gorda Plate |
| Dec. 9, 1903 | ? | SO | Offshore Eureka |
| Mar. 17, 1904 | 5.3 | ? | 60 km NW Seattle, intensity VII |
| Apr. 23, 1906 | 6.4 | ? | McKinleyville, Ferndale, Eureka, Trinidad, intensity VII |
| Jan. 11, 1909 | 6 | SC | San Juan and Gulf islands, intensity VII |
| May 18, 1909 | ? | ? | Petrolia, chimneys damaged, intensity VIII |
| Oct. 28, 1909 | 6.4 | ? | Rio Dell, Rohnerville, Upper Mattole, intensity VIII |
| Mar. 19, 1910 | 6 | SO | Offshore Petrolia, intensity V |
| Aug. 22, 1914 | 6.75 | TF | Blanco Fracture Zone |
| Dec. 31, 1915 | 6.2-6.5 | ? | Offshore Cape Mendocino |
| Jun. 10, 1917 | 6.5 | TF | Blanco Fracture Zone |
| Aug. 18, 1915 | 5.6 | CR | North Cascades, VII |
| Jul. 15, 1918 | 6-6.5 | SO | Offshore Arcata, VI |
| Dec. 6, 1918 | 7 | CR | Vancouver Island W. coast |
| Sep. 15, 1919 | ? | ? | Eureka, Chimneys fell, intensity VI |
| Jan. 24, 1920 | 5.5 | SC | Georgia Strait |
| Jan. 26, 1922 | 6 | TF? | Offshore Cape Mendocino |
| Jan. 31, 1922 | 7.3-7.6 | SO | 37 mi. W of Arcata, CA, VI, felt Klamath Falls |
| Jan. 22, 1923 | 6.5-7.3 | TF | Mendocino FZ; damage at Petrolia, intensity VIII |
| Feb. 24, 1924 | 5.75 | TF | Blanco Fracture Zone |
| Jun. 4, 1925 | 6 | ? | Offshore W of Orick, CA |
| Jun. 5, 1926 | 6 | TF | Blanco Fracture Zone |
| Dec. 10, 1926 | 6 | SO | Gorda Plate, 80 mi. W of Eureka, CA |
| Feb. 9, 1928 | 5.8 | SC? | SW Vancouver Island |
| Sep. 11, 1928 | 6.3 | TF | Blanco Fracture Zone |
| May 26, 1929 | 7.0 | TF | SE end of Queen Charlotte Fracture Zone |
| Sep. 23, 1930 | 5-5.5 | ? | Chimneys fell in Eureka, VII |
| Mar. 10, 1931 | 5.6 | ? | Offshore C. Mendocino |
| Sep. 9, 1931 | 5.8 | ? | Offshore Eureka, chimneys damaged, intensity VI |
| Mar. 2, 1932 | 5.6 | TF? | 112 mi W. C. Mendocino |
| Jun. 6, 1932 | 6.4 | SC | One death at Arcata, damage at Eureka |
| Jun. 20, 1932 | 5.5 | TF | Blanco Fracture Zone |
| Jul. 17, 1932 | 5.2 | CR | Duvall, NE of Seattle, VII |
| Mar. 26, 1933 | 5.5 | TF | Blanco Fracture Zone |
| Jul. 6, 1934 | 6.5 | SO | 56 mi. W of Trinidad, CA |
| Jan. 2, 1935 | 5.8 | ? | Offshore C. Mendocino, intensity V |
| Apr. 30, 1936 | 5.5 | TF | Blanco Fracture Zone |
| Jun. 3, 1936 | 5.8 | TF? | 93 mi. W. C. Mendocino |
| Jul. 16, 1936 | 5.1-5.5 | CR | Milton-Freewater, near OR-WA border |
| Sep. 25, 1936 | 6.2 | TF | Blanco Fracture Zone |
| Nov. 5, 1936 | 6 | TF | Blanco Fracture Zone |
| Feb. 6, 1937 | 5.7-5.8 | ? | Offshore C. Mendocino, slight damage |
| Nov. 10, 1937 | 5.75 | TF | Blanco Fracture Zone |
| Aug. 3, 1938 | 5.6 | TF | Blanco Fracture Zone |
| Sep. 11, 1938 | 5.5 | ? | SE C. Mendocino, slight damage Ferndale |
| Nov. 13, 1939 | 5.5-6.2 | SC | Puget Sound region, intensity VII |
| Nov. 17, 1940 | 6 | TF | Blanco Fracture Zone |
| Nov. 19, 1940 | 5.5 | ? | Offshore C. Mendocino, slight damage |
| Feb. 9, 1941 | 6.4-6.6 | SO | 60 mi. W of Eureka, NW C. Mendocino |
| May 13, 1941 | 6 | ? | Offshore C. Mendocino |
| Oct. 2, 1941 | 6.4 | SC | 30 mi. W of C. Mendocino |
| Oct. 31, 1941 | 5.5 | TF | Blanco Fracture Zone |
| Mar. 6, 1944 | 5.75 | TF | Blanco Fracture Zone |
| Dec. 30, 1944 | 5.75 | TF | Blanco Fracture Zone |
| Apr. 29, 1945 | 5.9 | CR | 50 km SE of Seattle, intensity VII |
| May 19, 1945 | 6.2 | ? | Offshore C. Mendocino |
| Feb. 15, 1946 | 5.6-6.4 | SC | Puget Sound region |
| Jun. 23, 1946 | 7.3 | CR | Central Vancouver Island |
| Sep. 23, 1947 | 5.6 | ? | Offshore C. Mendocino, intensity VII |
| May 25, 1948 | 5.5 | TF | Blanco Fracture Zone |
| May 25, 1948 | 5.8 | TF | Blanco Fracture Zone |
| Mar. 24, 1949 | 5.9 | SO | 93 mi. W of Orick |
| Apr. 13, 1949 | 7.1 | SC | Olympia, WA, intensity VIII |
| Aug. 22, 1949 | 8.1 | TF | Queen Charlotte Fracture Zone |
| Aug. 24, 1949 | 5.5 | TF | Blanco Fracture Zone |
| Feb. 23, 1951 | 5.6 | TF | Blanco Fracture Zone |
| Jun. 16, 1951 | 5.5 | TF | Blanco Fracture Zone |
| Jun. 17, 1951 | 6 | TF | Blanco Fracture Zone |
| Oct. 8, 1951 | 5.8-6 | TF | 10 mi W Petrolia; 6 mi W of Punta Gorda |
| Aug. 20, 1952 | 6 | TF | Blanco Fracture Zone |
| Nov. 25, 1954 | 6.1-6.3 | TF | 65 mi. W Punta Gorda, Mendocino Fracture Zone |
| Dec. 21, 1954 | 6.5-6.6 | CR | $3.1 million damage, 1 death, 12 mi NE Arcata |
| Aug. 23, 1955 | 6.25 | TF | Blanco Fracture Zone |
| Feb. 19, 1956 | 6.8 | SO | Pacific Plate NW of Vancouver Is. |
| Oct. 11, 1956 | 6 | ? | NW of C. Mendocino, slight damage Ferndale |
| Dec. 21, 1956 | 6.7 | SO | small plate near Queen Charlotte Fracture Zone |
| Dec. 16, 1957 | 5.9 | SO | W. of Vancouver Is., NE of Nootka Fault |
| Jul. 23, 1959 | 5.8 | SO | 56 mi. W Trinidad, CA |
| Aug. 5, 1959 | 5-5.5 | CR | near Chelan, WA, intensity VI |
| Sep. 26, 1959 | 6.1 | TF | Blanco Fracture Zone |
| Jun. 5, 1960 | 5.7 | SO | Offshore Arcata, intensity VI |
| Aug. 9, 1960 | 6-6.2 | TF | Felt S. OR to San Francisco |
| Apr. 6. 1961 | 5-5.5 | TF | 11 mi W C. Mendocino, landslides |
| Aug. 23, 1962 | 5.6 | SO | Offshore Crescent City |
| Nov. 5, 1962 | 5.2-5.5 | CR | OR-WA border near Portland, OR, VII |
| Jul. 13, 1964 | 5.5 | TF | Blanco Fracture Zone |
| Oct. 1, 1964 5.5 | 5.5 | TF | Blanco Fracture Zone |
| Oct. 29, 1964 | 5.5 | SC | Georgia Strait |
| Apr. 29, 1965 | 6.5 | SC | Seattle, WA, intensity VIII |
| May 31, 1965 | 5.5 | TF | Blanco Fracture Zone |
| Dec. 10, 1967 | 5.6-5.8 | TF | 12 mi. W. of Petrolia, CA, slight damage |
| May 8, 1968 | 6.1 | TF | Blanco Fracture Zone |
| Jun. 26, 1968 | 5.5-5.9 | TF | Offshore C. Mendocino |
| May 8, 1969 | 5.5 | TF | Blanco Fracture Zone |
| Jun. 24, 1970 | 7.4 | TF? | Queen Charlotte TF or N. America Plate |
| Nov. 26, 1970 | 6 | TF | Blanco Fracture Zone |
| Mar. 13, 1971 | 6.1 | SO | W. of Vancouver Island |
| Jul. 23, 1972 | 6.4 | SO | W. of Vancouver Island |
| Jun. 7, 1975 | 5.2-5.7 | SC | Fortuna, CA |
| Nov. 26, 1976 | 6.3 | SO | Gorda Plate, 93 mi. NW of Eureka |
| Dec. 9, 1976 | 5.5 | TF | Blanco Fracture Zone |
| Dec. 20, 1976 | 6.7 | SO | W. of Vancouver Is. |
| Jun. 2, 1978 | 5.5 | CR | Brooks Peninsula, NW Vancouver Is. |
| Jul. 25, 1978 | 5.5 | CR | Brooks Peninsula, NW Vancouver Is. |
| May 18, 1980 | 5.1 | CR | Eruption of Mt. St. Helens |
| Nov. 8, 1980 | 6.9-7.4 | SO | 30 mi. W Trinidad, $1.75 million damage |
| Dec. 17, 1980 | 6.8 | SO | W. of Vancouver Is. |
| Feb. 14, 1981 | 5.5 | CR | Elk Lake, WA on St. Helens seismic zone |
| Nov. 3, 1981 | 6.4 | TF | Blanco Fracture Zone |
| Aug. 24, 1983 | 5.5 | TF | Offshore C. Mendocino |
| Sep. 10, 1984 | 6.6 | TF | 166 mi W of Eureka, felt OR to San Francisco |
| Mar. 13, 1985 | 6.3 | TF | Blanco Fracture Zone |
| Jul. 31, 1987 | 5.5 | SO or SC | Just off C. Mendocino |
| Oct. 23, 1988 | 5.5 | TF | Blanco Fracture Zone |
| Jul 13, 1991 | 6.7-6.9 | SO | 50 mi WNW of Crescent City |
| Aug. 16, 1991 | 5.9-6.3 | SO | 62 mi W of Crescent City |
| Aug. 17, 1991 | 6.2 | CR | Honeydew, CA, chimney, foundation damage |
| Aug. 17, 1991 | 6.9-7.1 | SO | 62 mi W of Crescent City |
| Mar. 7, 1992 | 5.3-5.6 | CR | S. of Petrolia, landslides, foundation damage |
| Apr. 6, 1992 | 6.8 | TF | W. Vancouver Is., Revere-Dellwood-Wilson Fracture Zone |
| Apr. 25, 1992 | 7.1 | SZ | Tsunami, coastal uplift, $48 million damage |
| Apr. 26, 1992 | 6.6 | SO | 17 mi. WNW Petrolia, damage to Scotia |
| Apr. 26, 1992 | 6.7 | SO | 16 mi. W Petrolia, added damage |
| Aug. 21, 1992 | 5.5 | TF | Blanco Fracture Zone |
| Mar. 25, 1993 | 5.6 | CR | Scotts Mills, OR, E of Salem |
| Apr. 26, 1993 | 6.5 | SO | 15 mi W of Petrolia |
| Sep. 20, 1993 | 6 | TF | Mendocino Fracture Zone, 85 mi W C. Mendocino |
| Sep. 20, 1993 | 5.9, 6 | CR | 2 eqs. W. Klamath Falls, OR |
| Sep. 1, 1994 | 6.9-7.2 | TF | 88 mi. W C. Mendocino, felt OR to San Francisco |
| Oct. 27, 1994 | 5.6 | TF | Blanco Fracture Zone |
| Feb. 18, 1995 | 6.6 | SO | 88 mi. WSW Eureka |
| Jul. 24, 1996 | 6 | SO | 115 mi. W Crescent City |
| Jan. 21, 1997 | 5.7 | TF | 1 mi NW of Punta Gorda |
| Oct. 4, 1997 | 5.7 | SO | 65 mi. W Trinidad, CA |
| Nov. 27, 1998 | 5.6 | SO | 60 mi. W Ferndale, CA |
| Jul. 2, 1999 | 5.8 | SC | Satsop, WA |
| Jan. 20, 2000 | 6.1 | TF | Blanco Fracture Zone |
| Mar. 16, 2000 | 5.9 | TF | 52 mi W Petrolia |
| Jun. 2, 2000 | 6.2 | TF | Blanco Fracture Zone |
| Jan. 13, 2001 | 5.6 | SO | 62 mi. W Eureka |
| Feb. 28, 2001 | 6.8 | SC | Nisqually Earthquake, S. Puget Sound, VII-VIII |
| Jul. 9, 2002 | 6 | TF | Blanco Fracture Zone |
| Sep. 2, 2002 | 5.7 | TF | Blanco Fracture Zone |
| Jan. 16, 2003 | 6.2 | TF | Blanco Fracture Zone |
| Nov. 19, 2007 | 5.8 | TF | Blanco Fracture Zone |
| Mar. 30, 2008 | 5 | TF | Blanco Fracture Zone (swarm) |
| Mar. 8, 2011 | 5.0 | TF | Blanco Fracture Zone |
| Oct. 27, 2012 | 7.8 | TF | Queen Charlotte Fracture Zone |
| Apr. 24, 2014 | 4.8 | TF | Queen Charlotte Fracture Zone |
| Nov. 27, 2014 | 4 | CR | Sheldon Wildlife Refuge, NV (swarm) |
| Jan. 28, 2015 | 5.7 | TF | Mendocino Fracture Zone |
Magnitudes for pre-seismograph earthquakes are corrected intensity magnitudes where available. Key to source: CR, crustal; SO, slab, offshore; SC, slab, beneath the continent; SZ, subduction zone; TF, transform fault
