Where and when were the largest earthquakes in the USA?

The ten largest earthquakes in the United States

# Magnitude Date (UTC) Location
1. 9.2 March 28, 1964 Prince William Sound, Alaska
2. 8.8 March 9, 1957 Andreanof Islands, Alaska
3. 8.7 February 4, 1965 Rat Islands, Alaska
4. 8.3 November 10, 1938 East of Shumagin Islands, Alaska
8.3 July 10, 1958 Lituya Bay, Alaska
6. 8.2 September 10, 1899 Yakutat Bay, Alaska
8.2 September 4, 1899 near Cape Yakataga, Alaska
8. 8.0 May 7, 1986 Andreanof Islands, Alaska
9. 7.9 February 7, 1812 New Madrid, Missouri
7.9 January 9, 1857 Fort Tejon, California
7.9 April 3, 1868 Ka'u District, Island of Hawaii
7.9 October 9, 1900 Kodiak Island, Alaska
7.9 November 30, 1987 Gulf of Alaska

The ten largest earthquakes in the Contiguous United States

# Magnitude Date (UTC) Location
1. 7.9 February 7, 1812 New Madrid, Missouri
7.9 January 9, 1857 Fort Tejon, California
3. 7.8 March 26, 1872 Owens Valley, California
7.8 February 24, 1892 Imperial Valley, California
5. 7.7 December 16, 1811(0815) New Madrid, Missouri area
7.7 April 18, 1906 San Francisco, California
7.7 October 3, 1915 Pleasant Valley, Nevada
8. 7.6 January 23, 1812 New Madrid, Missouri
9. 7.5 July 21, 1952 Kern County, California
10. 7.3 November 4, 1927 West of Lompoc, California
7.3 December 16, 1954 Dixie Valley, Nevada
7.3 August 18, 1959 Hebgen Lake, Montana
7.3 October 28, 1983 Borah Peak, Idaho

Note: Widely differing magnitudes have been computed for some of these earthquakes; the values differ according to the methods and data used. For example, some sources list the magnitude of the 8.7 Rat Islands earthquake as low as 7.7. On the other hand, some sources list the magnitude of the February 7, 1812 New Madrid quake as high as 8.8.

Similar variations exist for most events on this list, although generally not so large as for the examples given. In general, the magnitudes given in the list above have been determined from the seismic moment, when available. For very large earthquakes, the moment magnitude is considered to be a more accurate determination than the traditional amplitude magnitude computation procedures. Note that all of these values can be called "magnitudes on the Richter scale," regardless of the method used to compute them.

Source:

URL: http://eqinfo.ucsd.edu/faq/big_eqs.php [Last updated: 2015-10-22 (295) 23:07:44 UTC]