| Saguenay, Quebec earthquake (Canada) | 3 |
| Sakata, Japan earthquake, Oct. 22, 1894 | 1 |
| San Bernardino County, California earthquake, Dec. 8, 1812 | 1 |
| San Fernando, California earthquake, Feb. 9, 1971 | 1010 |
| San Francisco, California earthquake, April 18, 1906 | 302 |
| San Jacinto, California earthquake, April 21, 1918 | 4 |
| San Jose, California earthquake, Sept. 4, 1955 | 1 |
| San Jose, Costa Rica earthquake, Dec. 30, 1888 | 3 |
| San Jose, Costa Rica earthquake, Sept. 2, 1841 | 1 |
| San Juan, Argentina earthquake, Jan. 15, 1944 | 2 |
| San Lorenzo Island, Peru earthquake, Oct. 28, 1746 | 1 |
| San Salvador, El Salvador earthquake, Apr. 14, 1854 | 2 |
| San Salvador, El Salvador earthquake, Mar. 4, 1873 | 7 |
| San Salvador, El Salvador earthquake, Oct. 10, 1986 | 70 |
| San Severo (Apulia), Italy earthquake, July 30, 1627 | 5 |
| San Simeon, California earthquake, Dec. 22, 2003 | 18 |
| Sanriku Tsunami, March 3, 1933 | 2 |
| Santa Barbara, California earthquake, Aug. 13, 1978 | 41 |
| Santa Barbara, California earthquake, June 29, 1925 | 45 |
| Santa Cruz Mountains, California earthquake, Oct. 8, 1865 | 6 |
| Santa Luce (Tuscany), Italy earthquake, Aug. 14, 1846 | 3 |
| Santa Rosa, California earthquake, Oct. 1, 1969 | 98 |
| Santorini (Thera), Greece eruption, Jan. 26, 1866 | 3 |
| Sanzal, Afghanistan earthquake, Dec. 20, 1898 | 2 |
| Sao Miguel Island, Azores earthquakes, July 26-Aug. 12, 1591 | 1 |
| Sea of Marmara, Turkey earthquake, Sept. 10(?), 1509 | 2 |
| Seattle, Washington earthquake, Apr. 13, 1949 | 33 |
| Shemakha, Azerbaijan earthquake, Feb 13, 1902 | 3 |
| Shizuoka, Japan earthquake, July 11, 1935 | 1 |
| Siberian earthquake, 1865 | 1 |
| Sichuan, China Earthquake of April 20, 2013 | 1 |
| Siena, Italy earthquake, Sept. 3, 1467 | 1 |
| Sierra Madre, California earthquake, June 28, 1991 | 3 |
| Skopje, Yugoslavia earthquake, July 26, 1963 | 9 |
| Sonora, Mexico earthquake, May 3, 1887 | 14 |
| Soufriere Guadeloupe eruption, Dec. 3, 1837 | 1 |
| South Island, New Zealand earthquake, Feb. 21, 2011 | 13 |
| South Napa Earthquake of 24 August 2014 | 1 |
| Southern Sonoma County, California earthquake, March 31, 1898 | 6 |
| Sparta, Greece earthquake, 464 B.C. | 1 |
| Spitak, Armenia earthquake, Dec. 7, 1988 | 5 |
| St. Thomas, Virgin Islands earthquake, Nov. 18, 1867 | 1 |
| Steiermark, Austria earthquake, April 29, 1899 | 1 |
| Strzelin (Silesia), Poland earthquake, June 11, 1895 | 3 |
| Sumatra, Indonesia earthquake, Feb. 16, 1861 | 1 |
| Superstition Hills, California earthquake, Nov. 24, 1987 | 3 |
| Swansea, Wales earthquake, June 27, 1906 | 1 |