Largest Earthquakes by State
List of Earthquakes
All earthquake dates are UTC, not local time.
For each state, the following list gives the largest historical earthquake that had its epicenter in that state. The earthquakes are those with the highest magnitudes, as measured from seismographs or as inferred from the intensities produced by the earthquakes. The time periods for which there are complete records of large earhquakes varies from about three centuries in some eastern states to slightly more than a century in some western states. Be aware that the highest historical intensities in some states did not come from shocks that had their epicenters within the states' borders, but rather from earthquakes whose epicenters were in nearby states.
| State | Date | Time | Location | Magnitude | Intensity | |
|---|---|---|---|---|---|---|
| UTC | Latitude | Longitude | ||||
| Alabama | 1916 10 18 | 22:04 | 33.5N | 86.5W | 5.1 | VII |
| Alaska | 1964 03 28 | 03:36:14.0 | 61.04N | 147.73W | 9.2 | X |
| Arizona | 1959 07 21 | 17:39:29 | 36.80N | 112.37W | 5.6 | VI |
| Arkansas | 1811 12 16 | 08:15 | 35.6N | 90.4W | ~8.2 - 8.1 | XI |
| California | 1857 01 09 | 16:24 | 35.7N | 120.3W | 7.9 | IX |
| California | 1906 04 18 | 13:12:21 | 37.75N | 122.55W | 7.8 | XI |
| Colorado | 1882 11 08 | 01:30 | 40.5N | 105.5W | 6.2 | VII |
| Connecticut | 1791 05 16 | 13:00 | 41.5N | 72.5W | VII | |
| Delaware | 1871 10 09 | 14:40 | 39.7N | 75.5W | VII | |
| Florida | 1780 02 06 | 30.4N | 87.2W | VI | ||
| Florida | 1879 01 13 | 04:45 | 29.5N | 82.0W | VI | |
| Georgia | 1914 03 05 | 20:05 | 33.5N | 83.5W | 4.5 | V |
| Hawaii | 1868 04 03 | 02:25 | 19.0N | 155.5W | 7.9 | X |
| Idaho | 1983 10 28 | 14:06:06.5 | 43.974N | 113.916W | 6.9 | IX |
| Illinois | 1968 11 09 | 17:01:40.5 | 37.911N | 88.373W | 5.4 | VII |
| Illinois | 2008 04 18 | 09:36:59.1 | 38.452N | 87.886W | 5.4 | VII |
| Indiana | 1909 09 27 | 09:45 | 39.8N | 87.2W | 5.1 | VII |
| Iowa | 1905 04 13 | 16:30 | 40.4N | 91.4W | V | |
| Kansas | 1867 04 24 | 20:22 | 39.2N | 96.3W | 5.1 | VII |
| Kentucky | 1980 07 27 | 18:52:21.4 | 38.193N | 83.891W | 5.2 | VII |
| Louisiana | 1930 10 19 | 12:17 | 30.0N | 91.0W | 4.2 | VI |
| Maine | 1904 03 21 | 06:04 | 45.0N | 67.2W | 5.1 | VII |
| Maryland | 1990 01 13 | 20:47:55.3 | 39.425N | 76.881W | 2.6 | V |
| Massachusetts | 1755 11 18 | 09:11:35 | 42.7N | 70.3W | VIII | |
| Michigan | 1947 08 10 | 02:46:41.3 | 41.928N | 85.004W | 4.6 | VI |
| Minnesota | 1975 07 09 | 14:54:15.1 | 45.669N | 96.041W | 4.6 | VI |
| Mississippi | 1931 12 17 | 03:36 | 33.8N | 90.1W | 4.6 | VI |
| Missouri | 1812 02 07 | 09:45 | 36.5N | 89.6W | ~7.4 - 8.0 | XII |
| Montana | 1959 08 18 | 06:37:13.5 | 44.712N | 111.215W | 7.3 | X |
| Nebraska | 1877 11 15 | 17:45 | 41.0N | 97.0W | 5.1 | VII |
| Nebraska | 1964 03 28 | 10:08:46.5 | 42.997N | 101.798W | 5.1 | VII |
| Nevada | 1932 12 21 | 06:10:05 | 38.51N | 118.08W | 7.2 | X |
| New Hampshire | 1940 12 20 | 07:27:26.2 | 43.872N | 71.370W | 5.5 | VII |
| New Hampshire | 1940 12 24 | 13:43:45.0 | 43.908N | 71.283W | 5.5 | VII |
| New Jersey | 1783 11 30 | 03:50 | 41.0N | 74.5W | 5.3 | VI |
| New Mexico | 1906 11 15 | 12:15 | 34.0N | 107.0W | VII | |
| New York | 1944 09 05 | 04:38:45.7 | 44.958N | 74.723W | 5.8 | VIII |
| North Carolina | 1916 02 21 | 23:39 | 35.5N | 82.5W | 5.2 | VII |
| North Dakota | 1909 05 16 | 04:15 | 49.0N | 104.0W | 5.5 | VI |
| Ohio | 1937 03 09 | 05:44:35.5 | 40.470N | 84.280W | 5.4 | VIII |
| Oklahoma | 1952 04 09 | 16:29:28.4 | 35.525N | 97.850W | 5.5 | VII |
| Oregon | 1910 08 05 | 01:31:36 | 42.0N | 127.0W | 6.8 | Felt |
| Oregon | 1993 09 21 | 03:28:55.4 | 42.314N | 122.012W | 6.0 | VII |
| Pennsylvania | 1998 09 25 | 19:52:52.1 | 41.495N | 80.388W | 5.2 | VI |
| Rhode Island | 1976 03 11 | 08:29:32.2 | 41.56N | 71.21W | 3.5 | VI |
| South Carolina | 1886 09 01 | 02:51 | 32.9N | 80.0W | 7.3 | X |
| South Dakota | 1911 06 02 | 22:34 | 44.2N | 98.2W | 4.5 | V |
| Tennessee | 1865 08 17 | 15:00 | 36.0N | 89.5W | 5.0 | VII |
| Texas | 1931 08 16 | 11:40:22.3 | 30.502N | 104.575W | 5.8 | VIII |
| Utah | 1934 03 12 | 15:05:40 | 41.7N | 112.8W | 6.6 | VIII |
| Vermont | 1962 04 10 | 14:30:45.2 | 44.114N | 72.972W | 4.2 | V |
| Virginia | 1897 05 31 | 18:58 | 37.3N | 80.7W | 5.9 | VIII |
| Washington | 1872 12 15 | 05:40 | 47.9N | 120.3W | 6.8 | IX |
| West Virginia | 1969 11 20 | 01:00:09.3 | 37.449N | 80.932W | 4.5 | VI |
| Wisconsin | 1947 05 06 | 21:27 | 43.00N | 87.90W | V | |
| Wyoming | 1959 08 18 | 07:56:16.8 | 44.699N | 110.705W | 6.5 | Felt |
Explanation
Most of the earthquakes listed in "The Largest Earthquakes, State by State" are those with the largest magnitudes for each state listed in the work of Carl W. Stover and Jerry L. Coffman, 1993, Seismicity of the United States, 1568-1989 (Revised), U.S. Geological Survey Professional Paper 1527. Data on post-1989 earthquakes and on earthquakes too small to be included in the study of Stover and Coffman (they considered earthquakes with magnitudes of 4.5 or greater, or with intensities of VI or greater) come from other publications of the U.S. Geological Survey and the U.S. Coast and Geodetic Survey.
Not all the pre-instrumental earthquakes listed in Stover and Coffman have magnitude estimates associated with them, and in some cases a pre-instrumental earthquake is listed as largest if the characteristics of its intensity distribution (e.g., maximum intensity and area over which the earthquake was felt) imply that the earthquake would have had a higher magnitude than any other earthquake in the state.
For some states, the two largest earthquakes are listed, if the data listed in Stover and Coffman's study imply that the shocks were of nearly equal size.
Two earthquakes of different magnitude are listed for Oregon: the 1910 earthquake was the largest historical shock within the state's boundaries, but it occurred too far offshore to cause damage, whereas the damaging 1993 earthquake was the largest historical earthquake beneath the land area of Oregon.
