<P> Listed below are all known earthquakes measured or estimated to have a magnitude of 8.5 or above on the moment magnitude or Richter magnitude scale . </P> <P> This list is biased towards recent years due to development and widespread deployment of seismometers . Also, records that were detailed enough to make magnitude estimates (est .) were not generally available before 1900 . </P> <Table> <Tr> <Th> Rank </Th> <Th> Date </Th> <Th> Location </Th> <Th> Event </Th> <Th> Magnitude </Th> </Tr> <Tr> <Th> </Th> <Td> 000000001960 - 05 - 22 - 0000 May 22, 1960 </Td> <Td> Valdivia, Chile </Td> <Td> 1960 Valdivia earthquake </Td> <Td> 9.4--9.6 </Td> </Tr> <Tr> <Th> </Th> <Td> 000000001964 - 03 - 27 - 0000 March 27, 1964 </Td> <Td> Prince William Sound, Alaska, United States </Td> <Td> 1964 Alaska earthquake </Td> <Td> 9.2 </Td> </Tr> <Tr> <Th> </Th> <Td> 000000002004 - 12 - 26 - 0000 December 26, 2004 </Td> <Td> Indian Ocean, Sumatra, Indonesia </Td> <Td> 2004 Indian Ocean earthquake </Td> <Td> 9.1--9.3 </Td> </Tr> <Tr> <Th> </Th> <Td> 000000002011 - 03 - 11 - 0000 March 11, 2011 </Td> <Td> Pacific Ocean, Tōhoku region, Japan </Td> <Td> 2011 Tōhoku earthquake </Td> <Td> 9.1 </Td> </Tr> <Tr> <Th> 5 </Th> <Td> 000000001952 - 11 - 04 - 0000 November 4, 1952 </Td> <Td> Kamchatka, Russian SFSR, Soviet Union </Td> <Td> 1952 Kamchatka earthquakes </Td> <Td> 9.0 </Td> </Tr> <Tr> <Th> 6 </Th> <Td> 000000001868 - 08 - 13 - 0000 August 13, 1868 </Td> <Td> Arica, Chile (then Peru) </Td> <Td> 1868 Arica earthquake </Td> <Td> 8.5--9.0 (est .) </Td> </Tr> <Tr> <Th> 7 </Th> <Td> 000000001700 - 01 - 26 - 0000 January 26, 1700 </Td> <Td> Pacific Ocean, USA and Canada (then claimed by the Spanish Empire and the British Empire) </Td> <Td> 1700 Cascadia earthquake </Td> <Td> 8.7--9.2 (est .) </Td> </Tr> <Tr> <Th> 8 </Th> <Td> 000000000869 - 07 - 09 - 0000 July 9, 869 </Td> <Td> Pacific Ocean, Tōhoku region, Japan </Td> <Td> 869 Sanriku earthquake </Td> <Td> 8.9 (est .) </Td> </Tr> <Tr> <Th> 9 </Th> <Td> 000000001762 - 04 - 02 - 0000 April 2, 1762 </Td> <Td> Chittagong, Bangladesh (then Kingdom of Mrauk U) </Td> <Td> 1762 Arakan earthquake </Td> <Td> 8.8 (est .) </Td> </Tr> <Tr> <Th> 10 </Th> <Td> 000000001833 - 11 - 25 - 0000 November 25, 1833 </Td> <Td> Sumatra, Indonesia (then part of the Dutch East Indies) </Td> <Td> 1833 Sumatra earthquake </Td> <Td> 8.8 (est .) </Td> </Tr> <Tr> <Th> 11 </Th> <Td> 000000001906 - 01 - 31 - 0000 January 31, 1906 </Td> <Td> Ecuador--Colombia </Td> <Td> 1906 Ecuador--Colombia earthquake </Td> <Td> 8.8 </Td> </Tr> <Tr> <Th> 12 </Th> <Td> 000000002010 - 02 - 27 - 0000 February 27, 2010 </Td> <Td> Offshore Maule, Chile </Td> <Td> 2010 Chile earthquake </Td> <Td> 8.8 </Td> </Tr> <Tr> <Th> 13 </Th> <Td> 000000001950 - 08 - 15 - 0000 August 15, 1950 </Td> <Td> Assam, India--Tibet, China </Td> <Td> 1950 Assam--Tibet earthquake </Td> <Td> 8.7 </Td> </Tr> <Tr> <Th> 14 </Th> <Td> 000000001707 - 10 - 28 - 0000 October 28, 1707 </Td> <Td> Pacific Ocean, Shikoku region, Japan </Td> <Td> 1707 Hōei earthquake </Td> <Td> 8.7--9.3 (est .) </Td> </Tr> <Tr> <Th> 15 </Th> <Td> 000000001730 - 07 - 08 - 0000 July 8, 1730 </Td> <Td> Valparaiso, Chile (then part of the Spanish Empire) </Td> <Td> 1730 Valparaiso earthquake </Td> <Td> 8.7 (est .) </Td> </Tr> <Tr> <Th> 16 </Th> <Td> 000000001755 - 11 - 01 - 0000 November 1, 1755 </Td> <Td> Atlantic Ocean, Lisbon, Portugal </Td> <Td> 1755 Lisbon earthquake </Td> <Td> 8.5--9.0 </Td> </Tr> <Tr> <Th> 17 </Th> <Td> 000000001965 - 02 - 04 - 0000 February 4, 1965 </Td> <Td> Rat Islands, Alaska, United States </Td> <Td> 1965 Rat Islands earthquake </Td> <Td> 8.7 </Td> </Tr> <Tr> <Th> 18 </Th> <Td> 000000001746 - 10 - 28 - 0000 October 28, 1746 </Td> <Td> Lima, Peru (then part of the Spanish Empire) </Td> <Td> 1746 Lima--Callao earthquake </Td> <Td> 8.6 (est .) </Td> </Tr> <Tr> <Th> 19 </Th> <Td> 000000001787 - 03 - 28 - 0000 March 28, 1787 </Td> <Td> Oaxaca, Mexico (then part of the Spanish Empire) </Td> <Td> 1787 Mexico earthquake </Td> <Td> 8.6 (est .) </Td> </Tr> <Tr> <Th> 20 </Th> <Td> 000000001957 - 03 - 09 - 0000 March 9, 1957 </Td> <Td> Andreanof Islands, Alaska, United States </Td> <Td> 1957 Andreanof Islands earthquake </Td> <Td> 8.6 </Td> </Tr> <Tr> <Th> 21 </Th> <Td> 000000002005 - 03 - 28 - 0000 March 28, 2005 </Td> <Td> Sumatra, Indonesia </Td> <Td> 2005 Nias--Simeulue earthquake </Td> <Td> 8.6 </Td> </Tr> <Tr> <Th> 22 </Th> <Td> 000000002012 - 04 - 11 - 0000 April 11, 2012 </Td> <Td> Indian Ocean, Sumatra, Indonesia </Td> <Td> 2012 Aceh earthquake </Td> <Td> 8.6 </Td> </Tr> <Tr> <Th> 23 </Th> <Td> 000000001575 - 12 - 16 - 0000 December 16, 1575 </Td> <Td> Valdivia, Chile (then part of the Spanish Empire) </Td> <Td> 1575 Valdivia earthquake </Td> <Td> 8.5 (est .) </Td> </Tr> <Tr> <Th> 24 </Th> <Td> 000000001604 - 11 - 24 - 0000 November 24, 1604 </Td> <Td> Arica, Chile (then part of the Spanish Empire) </Td> <Td> 1604 Arica earthquake </Td> <Td> 8.5 (est .) </Td> </Tr> <Tr> <Th> 25 </Th> <Td> 000000001647 - 05 - 13 - 0000 May 13, 1647 </Td> <Td> Santiago, Chile (then part of the Spanish Empire) </Td> <Td> 1647 Santiago earthquake </Td> <Td> 8.5 (est .) </Td> </Tr> <Tr> <Th> 26 </Th> <Td> 000000001751 - 05 - 24 - 0000 May 24, 1751 </Td> <Td> Concepción, Chile (then part of the Spanish Empire) </Td> <Td> 1751 Concepción earthquake </Td> <Td> 8.5 (est .) </Td> </Tr> <Tr> <Th> 27 </Th> <Td> 000000001822 - 11 - 19 - 0000 November 19, 1822 </Td> <Td> Valparaíso, Chile </Td> <Td> 1822 Valparaíso earthquake </Td> <Td> 8.5 (est .) </Td> </Tr> <Tr> <Th> 28 </Th> <Td> 000000001835 - 02 - 20 - 0000 February 20, 1835 </Td> <Td> Concepción, Chile </Td> <Td> 1835 Concepción earthquake </Td> <Td> 8.5 (est .) </Td> </Tr> <Tr> <Th> 29 </Th> <Td> 000000001861 - 02 - 16 - 0000 February 16, 1861 </Td> <Td> Sumatra, Indonesia </Td> <Td> 1861 Sumatra earthquake </Td> <Td> 8.5 </Td> </Tr> <Tr> <Th> 30 </Th> <Td> 000000001877 - 05 - 09 - 0000 May 9, 1877 </Td> <Td> Iquique, Chile (then Peru) </Td> <Td> 1877 Iquique earthquake </Td> <Td> 8.5 (est .) </Td> </Tr> <Tr> <Th> 31 </Th> <Td> 000000001922 - 11 - 10 - 0000 November 10, 1922 </Td> <Td> Atacama Region, Chile Catamarca Province, Argentina </Td> <Td> 1922 Vallenar earthquake </Td> <Td> 8.5 </Td> </Tr> <Tr> <Th> 32 </Th> <Td> 000000001938 - 02 - 01 - 0000 February 1, 1938 </Td> <Td> Banda Sea, Indonesia (then part of the Dutch East Indies) </Td> <Td> 1938 Banda Sea earthquake </Td> <Td> 8.5 </Td> </Tr> <Tr> <Th> 33 </Th> <Td> 000000001963 - 10 - 13 - 0000 October 13, 1963 </Td> <Td> Kuril Islands, Russia (USSR) </Td> <Td> 1963 Kuril Islands earthquake </Td> <Td> 8.5 </Td> </Tr> <Tr> <Th> 34 </Th> <Td> 000000002007 - 09 - 12 - 0000 September 12, 2007 </Td> <Td> Sumatra, Indonesia </Td> <Td> 2007 Sumatra earthquakes </Td> <Td> 8.5 </Td> </Tr> <Tr> <Th> 35 </Th> <Td> 000000001687 - 10 - 20 - 0000 October 20, 1687 </Td> <Td> Lima, Peru (then part of the Spanish Empire) </Td> <Td> 1687 Peru earthquake </Td> <Td> 8.5 (est .) </Td> </Tr> <Tr> <Th> 36 </Th> <Td> 000000001737 - 10 - 17 - 0000 October 17, 1737 </Td> <Td> Kamchatka, Russia </Td> <Td> 1737 Kamchatka earthquakes </Td> <Td> 8.5 (est .) </Td> </Tr> <Tr> <Th> 37 </Th> <Td> 000000001361 - 08 - 03 - 0000 August 3, 1361 </Td> <Td> Pacific Ocean, Shikoku region, Japan </Td> <Td> 1361 Shōhei earthquake </Td> <Td> 8.5 (est .) </Td> </Tr> <Tr> <Th> 38 </Th> <Td> 000000001896 - 06 - 15 - 0000 June 15, 1896 </Td> <Td> Pacific Ocean, Tōhoku region, Japan </Td> <Td> 1896 Sanriku earthquake </Td> <Td> 8.5 (est .) </Td> </Tr> </Table> <Tr> <Th> Rank </Th> <Th> Date </Th> <Th> Location </Th> <Th> Event </Th> <Th> Magnitude </Th> </Tr>

What's the largest earthquake in the united states