The 1700 Cascadia earthquake and Japan's 'orphan' tsunami
Terremoto de Cascadia de 1700 y el tsunami «huérfano» de Japón
- Date
- 26 de enero de 1700 · confidence high
- Place
- Copalis marsh, Washington, United States
- Credited to
- Brian Atwater, Kenji Satake and colleagues
- Field
- Cosmos & Earth
What was discovered
Dead trees in marshes on the Pacific coast, dated by their rings, and Japanese records of a tsunami with no local earthquake allowed Atwater, Satake and others to date a magnitude-9 earthquake on the Cascadia subduction zone: 26 January 1700, around 9 pm. It showed that the subduction zone of the US and Canada could produce giant earthquakes.
The identification was published in 1996 (Satake et al., Nature) and 1997 (Yamaguchi et al.). Oral accounts of Native peoples of the coast agree with the date. The exact magnitude (8.7-9.2) is uncertain.
What it led to
- revision of seismic hazard in the Pacific Northwest
- use of historical documents and tree rings in palaeoseismology