Atwater has spent much of his career studying the likelihood of large earthquakes and tsunamis in the Pacific Northwest region of North America . In 2005 , he published a book with others , " The Orphan Tsunami of 1700 , " that summarizes the evidence for an 8.7 – 9.2 megathrust earthquake in the Pacific Northwest on 26 January 1700 , known as the 1700 Cascadia earthquake . The earthquake produced a tsunami so large that contemporary reports in Japan noted it , allowing Atwater 's team to assign a precise date and approximate magnitude to the earthquake . Its occurrence and size are confirmed by evidence of a dramatic drop in the elevation of Northwest coastal land , recorded by buried marsh and forest soils that underlie tidal sediment , the deposition of a layer of tsunami sand on the subsided landscape , the death or injury of affected trees ( see dendrochronology ) , and descriptions of the earthquake and tsunami in regional Amerindian legends
1700 Cascadia earthquake
1700 Cascadia earthquake
Brian Atwater