What is the evidence for a Giant earthquake and Tsunami?
Ghost forests are part of the evidence that a Great earthquake and devastating tsunami occurred last on January 26th, 1700 in the Pacific Northwest.
This simplified animation illustrates both the subduction-zone processes that lead to a "ghost forest" as well as the evidence that scientists collected to determine that the Pacific Northwest has had many great earthquakes and tsunamis in the past, and will again in the future.
This is based on the work of Brian Atwater who published his findings in the the book "The Orphan Tsunami of 1700" (USGS Professional Paper 1707) available online.
Tree drowning sequence of graphics is from the book, "At Risk: Earthquakes and Tsunamis on the West Coast ", by John Clague, Chris Yorath, and Richard Franklin, Tricouni Press, 2006