Clue Three: The Japanese connection
Carbon dating showed that the Washington and Oregon ghost forests
had died between the years 1680 and 1720. Atwater reasoned that
a massive earthquake in the Northwest could have killed the ghost
trees. He also knew that such a large quake would generate tsunamis.
These waves would strike all around the Pacific. So he looked to
Japan for evidence, because Japan has some of the oldest written
records of any country along the Pacific Rim.
Japanese researchers found records of only one large tsunami between
1680 and 1720. From maps and manuscripts, they learned that the
tsunami had flooded several Japanese villages, including one called
Otsuchi. If a Northwest earthquake had caused this tsunami, they
calculated, the event would have taken place on the evening of January
The town of Otsuchi, Japan, was damaged by a tsunami in 1700.
|Otsuchi manuscript. In part, this manuscript states
that the coastal village of Otsuchi was inundated by a very
high tide up to the houses behind the street. Rice paddies,
vegetable fields, and salt-evaporation kilns were damaged.
Clue Four: Tree ring evidence
Tree rings provided the last clue. Trees add rings of new wood
each year. Good seasons produce wide rings, poor seasons produce
narrow ones, or none. With this knowledge, scientists who study
tree rings can date past events. Researcher David Yamaguchi found
that the ghost forest trees were alive and healthy in late 1699,
but dead by spring of 1700.
|A trees growth rings (sets
of light and dark lines) tell its age and something about the
environment in which it lived. Dots show decades.
Clues add up BIG
From all these clues, researchers concluded that a huge earthquake
had occurred 300 years ago along the entire Washington and Oregon
coast. This Big One was a major subduction zone earthquake. A similar-sized
quake could occur again at any time....