Tsunamis are among the most-devastating natural calamities. These earthquake-generated waves can quickly engulf low-lying land and bring widespread destruction and death. They can deposit sand and debris far inland from where they came ashore.
Now, for the first time, a group of scientists working in the Kuril Islands off the east coast of Russia has documented the scope of tsunami-caused erosion and found that a wave can carry away far more sand and dirt than it deposits.
The fortuitous observations resulted because the Kuril Biocomplexity Project had made detailed surveys of some Kuril Island coastlines during the summer of 2006, and then returned for additional work in the summers of 2007 and 2008. That provided a unique opportunity for before-and-after comparisons following a magnitude 8.3 earthquake and accompanying tsunami on Nov. 15, 2006, and an 8.1 quake and resulting tsunami on Jan. 13, 2007.
When the scientists revisited coastlines they had surveyed in 2006, they found that in some places the amount of sand and soil removed by tsunami erosion was nearly 50 times greater than the amount deposited.
"It was so extreme. I was really surprised," said Breanyn MacInnes, a University of Washington doctoral student in Earth and space sciences.
