. >> the idea is that a tsunam i comes from another place, and you don't know where >>> brian atwater is a geologist. >> in the aftermath of the disaster, japanese experts said what other ones do we have in our history that came from peru or chili >>> when the reckoning was finished there was one tsunam i with no match, one in january 1700. searching for the earthquake which caused that or fan tsunam i researchers looked to the pacific north-west. >> this is probably the most distinct >>> there they found irrefutable geological proof in a cross-section of marsh land. >> the soil of an marsh down here, then sand mutt layers like that-- mud layers like that. each of these are interpreted as a wave in the train of the evening of 26 january 1700 by the japanese dating >>> there's one more clue from the 1700 earthquake and tsunam i. a piece of evidence pointing to the zones ability to produce what geologists call a giant earth quake, registering a magnitude 9 or higher. high school science teacher john harwood took us out onto the elk wood river. itch >> i see a tree and another one here >