Video: Japanese dock washes up in US over one year after tsunami "This is tsunami debris, not just from Japan, but from the tsunami itself," Mr Havel said. A radiation check of the dock came up negative, which was to be expected if the dock broke loose before the nuclear power plant accident triggered by the waves, Mr Havel said. The parks department was overseeing efforts to identify and remove the dock. The dock was first spotted floating offshore Monday, and mistaken by several people for a barge. It washed ashore early Tuesday on Agate Beach, a mile north of Newport on the central Oregon Coast. It's made of concrete with a metal pontoon and measures 66 feet long, 19 feet wide and 7 feet high. State police were posted to keep people from climbing on the dock, said Mitch Vance, shellfish programme manager for the Oregon Department of Fish and Wildlife.