(Image Credit: KATU/ABC News)

ABC News' Lawrence Dechant reports:

Oregonians awoke to a huge surprise Tuesday when a 7-foot-tall dock washed ashore, leaving local and state officials wondering whether it's just the beginning of the bulk of tsunami debris set to arrive this year on the West Coast via currents from Japan.

Chris Havel, spokesman for the Oregon Department of Parks and Recreation, said it is too early to tell exactly where the dock originated, but crews identified a metal placard with Japanese writing that was attached to the dock. The March 2011 earthquake-tsunami left at least 15,000 people dead and swept away cars, boats, buildings, homes and maybe at least one errant dock.

"We sent it [the placard] to the Japanese Consulate in Portland and they are working on it," he said. "We have not received the full translation and are waiting for the consulate to respond. Once they have, we can find out where and when it came from."

A Washington-based, Japanese-speaking journalist who saw a photo of the placard said it reads, the "Misawa District Area Fishing Harbor Maintenance Construction" from Nishimura Industries Inc., which is located at the northern tip of the main island of Japan.  The city of Misawa, located in an area called the Aomori Prefecture, suffered some damage from the tsunami, particularly at the U.S. Air Force base, which had electricity shut down.

Havel said the dock arrived at Agate Beach in Newport, Ore., around 3 a.m. local time Tuesday, after the high tide pushed it far into the beach. The 66-foot-long, 19-foot-wide structure is made of concrete and metal and is too large and too heavy to be moved without the use of machinery.

"We haven't had anything this large and heavy wash up on the beach before," Havel said.

If the next high tide fails to pull the dock back out into the Pacific Ocean, the state might have to demolish it, he said.

"We would prefer not to demolish it, because it would interrupt the … public beach," Havel said. "We are talking to salvage experts to give us a thumbs up or down on whether to demolish it or not."

If the dock has to be destroyed, Havel said officials would attach cables to the dock, as well as boats, and pull it across the surf line. He said demolishing the structure would be a challenge without disturbing beach-goers.

"We will know in the next couple of days which method will be workable," Havel said.

The dock is radiation-free but beach-goers are prohibited from climbing on it, Havel said. Viewing and taking photos are permitted.

Photos and status updates are available on the Oregon Parks and Recreation website.

"We had some people from Pennsylvania visit the beach when I first visited the dock, and they said, 'Is this common,'" Havel said. "I told them, 'No, but you arrived at a special time.'"