In one to three years, scientists say wind and ocean currents will push some of the massive debris onshore.
The floating debris will most likely be carried by currents toward Washington, Oregon and California before turning toward Hawaii and back again to Asia.
Scientists say if some of the debris is radioactive, it would be very low risk.
Only a small portion of that debris will wash ashore, and how fast it gets there and where it lands depends on buoyancy, material and other factors. Fishing vessels or items that poke out of the water and are more likely influenced by wind may show up in a year, while items like lumber pieces, survey stakes and household items may take two to three years, he said.
If the items aren't blown ashore by winds or get caught up in another oceanic drift, they'll continue to drift in the North Pacific loop and complete the circle in about six years, Ebbesmeyer said.
Much of the debris will be plastic, which doesn't completely break down. That raises concerns about marine pollution and the potential harm to marine life. But the amount of tsunami debris, while massive, still pales in comparison to the litter that is dumped into oceans on a regular basis.
The Associated Press contributed to this report.