What the Tsunami Means for US West Coast

Direction — not distance — will be the key factor with the Pacific Ocean tsunami as it hits the West Coast of the United States, an expert told CNBC Friday.

After hitting Japan, the tsunami swept across the Pacific, moving at a stunning 500 miles per hour. The first waves hit Hawaii at about 8 a.m. ET and reached the first parts of the west coast of North America around 11 a.m.

"There is the possibility there will be some effects on the West Coast," Jose Borrero, USC Tsunami Research Center, told CNBC, adding he doesn't expect a "wall of water." He said to expect "very strong surges and currents and water level changes in harbors."

Borrero said the tsunami was moving in a southwestern direction, but said residents need to be prepared for the strongest waves four to five hours after the first one hits. Another positive, he said, is that the waves would reach shore during low tide.

Tsunamis are caused by displacement of a large body of water, resulting from a major physical event, such as an earthquake, volcanic eruption and even the impact of a meteor.

The Hawaiian Islands would not slow the speed or size of of the water, explained Borrero, because the water surrounding them is very deep. Energy is lost when the wave moves into the shallow water and begins interacting with the continental shelf and the coast line.

That causes a "train-wreck effect," he said. "The friction is greatest at the front of the tsunami, which slows, and the rear of it crashes into the front."

  • Slideshow: Scenes From Japan's Earthquake
  • Nevertheless, Japan issued a tsunami warning—the most serious on its scale, such that wave could reach 10 meters high, or about 30 feet. Thus far, the maximum height was put at 23-feet, or 7 meters.

    The tsunami was triggered by a powerful earthquake in Japan, which registered 8.9 on the Richter scale, near the coastal city of Sendai.

    A December 2004 tsunami off the coast of Sumatra devastated the southern Pacific region, but there have been other major ones in that part of the word in the years since. The 2004 tsunami resonated through the world's oceans for days, said Borrero.