A powerful earthquake has struck off Japan's north-eastern coast, shaking buildings in Tokyo and forcing people out of their homes. Japan issued its most serious tsunami warning, saying a wave as high as 20 ft could strike the coast near Miyagi prefecture.The massive 8.8 magnitude quake struck about 382 kilometers northeast of Tokyo.
Tsunami warnings cover area stretching along entire western coast and Canada from the Mexican border to Chignik Bay in Alaska
Northern California expected to be worst hit with waves between six and seven feet
Evacuations are likely
The West Coast of America has been placed under tsunami watch following the devastating 8.9 magnitude earthquake in Japan.
Waves could peak to as much as seven feet along the coast shortly after 8am PST and residents who live on or near the beach are being told to evacuate and move to higher ground.
The central and northern California coast and Oregon are thought to be the worst hit and waves in this area were expected at any time.
The warnings cover an area stretching along the
In the San Francisco Bay Area, an emergency warning system announcement for a tsunami warning was broadcast just after 1am PST.
A lower-level advisory was issued for the Southern California coast south of Point Concepcion, which includes southern San Luis Obispo County and the counties of Ventura, Los Angeles, Orange and San Diego.
Dangerous coastal flooding accompanied by powerful currents is possible and may continue for several hours after arrival of the initial wave.
Officials do not expect waves to cause damage but are telling people to avoid beach areas.
Unusual wave action from the quake is expected to last several hours.
A state emergency spokesman confirmed that parts of northern California will be worst hit with waves between six and seven feet expected at Crescent City.
California Emergency Management Agency spokesman Jordan Scott said: 'It is very possible there may be some evacuations here. The north near the Oregon border is most likely to see big waves.'
The weather service warned: 'Those feeling the earth shake, seeing unusual wave action, or the water level rising or receding may have only a few minutes before the tsunami arrival and should move immediately.
'Homes and small buildings are not designed to withstand tsunami impacts.'
Cindi Preller of the West Coast and Alaska Tsunami Warning Centre told Fox 11 News that the tsunami could cause some unusually high tides but not major inundations.
She said it was possible that officials will ask that beaches be cleared as a precaution and believed that the situation on the California coast might be similar to the aftermath of last year's Chile quake. That quake caused some small waves but caused no major damage.
There is a heavy police presence on beach areas around California, warning people to stay away and get to a safe area. It is not certain whether there will be a full evacuation yet.
A number of helicopters are also hovering over the area.
Social networking sites exploded with messages about the tsunami, with many warning friends and relatives of people who live on the West Coast to call and wake them up to get them to a safe area.
Manny29 wrote: 'Everyone in California is likely sleeping and do not know about the tsunami warnings, wake them up and get them to a safe place.'
SylviaMaria said: 'Please everyone in Cal, stay away from beaches, get to higher ground and wake up your friends.'
Others were simply offering their prayers for those affected, or about to be, by the earthquake and resulting tsunamis.
There were reports that 'extreme surfers' in both Hawaii and California were on standby on the beach to catch the tsunami waves.
Lori Dengler, professor of geology at Humboldt State University, told CNN that the 'series of surges' due to arrive in the next three or so hours have 'the potential to look a little like what happened in 1964 along the West Coast, when there was quite a bit of damage of flooding in Oregon, Washington, Canada and Crescent City'.
She said: 'Coastal emergency managers are very busy working with first responders and public safety people to organize the process and evacuations.
'It's not something that can be done lightly, people can be injured in the course of evacuating if it's not done in a controlled way.
'The fortunate thing for us on the West Coast is we have a lot of time to get this done, because in much of this part of the West Coast, we're dealing with very rural populations, unlike in Japan, where most people are within earshot of sirens.