Tsunami alerts were issued for the entire west coast of North America after a huge 7.9-magnitude earthquake struck around 160 miles off the cost of Alaska.

Despite fears coasts as far south as California could be struck by tidal waves, many warnings were soon called off. A tsunami advisory - issued when there is the potential for dangerously strong currents or waves - was still in effect in south Alaska and the Alaska Peninsula.

The US Geological Survey said the quake struck at a depth of 10km at 12.21am local time on Tuesday morning.

The US National Weather Service had initially issued a tsunami warning for the coasts of Alaska and British Columbia, Canada.

Citizens were advised to immediately get away from coastal areas and up to higher ground at least 100ft above sea level, with any wave expected within the first couple of hours of the quake.

The west coast of the US was on tsunami watch. According to the US National Tsunami Warning Center (NTWC), any potential wave could have struck the coasts of Washington state, Oregon and California within the first six hours of the earthquake.

The NTWC warned tsunami waves could “impact Hawaii”, though this was later cancelled.

Any tsunami was expected to hit the small fishing town of Kodiak, Alaska, first. Kodiak has an estimated population of just above 6,000 people.

The National Weather Service said that a buoy just north-west of the epicentre recorded a displacement of 10 metres.

The Anchorage Office of Emergency Management said in a warning for people in Alaska and British Columbia, Canada: "If you are located in this coastal area, move inland to higher ground. Tsunami warnings mean that a tsunami with significant inundation is possible or is already occurring."