Tsunami warning as it happened: Threat to US and Canada ebbs away after earthquake sparks panic

Tsunami warning issued on USA's east coast after earthquake off coast of Alaska

Much of the west coast of the US was woken by the threat of a huge tsunami overnight. But the panic soon subsided after all warnings were eventually withdrawn

Alaska and other parts of North America were bracing itself for disaster after a huge 7.9-magnitude earthquake struck at a shallow depth some 160 miles off the state's coast.

While alerts were originally issued across the entire west coast of America and Canada, they have since been withdrawn for all states. That was after people were told to head to high ground and get safe amid fears the tsunami could cause serious damage.

The US Geological Survey said the quake struck 256 km (157 miles) southeast of Chiniak, Alaska at a depth of 10 km at 0931 GMT on Tuesday morning.

Please allow the live blog above to load

Key Points

• Emergency alerts sent to phones across the US, telling people to move to high ground
• Map shows how long potential tsunami would take to reach land
• Tsunami watch and warning cover much of the west coast of the US and Canada

[23 January 2018 10:27 · Andrew Griffin]

The earthquake has been revised down to 7.9, according to the US Geological Survey.

[23 January 2018 10:28 · Andrew Griffin]

Another update from the tsunami centre:

BASED ON ALL AVAILABLE DATA A TSUNAMI MAY HAVE BEEN GENERATED BY THIS EARTHQUAKE THAT COULD BE DESTRUCTIVE ON COASTAL AREAS EVEN

FAR FROM THE EPICENTER. AN INVESTIGATION IS UNDERWAY TO DETERMINE IF THERE IS A TSUNAMI THREAT TO HAWAII. IF TSUNAMI WAVES IMPACT HAWAII THE ESTIMATED EARLIEST ARRIVAL OF

THE FIRST TSUNAMI WAVE IS

            0423 AM HST TUE 23 JAN 2018

[23 January 2018 10:36 · Andrew Griffin]

The tsunami centre website is still breaking, leaving people without information. It runs a special text only version of its website, but that is broken too. It's not clear why that's happening.

[23 January 2018 10:37 · Andrew Griffin]

People are receiving messages through the emergency alerts feature on their phone. They read:

"Tsunami danger on the coast. Go to high ground or move inland. Listen to local news. –NWS"

[23 January 2018 10:38 · Andrew Griffin]

Other advice tells people to "Evacuate inland or to higher ground aboveand beyond designated tsunami hazard zones or move to an upper floor of a multi-story building depending on your situation".

[23 January 2018 10:39 · Andrew Griffin]

People are reporting on social media that the quake was felt hundreds of miles away, in Anchorage.

[23 January 2018 10:42 · Andrew Griffin]

You can find a live map of the threat on the tsunami centre website here. But an important thing to note is that since the website isn't working properly, it sometimes fails to load the layer that's put on top of the map and shows which areas are under threat – if you don't see anything when you open it, that's why. Consult the map below in this live blog if you want a static version of the same map.

[23 January 2018 10:45 · Andrew Griffin]

A 10 metre wave has been reported by a buoy not far from the epicentre of the earthquake.

[23 January 2018 10:46 · Andrew Griffin]

These buoys will be key to tracking the progress of the tsunami. As detailed below, it will take hours for it to actually arrive in populated areas, so these sensors will be key to seeing whether the disturbance is at dangerous levels.

[23 January 2018 11:02 · Andrew Griffin]

The tsunami centre has confirmed that the tsunami watch and warning is in affect as before, and as in the map highlighted earlier in this blog.