Experience Earths ferocious power! Vancouver is completely submerged. Seattle and Portland are decimated by volcanoes, landslides and tsunamis. An earthquake might not destroy the west coastbut a megaquake just might. Californians have been ready for The Big One for decades, but a temblor much farther north on the San Andreas Fault may spring to life. And, it could be ten times bigger. Most earthquakes last for a minute, but a megathrust earthquake can last for five powerful enough to trigger a cascade of smaller earthquakes and even reignite extinct volcanoes. Join leading geologists and discover why Americas northwest may be in imminent danger. It just might make you tremble.
The West Coast of America has long been ready for 'The Big One': the moment when the San Andreas Fault springs to life. But what if defences have been pointing in the wrong direction? What if a far bigger earthquake is on its way - one that could submerge Vancouver and destroy Seattle and Portland by unleashing a string of re-ignited volcanoes, landslides and tsunamis? Welcome to the world of the 'megathrust' quake - ten times bigger than anything San Andreas can deliver. Have the beginnings of a tremor already begun?. The skyscrapers of San Francisco and Los Angeles have been built to withstand earthquakes of up to 7 on the Richter scale. Homes have been reinforced. Everyone is confident that when the Big One strikes, we will be ready.
But what if our defences have been pointing in the wrong direction? What if a far bigger earthquake could strike the West Coast of America one that could submerge Vancouver, and destroy Seattle and Portland by unleashing a string of volcanoes, landslides and tsunamis? This megathrust quake an earthquake 10 times bigger than anything the San Andreas Fault can deliver could, it seems, happen at any time.
The story starts with geologist Thomas Heaton, who was sent out to look at the site for a proposed nuclear power station in Washington State. It should have been a routine job; all the geological maps said this area was as geologically stable as anywhere on the planet. But then Heaton discovered evidence of a giant earthquake in the recent past. What could have caused it?
The only serious geological feature in the area was the Cascadia subduction zone, a huge underwater area where the Oceanic Pacific plate slides under the continental plate of the US. This particular subduction zones was thought to be a geological pussycat interesting enough if you were an earth scientist, but not remotely dangerous. So Heaton wondered could it have caused the earthquake and if so, how?
Most geologists rubbished the idea there was no proof of any such huge earthquakes in the past. But Brian Atwater, of the US Geological Survey, decided to investigate. Slowly, Atwater uncovered a trail of clues a sunken forest, evidence of a tsunami in Japan from the 18th century, fabulous tales of the anger of the Gods from Native American legends. Eventually he discovered that not only had there been an earthquake of a colossal 9 on the Richter scale, but he could pinpoint its precise date: January 27th 1700. Now it was not a question of whether or not it had struck, but when it would strike again.
Last year, Mladen Nedimovic of the Lamont Doherty Earth Observatory discovered that the Cascadia subduction zone is now locked across a huge area in other words poised to strike. Others have found that silent quakes minor tremors have begun. Everything indicates that the megaquake is coming. When it does, the research suggests it will be unlike anything we have ever seen. Most earthquakes last for a minute. A megathrust earthquake can last for five. It could be powerful enough to reawaken long dormant faults, sending a cascade of smaller earthquakes down the north west of America, and reigniting extinct volcanoes. There is even a suggestion that giant landslides could be triggered on Mt Rainier, destroying Seattle.. Disc 1: The Next Megaquake and Earthquake Storms (bonus)