The islands of La Palma, Tenerife and Gran Canaria have now been rocked by 50 tremors after a “swarm of seismic” movement of low magnitude between 1.5 and 2.7 were measured.This is reminiscent of the earthquake swarms in Yellowstone over the last few months, which prompted a lot of "what if the Yellowstone volcano blows?" speculation. Similar thoughts go here, but the threat is entirely different.
Express.co.uk reported on Tuesday the islands, popular holiday destinations with Britons, had been struck by 40 earthquakes in just 48 hours.
The shape of La Palma hints that a likely scenarios is for the southwest slope of the volcano to slide into the sea. This would create a tsunami that puts the 2011 Japanese tsunami into the "tiny" category. Perhaps millions of cubic feet of rock and dirt sliding into the Atlantic at hundreds of miles per hour. Displacing millions of cubic feet of water.
Over the years, there have been many big budget movies based on the idea that some number of people suddenly find out they had days or hours left to live. The one kids talked about when I was in 8th or 9th grade was "On the Beach", about Australians waiting around after a thermonuclear war, knowing they all would die. Much more recently, "Armageddon" and "Deep Impact" both showed society waiting for Earth to be hit by a recently discovered comet. The reality of a big slide is something like the last two, waiting for the impact tsunami to hit.
Are you in a position where you could get to a couple of hundred feet elevation in a short drive? How about in under 8 hours? You'd have to be ready to hit the road the moment you heard the volcano blew. Every reporting station in the area would be wiped out, but other seismographic stations would report quickly. Like so many other situations, it would be better to leave an hour early than a minute late. We've just seen the problem in Florida during the Irma evacuation. There's really only two highways out of the state. It seems that being on one of Florida's highest elevations might be enough to survive.
Either that, if you have a boat, get in the boat and prepare to be buffeted around by currents and floating debris. From what I recall seeing of the Japanese tsunami in 2011, the "seas" in the sense of waves are not a problem, it's the floating crap and obstacles. Those are NOT trivial, but nothing about this scenario is.