Saturday, July 18, 2015

Places with equal chance of devastation as Seattle - Part 2

So why is almost every city in danger of being wiped out at 1 in 500?  That's because everybody and their dog build to living memory, which is about 1 in 100.  Thus New Orleans only builds seawalls for Granpappy's Great Storm.  They wouldn't get any money to build better.

There was this guy who saved a Japanese coastal village by building a 50 foot high seawall.  He inspired everybody and got the money.  That's because he knew the difference between a run-up on a cliff and the height of water on the flats.  Basic physics and momentum.  Nobody else knew their basic physics.

But that never happens anywhere else and the tsunamis he was building against were 'every day' M8's.  He was on the fringe of the M9.  So, with earthquakes, if Granpappy remembers something, you'll build for it.  That's what happened in California.  So they only get wiped out if you have a coast-raising M9, which they claim is impossible.  :)  And only on the deep basins.

Take Toronto, a chance of an M7 or greater at 1 in 500.  The only disaster they ever built for was Hurricane Hazel in 1954, at 1 in 100.  It's all 'La La La' for anything else.  That M7, which is reflected in the recent sediments, would cause a nuclear release at Pickering, wipe out all the bridges, and put out the power for a month.  Tough being in a 70 story condo!  Would kill 500.

Boston and New York.  Thousands dead.

Cat 5 Hurricane hitting Miami.

And so on.


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