Earthquake!

[Tigger]

4.9, 22 km north of Victoria and 40+ km deep. We felt it, but the shaking only lasted for a second. Ish? Kim? Anyone else?

[JoeP]

Didn't feel it in Tacoma.

[kimbottles]

We did not shake in Blakely Harbor......but we are at least 50 miles south of you Jim.

[Panope]

Nothing in Port Townsend. Then again, I sleep like I am dead. Probably take at least a 5 or 6 to wake me up.

Steve

[Ish]

Yes, we felt it, not too much rattle. Epicenter was placed in Hughes Passage, between Sidney and D'Arcy Islands, but I don't know how deep.

CBC had an interesting video clip on it. http://www.cbc.ca/news/canada/british-columbia/earthquake-bc-south-coast-1.3384066

[SloopJonB]

It was deep - report I saw said 40 kilometers down.

I guess now we'll get a couple of weeks worth of reports about "The Big One" yet again.

[Ish]

It was deep - report I saw said 40 kilometers down.

I guess now we'll get a couple of weeks worth of reports about "The Big One" yet again.

We were deluged by phone calls from all over the place (it must be a slow news week) demanding to know if we were OK. Well, yes we were, until your phone call woke us up, thankyouverymuch.

There will be the usual firestorm of opinion and caterwauling and all the local businesses will traipse out the "earthquake kits" that didn't sell after the last seven scares. Somehow, I don't think 25' of polypropylene, an 8X10 tarp, a 5-gallon pail, a crappy LED flashlight and a box of soggy matches will do much good in the event we do get a big one.

We have a major earthquake kit that is regularly replenished and I hope we never have to use it.

[Tigger]

If it all truly goes to hell in a handbasket--and it could--I figure that as long as there is not a tsunami in the Salish Sea, and I'm not dead or injured ... I'll be on the boat.

[BeauV]

If it all truly goes to hell in a handbasket--and it could--I figure that as long as there is not a tsunami in the Salish Sea, and I'm not dead or injured ... I'll be on the boat.

Boats are good that way. If they can be kept on a mooring in deepwater, even better. That said, watching the 10-15 knot currents rip the docks apart and sing two dozen boats in Santa Cruz Harbor after the last "big one" in Japan - I think there are a LOT better places to have a boat than our little harbor when there's a tsunami! MAYAN is pretty well stocked - about two weeks worth of food/water.

On a related note: When I was a boy, and the Cuban missile crisis was going on, my Dad loaded our boat up with stores and got her ready to go. He figured that if N. War came we'd just start sailing out to sea on a tight reach and that most of the fall-out would be behind us. Just as the plot lays out in "On The Beach" (a movie from 1959) we'd have to get to the southern hemisphere quickly, before the fall out could spin round the Pacific on the trade winds. It was the first time I really understood what the trade winds did - that when we bombed Russia, within weeks we'd be sitting under our own fall out as the NW trades brought it around the globe.

I'm sure glad we never needed those supplies.

[SloopJonB]

If it all truly goes to hell in a handbasket--and it could--I figure that as long as there is not a tsunami in the Salish Sea, and I'm not dead or injured ... I'll be on the boat.

I wouldn't want to be on the west coast or on the shore of Juan De Fuca but I seriously doubt a tsunami could make it through all the islands, turn the corner and make it to Vancouver in damaging form.

[Ish]

Here's a tsunami model that Paul (VALIS) found. http://www.pac.dfo-mpo.gc.ca/science/oceans/tsunamis/medium-tsunami-moyenne-eng.htm

[Ish]

And just for fun, here's the Puget Sound inundation chart that someone on SA found. http://file.dnr.wa.gov/publications/ger_tsunami_inundation_maps.pdf

[BeauV]

Ish,

Those charts are REALLY interesting. They confirm exactly what I observed in Santa Cruz. I have used a dark-humor approach in describing it as a fat guy sliding down in the tub. There is a massive "slosh" up the end of each inlet, just like when the fat guy slips rapidly down into the tub.

Let me say that the one Really Big Thing I learned from this tsunami is to do what the old timers did - get the hell out of the harbor. They anchored in 100' of water off shore and had a calm, but worrisome day as they watch the masts crashing and listened to the chatter on radio and phone about the destruction of their harbor.

In Santa Cruz we saw a 6 foot peak-to-trough tsunami wave height at the harbor entrance, clearly the wave was feeling bottom as out at the Mile Buoy (apx 1 mile off shore) in 70' of water they only observed about a 1.5 to 2.0 wave with their depth finders. The 6 foot wave started moving up into the harbor (see chart below) and as the flow narrowed the wave height quite naturally increased and the water velocity went way WAY up. Bernoulli's Principal at work, I think. By the time the wave hit the top (north end) of the Harbor the wave was clearly 10 to 12 feet high.

A note on the "wave". It doesn't look like a wave when it's coming in. I just looks like the tide but on a grand a massively faster scale. At the bridge in the middle of the chart below the water dropped to at least a -7 Below MLW (the bridge has a scale mounted on it and -7 is as low as it goes, the water level was about 3-4 feet below that. This resulted in well over 1/2 the Harbor having no water in it at all.

The destruction was caused by the relatively high frequency of the wave(s). There were at least 10 "waves" of significant height in the tsunami, and the first one wasn't the largest, the 4th or 5th one was; another mis-conception I had about the "wave". The frequency was about 1 peak every 10 to 15 minutes.

What this resulted in was the Harbor draining by about 70% (of the volume) over the course of about 3-4 minutes, a pause of about a minute, then the Harbor re-filled in about 1-2 minutes! That means that the current flowing in through the harbor was between 10 and 15 knots at times near the narrow bits. When it struck boats beam on it heeled the powerboats over a bit, but it grabbed the keels of sailboats and simply flipped them on their sides. This was quite dramatic as the rigs crashed down on adjacent boats, dismasting the flipped boat, and if the flow of water managed to catch the lip of the hull/deck joint it would roll the boat all the way over. The boats that were sunk we typically beam to the current flow or were pinned to something (like the bridge) and driven underwater by the flow rate.

Photo Gallery (including many from yours truly) of the tsunami is here: http://www.santacruzharbor.org/tsunamiphotoGallery.html Photo #4 illustrates the roll-over that the current caused for sailboats caught abeam to the flow.

In the map below, North is to the right. Japan, obviously is off to the top of the drawing, but the water came around the 90° corner and into the harbor without any trouble at all. This is, obviously, because it's not a "wave" as we normally think of one, but is simply a very VERY large incoming tide where the water level rises by many many feet and then falls again about once every 10-15 minutes.

[Bull City]

I've been reading Simon Winchester's book about the explosion of Krakatoa in 1883. The tsunamis were responsible for most of the 36,000 (perhaps many more) deaths. The book is excellent.

One thing I have learned is that if you at the coast and the water inexplicably drops in a substantial way, run for the hills.

BTW, we didn't feel any tremors yesterday.

[BeauV]

There is an island in the Ægean called "Satorini" which used to be called "Thera" in ancient times. It blew up around 1,000 BC - if memory serves.

The high water mark in some of the inlets on the mainland of Greece is about 350 feet above sea level. That's a BIG slosh and probably killed a LOT of folks. Again working from memory, the Thera explosion was substantially larger than Krakatoa.

https://en.wikipedia.org/wiki/Minoan_eruption


What's left of Thera:

[SloopJonB]

Read up on Lituya Bay in Alaska in 1958. A landslide induced localized tsunami - over 1700' high as I recall. People in boats at the mouth of the bay actually rode it out to sea and survived - they surfed right over the island at the mouth of the bay.

[Bull City]

The book I mentioned, Krakatoa: the day the world exploded by Simon Winchester, is full of delicious little factoids, such as this footnote about William Syer Bristowe, the English arachnologist who surveyed the spider species on a neighboring island in 1930:

“Bristowe is perhaps the most famous figure in the spider world, known for calculating that the weight of insects devoured by British spiders in an average year exceeds the total weight of all British people combined.”

Something to think about.

[BeauV]

I just stumbled over a video of the Tsunami in Japan that I hadn't seen. Check out the size of the tsunami wall built around this harbor, it must be 30' high. Then watch what the water does to it! It's 9+ minutes, so you may want to fast forward.

[youtube]http://www.youtube.com/watch?v=GOpiL64kRbY[/youtube]