Test Driving with Geology

I once again hauled myself out of bed at the buttcrack o' dawn and headed down to a dealership for some desultory tire-kicking.  I shall not yet be naming names, but let's just say that prior to this there was a spirited exchange between me and the salesman, in which I discovered he'd started reading ye olde blog.  I've never yet test-driven a car with a reader.

I'll be utterly honest: I liked him, and not just because he said flattering things about this humble cyber-cantina.  He spent time getting a good feel for what I wanted, and aimed me in appropriate directions. This is precisely what dealers should do, and it's appreciated.  Either Seattle's different or things have changed since I last trailed my father around to different dealerships, doing awful things like test-driving cars in snowstorms because my dad knew he'd get a better bargain on yucky days, because I haven't yet run into dealers oozing oil.  My dear dealer-reader stands out even among the comfortable salesmen I've spent the last few days with.  Even if I don't end up buying a car from him, I'll have no problem steering business his way.


His identity shall be revealed at the end of my searches, as long as he consents.  Otherwise, you can contact me for the info, should you be in the Seattle area and wanting to see a man about a car.

Tomorrow, it's off to my stalkers at Nissan for a discussion about the price of new cars and how my bank account can't deal with same.  Look, I have books to buy and field trips to finance - not going to spend all of my monthly cash on a car, m'kay?  Today's dealer seems to understand that.  Will they?

So yes, car shopping continues fine, and I'm now spoiled for choice.  My intrepid companion's agreed to allow me to drag him along tomorrow to help me narrow down the final contenders - since he's always with me on these trips, he should have some input regarding the car I stuff him in to.

I see you squirming.  You're tired of this car-shopping talk and want your geology, don't you?  Well, you shall have it.

You see, my dealer has been perusing some posts here, and we discussed a bit o' this and that whilst tooling around in various autos.  At one point, he asked me if there were volcanoes near Seattle.  Meaning, other than Mounts Rainier and Baker (if you ever get to meet him in person, ask about Baker - you'll marvel).

That would be a huge yes.  There's Glacier Peak, in fact, which was recently highlighted by my favorite Northwest geoblogger, Dan McShane.  Mount Rainier's closer, but not by much, and if you're living in the North Sound sneering at all those idiots in the South Sound who might get buried in the next big eruption, well, between Baker and Glacier Peak, you're probably covered.  In lahars, that is.

Courtesy of USGS

Courtesy of USGS

The biggest danger from Mount Rainier is to the South Sound area, and we're not so much worried about it going boom as going splat:

Courtesy of USGS

Rainier's not very noisy as far as stratovolcanoes go, not likely to put on a big pyrotechnic show, but it's rotting from the inside.  It's one tiny eruption, one heavy warm rainfall, or one earthquake away from releasing a mudflow that will seriously inconvenience a good number of Puget Lowland residents.  It's not considered the most dangerous volcano in America for nothing.


So, neither of the easily-visible volcanoes are likely to present Seattle with an impressive show (unless you count being buried under volcanic mudflows as a great afternoon's entertainment).  But Glacier Peak's been known to go boom in a big way (pdf).

Courtesy of USGS

It's not the most active of our area's volcanoes, but if it wakes up, it could very well get our attention.  And while the winds usually blow east, they don't always.  Seattle could end up buried under ash, and from a mountain people don't always realize is there, or recognize as a volcano.  Glacier Peak hides among the peaks of the Cascades rather than dominating the skyline on its own.  It's easy to overlook, but it sure won't be when it blows.

So, why do we have mountains created by uplift and folding, and mountains created by booms big and small, all looming on Seattle's skyline?  Let's have a look at a couple of illustrations.

First, the Cascade volcanoes:

Courtesy of USGS

Now the Cascade Range as a whole:

Courtesy of Wikipedia

You may notice a distinct linear motif.  There are many hefty geologic tomes, research papers, and seminars that explain just why this is, but we can sum up thusly:

Courtesy of PNSN

Classic subduction zone, my darlings.  As the North American plate heads west, the Juan de Fuca plate goes down under.  So you get mountain-building because things get smooshed- just run a couple of throw rugs in to each other, and you'll see the wrinkles develop.  Now imagine you had a heat source under the floor, and one rug dipping into it as it slides beneath the top rug.  Bits melt.  Warm things being warm, the melty bits rise, and find weak spots to escape from, and you have volcanoes amidst your wrinkly bits.  Crash!  Bang!  Ba-boom!

That's the quick-and-dirty explanation of what's going on round the Seattle area.  It's what gives us spectacular scenery that could very well kill us one day.  And to think I haven't even mentioned the faults, the subduction zone quakes, and the tsunamis!  Or the three thousand feet of ice we'll be enjoying if the Ice Age decides to mount a comeback.

Just look at it this way: we've got a front-row seat to some of the most spectacular shows geology can put on.  As I told my dear dealer, our geology's young, but it's had a busy youth.  And it ain't half done yet.