Wednesday, August 24, 2011

Which Horseman Are You?

Yesterday, as I was obsessively checking the progress of the nearly-stationary hurricane Irene, I started hearing about an earthquake in Virginia.

Virginia?  And it seemed relatively small, yet people were feeling it in New York, in Ohio, all over the Northeast.

I started out the morning hearing about the earthquake in Colorado.  Now, I'm an educated woman, and I know that the earth is made of plates that often shift.  I lived in Charleston for years, and we were conscious of the earthquakes that the city had suffered in the nineteenth century.  I have in-laws in Memphis, and I know about the faultline there--and the nineteenth century earthquake that made church bells ring in Charleston.  I've seen the huge bolts that nineteenth century builders put in their buildings to hold them together during earthquakes.

And of course, I still have last week's ocean outing on the brain:  all those jellyfish.  My poet brain (or is it my filmmaker brain?) wants to put all these images together.

My imagination runs to apocalypse in the best of times, and each day makes me feel like I'm living in a disaster movie without realizing it.

Or maybe we're living in Old Testament times.  One of my grad school friends used to joke that living in California was like living in the Old Testament, with fires and earthquakes and typhoons.

What's next?  Locusts?  What are some of the other Old Testament plagues?  Frogs, I remember that.  And blood raining from the sky.  Yuck.

Well, in an attempt to regain some composure, I reread the Geology chapter in Natalie Angier's The Canon:  A Whirligig Tour of the Beautiful Basics of Science.  It's fascinating to read about the major tectonic plates and the minor ones, about oceanic plates and the ones that affect land.  When's the last time you thought about earth's mantle and earth's crust?

Here's a fascinating tidbit to fuel your imagination:  the mantle is like silly putty, and the crust is very thin:  ". . . accounting for less than one-half of 1 percent of Earth's mass and 1 percent of its volume" (p. 221).  It's also "the coolest part of Earth, and thus is brittle and prone to fracturing" (p. 221).  There's oceanic crusts and continental crusts.

But tectonic plates "aren't simply broken pieces of the earth's crust" (page 223).  They're deeper than that; they extend into the mantle.  Some of them are thick, some brittle, some more plastic and yielding.  And as we know, they move:  "Give a plate 100 million years, and it will have globetrotted 3,000 miles, nearly the distance between New York and London" (page 223).

So, when the earth moves under our feet, it's not necessarily a sign that the end is upon us.  We think of our planet as solid and unyielding, a hard rock in outer space, but it's not. 

2 comments:

Kathleen said...

I knew I could come here for thoughts on the apocalypse, but I also loved your reflection on the earth's mantle, crust, and tectonic plates!

As to the locusts, earlier this year various friends were shoveling cicadas off their lawns and driveways....

Kristin said...

I did hear an NPR piece on locusts and other small swarms of bugs this year.

So, what's next? Frogs? Hmm.