On the other hand...

In my last posting I was urging people who hadn't read it to read Bill Bryson's A Short History of Nearly Everything. However, I do have to mention some of the bad news the book conveys. It seems especially relevant given last Friday's earthquake and tsunami in Japan. Coming on the heals of the earthquakes in Haiti and Chili last year, as well as the eruptions of two of Indonesia's active volcanoes (Mount Karangetang erupted again a few hours after the earthquake/tsunami in Japan)...well, there's just no question that the earth beneath our feet is in turmoil. And we can't do a damn thing about it.

There are two unsettling scenarios Bryson discusses in his book. The one has to do with the "hot spot" located beneath Yellowstone National Park. That hot spot is what produces all those spouting geysers and bubbling mud cauldrons that so fascinate visitors. Alas, what it basically is is a volcano, waiting to erupt big time. In fact, it's considered a supervolcano, because the magma chamber deep below the surface is huge, about 45 miles across, or pretty much the size of the park. The park, in other words, visited by thousands of people every year, is the caldera of an active volcano.

There are other "superplumes" on earth -- about thirty -- but the one beneath Yellowstone is the only one that does not lie below the sea (a number of volcanically active, and inhabited, islands -- Hawaii, Iceland, the Azores, the Canary Islands -- do sit atop such superplumes). So when it blows, which it has done about every 600,000 years, it affects a huge area of land. And that land now has lots of people living on it, unlike 630,000 years ago, which is yes, the last time it erupted. In other words, Yellowstone is overdue.

Which makes me want to get there for a visit as fast as I can, before it goes. But which also calls into question my insistence that people who live in dangerous places should just get the heck out of there (see Note of Feb. 1, 2009). For it would seem that there is no safe place. Those ranchers out there in Wyoming and Montana, I'm sure they figure they live in a pretty safe place. Brutal winters, but no hurricanes, no drowning sea coast, no earthquakes, no volcanoes.

And even if you live nowhere near Yellowstone National Park, you could be adversely affected by an eruption as far away as eastern Nebraska. That's where the fossilized remains of a whole slew of animals were found in what is now called Ashfall Fossil Beds State Park. They were buried under ten feet of ash, and had died from breathing in air full of ash. The ash fall from the last eruption covered nearly the whole of the United States west of the Mississippi. And there's no telling how long the volcanic winter from such an eruption would last. This is not a pretty picture.

So what are ya gonna do? You realize you have to "Don't worry, be happy," as the old song put it, because there is nothing you can do to prevent Yellowstone from blowing up...or a meteorite from hitting the earth, another unpleasant possibility Bryson investigates in his book. After all, meteorites have been plowing into the earth for millions of years; why shouldn't it happen again? But now the earth is full of people, and the impact of a meteorite the size of the one that hit what is now Manson, Iowa, about 75,000 years ago, would be devastating for a thousand miles in all directions. Bryson's description of "devastating" -- provided to him by geologists -- is pretty darn scary. Which starts me on another train of thought. Maybe we really need to be pumping money into space exploration, so that we can find some places for the human race to spread out, in case this little globe of ours becomes just plumb uninhabitable.

Ka-boom!

I just watched a fascinating and exciting program on NOVA, Mount St. Helen's: Back from the Dead. All about how Nature reasserted herself after the devastating eruption of May, 1980.

Part of the program had to do with the eruption itself, and with the smaller eruptions that took place over the next few years (of which I was unaware -- I don't think the media was paying much attention, since those weren't cataclysmic eruptions). Although I already had a general idea of the mechanics of a volcanic eruption -- magma being pushed up from deep underground by pressure, until the pressure is so great the magma escapes through the surface, becoming lava once it reaches the surface -- it was interesting to learn that what provides the umph to the kind of eruption at Mt. St. Helen's is water in the magma, that has becomes gas as the result of the intense heat. Actually, it seems incredible that there could be water down there in the first place...wouldn't it be too hot, I'm thinking? And where would water be coming from, 62 miles down?

The program didn't go into either question, but the good ol' Internet has informed me that water arrives deep underground when (for example) the Pacific tectonic plate is pushed under the North American plate, taking with it the water that was on top of and in the interior of the layers that are pushed down. As soon as that water hits the high temperatures of the lower depths, it becomes gas, moving up with the magma toward the surface, miles above, and contributing mightily to the ultimate bang when the surface breaks open. You could say the volcano is breaking wind!

The geologist manque in me finds all this fascinating. But what really gets me is the idea that the earth is just going about its business of evolving, just as it always has. Plates moving -- accompanied by earthquakes, tsunamis, volcanic eruptions -- causing land masses to move, inch by inch (looking at a world map you can see so clearly where South America at one time fit into the crook of Africa). These things have always happened, but now human beings are witness to their happening, thanks to the fact that there are now so many of us, living absolutely everywhere, and thanks to instant communication and satellite pictures. And because there are now so many of us, living absolutely everywhere, we are often inconvenienced by these happenings -- witness the devastation caused by the 2004 tsunami in southeast Asia, the recent earthquakes in Haiti and Chili, witness the massive shutdown of air transport with the eruption of the unpro-nounceable volcano in Iceland. But that is not the earth's concern; it is simply following the laws of its nature. As far as the earth is con-cerned we might as well not be here. And we mites (as humanoids are thought of by an alien entity in a Star Trek book I read recently) on its surface just have to run for cover when necessary. (And praying to the gods to keep the volcano from erupting ain't gonna help, either.)

There was again seismic activity at Mount St. Helen's in 2004. No eruption, no lava flow, but what the geologists call "spines" of lava were pushed up through the floor of the crater. This was truly fascinating, since in a very short period of time they were able to see these huge rock formations appear where none had existed before. But the gas that produces an explosive eruption has apparently dissipated. Until the next batch of gas-laden magma makes it slow but sure way to the surface...in 200 years? A thousand?

The earth is a hard taskmaster, but it certainly is interesting.