Monday, March 14, 2011

The fascinating science of a terrible event

The ever-expanding catastrophe faced by Japan's people as a result of last week's earthquake (now rated as a 9.0 on the Richter scale), the tsunami that followed, and now the very real possibility of a nuclear disaster is almost too awful to imagine. No, in fact, it is too awful to imagine and, frankly, I am not sad that my imagination is not up to the task.

All the reports about the events that I have seen or heard emphasize that Japan is about as well-prepared for disaster as any country can be. They are well-aware of the seismic neighborhood in which they live, and they expend every possible effort to make people knowledgable about what could happen and to get them ready for the eventuality. Even so, the devastation is terrible and the tasks people face in rebuilding their lives seem almost beyond human capabilities. It breaks the heart and stuns the mind.

And yet, in spite of all that, if one can manage to step back for a moment from the human devastation and simply consider the science of the event, it is fascinating and - yes, I will even use that terribly overused word that I hate so much - awesome. There was a really good article by Kenneth Chang in The New York Times today which explained in easy-to-understand terms just how awesome it was.

As Chang explained, the force of the earthquake actually moved Japan's coastline, making it, in places, as much as 13 feet closer to the United States West Coast. It also changed the balance of the earth, causing a redistribution of the planet's mass that slightly tilted its axis, and has possibly shortened our days by a couple of millionths of a second.

Chang writes:

That part of Asia, to the surprise of many who look at the geological map, sits on the North American tectonic plate, which wraps up and around the Pacific plate and extends a tentacle southward that part of Japan sits atop. The Pacific plate is moving about 3.5 inches a year in a west-northwest direction, and in that collision — what geologists call a subduction zone — the Pacific plate dives under the North American plate.

Most of the time, the two tectonic plates are stuck together, and the North American plate is squeezed, much like a playing card held between the thumb and forefinger.

As the fingers squeeze the card, it buckles upward until the card pops free.

In the same way, the North American plate buckles, and the eastern part of Japan is slowly pushed to the west. But when the earthquake, which occurred offshore, released the tension, the land jumped back to the east.

As it unbuckled, a 250-mile-long coastal section of Japan dropped in altitude by two feet, which allowed the tsunami to travel farther and faster onto land...


Trying to wrap my head around all of this just makes me wish I had spent more time on geology and earth sciences in school. The processes by which this planet constantly shapes and remakes itself are so finely tuned and so intricate and so downright fascinating that one could spend one's life studying them and never completely understand them. Of course, many scientists do spend their lives in that effort. I envy them.

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