Earthquakes in the grand scheme of things

“Scientists Fear the BIG ONE is Coming as FOUR Major Earthquakes Strike in 48 Hours” exclaimed The Express in proper tabloid fashion. Japan is rocked by four quakes in two days, each over 6 on the Richter scale. Not a terrible quake, a 6.0 or so, but a rocker and scary enough. There were even a couple deaths. Japan handles temblors like this well. They are used to them. Of course seismologists worry that they might be foreshocks announcing a real monster of a quake, though Japan is used to those too.  Alas, there is nothing unusual at all about earthquake clusters like the four The Express is screaming about, especially in Japan, where four tectonic plates–the vast North American, Eurasian, and Pacific plates, and the smaller Philippine plate–grind against each other with slow violence. The northern half of Japan is mostly part of the North American plate, the Southern half is the Eurasian plate, and the Pacific plate is forcing itself beneath the Eurasian plate (a process called subduction) at a rate of about three and a half inches a year. Sometimes the subduction process gets stuck for a few years and then, after enough pressure builds up, it moves forward with a jolt. Sometimes it’s a little jolt. Sometimes it’s a 6 point jolt. And sometimes it’s a jolt so big everything shakes to pieces and the sea comes roaring back in a tsunami. That’s Japan. We have earthquakes in California as well, of course, but no one is subducting anybody. Rather our plates are slowly grinding past one another, so that the shaking, even at its worse, cannot get to the same level as Japan is prone to. In Alaska, though, where the Pacific plate is being subducted by the North American plate, you can have earthquakes of astonishing violence, like the one that leveled Anchorage in 1964.

The Express story hinted that the quakes in Japan could set off quakes in, say, California. As if somehow earthquakes were all interconnected. And while earthquakes on the same (or on linked) fault lines can be related theoretically, ones thousands of miles away can’t possibly be, because there would not be enough energy released from an initial quake to go through thousands of miles of solid rock from Japan to California. And the fact that there are four major quakes in 48 hours in a general region–say across East Asia–is just chance, as there are hundreds of quakes 6+ every year and sometimes a few of them happen within a couple day stretch.

Remember that earthquakes, in the grand tectonic plate scheme of things, are extremely minor events, just little quivers, nothing. While to us they can be terrifying, devastating, even catastrophic, in geologic terms they are just everyday things. After all, every great mountain range in the world is the result of literally millions of earthquakes. When you think how few large earthquakes you have lived through living in, say, Los Angeles, you get an idea of the time scale in building mountains, and how we can play no role at all in that process whatsoever. Nothing alive can. Mountains rise and erode as if life never existed at all. Because in the grand scheme of things life means next to nothing, really. Life is just a process for making coal or limestone.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s