Posted on December 3, 2009 by
Point Reyes, sliding off into the sea
This past October, my lady friend and I were road tripping on the west coast, driving north from San Francisco to Point Reyes on Route 1, amazed at the complete lack of gas stations for an area so near a major metropolis in the most populous state in the nation. We were running on fumes and beginning to worry. Because I like to keep the lady on her toes, I broke with male tradition by pulling a u-turn to ask a couple walking beside the road where we could get some gas.
Which is totally not the point of this story. For those dying to hear the conclusion to that awesome set-up, we safely filled up a few miles down the road, drove out to the Point and took lots of pictures. It occurred to me at the time that the moment we left Route 1 and headed onto the Point Reyes peninsula was the first time in my life I had ever left the North American Plate. By crossing the San Andreas Fault, we were now on the Pacific Plate and sliding northwest toward Alaska, just like Los Angeles and everything else between there and San Francisco. That’s geology, kids.
Which brings me to the actual point. I was just reading John McPhee’s Pulitzer Prize-winning Annals of the Former World, the magnum opus of geology for the layperson. In the Assembling California volume he describes the events surrounding the 1906 San Francisco earthquake and notes that the maximum jump was at the south end of Tomales Bay, where a road was severed, wrenching apart twenty feet. That’s a lot of shaking, and as best I can figure, it was more or less the exact spot where those kind people pointed us in the direction of a filling station.
And I lied about that being the actual point. That was really just more set-up, a way to explain just how I got to wondering how I could bend my fascination with geology into a post for The Greenists. The answer turned out to be one quick Google search away. “Environmental issues with earthquakes” turned up an About.com article as the first hit explaining how the melting of glacial ice as a result of increasing global temperatures could trigger earthquakes, tsunamis and volcanic eruptions.
Here’s how: Geologic rebound. Glacial ice, especially when it’s on a continental scale such as Greenland or Antarctica, is enormously heavy and actually depresses the surface of the planet in a major way. When that weight is removed, which is happening more quickly as the rate at which glaciers and ice sheets melt has been accelerating, the earth below essentially must spring back into place. This rebound is expressed in movements of the earth’s crust (earthquakes) and could also produce an increase in volcanic activity. Both of these tend to kick off tsunamis.
So in a roundabout way, turning up the thermostat just a touch this winter or leaving the refrigerator door open or sitting on a fault line with your car idling while asking for directions could be contributing to future city-leveling temblors. More than 3,000 people died in the 1906 quake. Last year’s earthquake in China’s Sichuan province killed around 70,000. As if we needed one more thing to blame on global warming.