MAN MADE EARTHQUAKES
In the first Superman movie, supervillain Lex Luthor plans to trigger a massive, California-detaching earthquake by detonating a couple of nuclear weapons in the San Andreas Fault.
Crazy Lex! That scheme never would have worked, geologists will tell you. But, if he’d been serious about creating an earthquake, there are ways he could have actually done it. He would just have to inject some liquid (as some carbon-sequestration schemes propose) deep into the Earth’s crust, or bore a few hundred thousand tons of coal out of a mountain.
It turns out, actually, that the human production of earthquakes is hardly supervillain-worthy. It’s downright commonplace: Klose estimates that 25 percent of Britain’s recorded seismic events were caused by people.
Most of these human-caused quakes are tiny, registering less than four on geologist’s seismic scales. These window-rattlers don’t occur along natural faults, and wouldn’t have happened without human activity — like mining tons of coal or potash. They occur when a mine’s roof collapses, for example, as in the Crandall Canyon collapse in Utah that killed a half-dozen miners last year.
But some human actions can trigger much larger quakes along natural fault lines. That’s because humans, with the aid of our massive machines, can sling enough mass around to shift the pattern of stresses in the
Earth’s crust. Faults that might not have caused an earthquake for a million years can suddenly be pushed to failure, as Klose argues occurred during Australia’s only fatal earthquake in 1989.
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