Small earthquakes in Ohio and Arkansas associated with hydraulic fracturing for natural gas have taken many people by surprise. Gas industry executives say there's no hard evidence that their activities are causing these quakes. But some scientists say it's certainly possible; in fact, people have been causing quakes for years.
In the 1960s, geologists realized that gold mines in South Africa had created small earthquakes. Caverns dug into the earth thousands of feet below the surface collapsed. The "pancake" effect caused quakes — in one case a magnitude-5.2 temblor.
For two decades, the Pentagon has maintained that it could fight two wars at the same time. But as the Obama administration releases its new military strategy Thursday, some question whether the Pentagon will abandon that long-held commitment.
An early draft of the Pentagon's new strategy, The New York Times reported, said the military would only be able to win one war and spoil an adversary's efforts in a second war.