The Moving Earth, Micro to Mega

When Caltech’s Nadia Lapusta creates computer models of earthquakes, she must integrate an astonishing range of data—on scales from thousands of kilometers down to microns and from millennia down to thousandths of a second. That’s because to understand the big and slow, she needs to understand the tiny and fast. “Large-scale earthquake ruptures—even those around 8 on the Richter scale—are ultimately happening in very narrow layers of granulated rock,” she says. In fact, where one side of a fault moves against the other, those layers are powdered so thin that a stack of a thousand grains would equal the thickness of a credit card. And although a fault can go eons between destructive quakes, the first slip that kicks off the shaking can take place in a blink.

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Mars Makes Two

Mars is Earth’s next-door neighbor, yet the Red Planet is utterly alien—frozen, arid, and roiled by massive dust storms. However, this was not always so. Data sent back from Mars, by JPL’s robotic explorers, paint the picture of two planets that once may have been much more similar. Woody Fischer, Caltech professor of geobiology, is helping to decode the history hidden in Mars’ rocky terrain.

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