Scientists Scramble to Map Previously Unknown Fault That Caused Napa Quake

Sunday’s 6.0 magnitude earthquake in Napa, California, was a jolt from the blue, involving previously unknown active fault lines as well as faults that were thought to be inactive. The quake caused widespread damage that may total several billion dollars, and scientists say it revealed new movement in 1.6 million-year-old faults. Ruptures on the surface, including sections of pavement that buckled, to the delight of area skateboarders, are now helping scientists map these fault lines, shedding insight into the area’s earthquake risk exposure.