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It’s not a huge mystery why Los Angeles experiences earthquakes. The city is right along a boundary between two tectonic plates—they shift, we shake. But what about places that aren’t along tectonic plate boundaries? Seismicity on the North American plate occurs as far afield as southern Missouri, where earthquakes between 1811 and 1812 estimated at around magnitude 7.
0 caused the Mississippi River to flow backward for hours. Until now, the source of that seismicity has remained a mystery. While earthquakes along tectonic plate boundaries are caused by motion between the plates, earthquakes away from fault lines are primarily driven by motion beneath the plates, according to a new study.Image credit: USGS
