The most powerful US quake made the Mississippi run backward, and experts say it could happen again

The most powerful US quake made the Mississippi run backward, and experts say it could happen again

A resurfaced explainer on the New Madrid earthquakes is drawing attention online for one startling reason: It recounts how the most powerful earthquake in modern U.S. history briefly made the Mississippi River run backward.  According to Popular Mechanics, seismologist Otto Nuttli later estimated the three main shocks at roughly 7.2, 7.1, and 7.4 on the body-wave magnitude scale. In later work, he suggested even larger surface-wave magnitudes, w…