Utah Quakes Reveal Surprising Mantle Movements Beneath the Craton

Scientists reviewing a 1979 northern Utah quake (magnitude 3.8) and eight later deep earthquakes have confirmed they originate in the upper mantle, dozens of miles below the crust, near the Wyoming Craton. The findings, published in The Seismic Record, suggest mantle flow around the craton triggers these deep continental earthquakes, a type of seismic activity that operates very differently from crustal quakes and may vary greatly in size over geologic timescales, underscoring how much about deep Earth remains to be learned.