U seismologists are learning what continental mantle earthquakes, occurring far below Earth's crust, reveal about what lies beneath northeast Utah and southwest Wyoming.
U seismologists are learning what continental mantle earthquakes, occurring far below Earth's crust, reveal about what lies beneath northeast Utah and southwest Wyoming.
Nearly 50 years ago, a puzzling earthquake beneath northern Utah jolted scientists’ understanding of how Earth works. Now, research from the University of Utah confirms that the mysterious event was real, and part of a rare class of earthquakes occurring far deeper beneath the continental crust than scientists once believed possible.
In the early morning hours of Feb. 24, 1979, the University of Utah Seismograph Stations recorded the quake under Randolph, a Utah town near the Idaho and Wyoming borders. No one reported feeling the quake, despite its magnitude 3.8 heft, and the accompanying seismic data didn’t make sense.
George Zandt, then a postdoctoral seismology researcher at the U, took a closer look at the seismic readings and pinpointed this quake’s focal depth at a jaw-dropping 90 kilometers below sea level. Such a depth was not thought possible, placing its hypocenter far below Earth’s crust, well into the upper mantle.
Read More: University of Utah
