The magnitude 5.4 earthquake that jolted Southern California late Tuesday morning appears to have been generated by the “Yorba Linda trend,” a little-known seismic zone that extends from northeast Yorba Linda through the Chino Hills and into the Chino basin, says Caltech seismologist Egill Hauksson. (Click map to enlarge. Image shows approximate location of fault zone.)
Scientists originally said the quake, which occurred at 11:42 a.m. Tuesday, was “consistent with motion on the Whittier fault.” But further review reveals that the quake actually was produced by the Yorba Linda trend, a 1 to 2 mile wide fault system that cuts through the area where the Whittier, Elsinore and Chino Hills faults meet in and around the northern end of the Santa Ana Mountains. Hauksson — whose wife is famed seismologist Lucy Jones — discovered the Yorba Linda trend and first identified it in scientific papers in the late 1990s.
“There are a lot of small seismic zones that really don’t belong to the big systems like the Whittier fault; they sort of form a halo around them,” Hauksson says. “That’s what we have here.”
While the Yorba Linda trend isn’t huge, it is potentially deadly. Hauksson estimated that the fault could produce a magnitude 6.0 quake, which is large enough to cause destruction in parts of Orange, Riverside and Los Angeles counties.
pretty neat