The winter earthquake of 923 or early 924 CE remains the benchmark event in the Seattle Fault Zone. It lifted shorelines around Puget Sound and gave geologists one of the most decisive records of the fault’s power.
But that shoreline-lifting earthquake is only part of the zone’s history. A recent Geological Society of America Bulletin study led by Stephen J. Angster, a geologist with the U.S. Geological Survey, looks past the most famous Seattle fault earthquake to examine evidence of earthquakes on lesser-known secondary faults.
At Lytle Beach on Bainbridge Island and at Vasa Park near Bellevue, subtle landforms and trench records suggest evidence of smaller ruptures has been preserved in the landscape but not fully recognized…