Awareness and preparation are the best defense. Geological Survey Program Excavating Old Quarry trench at English Hill. Note two faults visible in the right trench wall just to the right of the crawler-loader. Faults are less than about 10,000 years old. Close view of trench wall showing one of many faults at English Hill.
Fault extends from top center-right to bottom left corner.
Faulting offsets, and therefore is younger than, the Peoria silt. Deposition of Peoria silt ended about 10,000 to 12,500 years ago. Liquefaction caused sand dike cutting through clay and silt deposits exposed in the west bank of Dudley Main Ditch. Note that the sand dike has the characteristic taper of liquefaction dikes, larger near the bottom source area to smaller at the top where it was trying to erupt onto the ground surface. Age of dike is poorly constrained between 22,700 and 3,750 years old.