By: J. P. McCalpin
The Quaternary history of the East Cache fault zone was investigated utilizing surficial geologic mapping, backhoe trenching of fault scarps, surveying the Bonneville highstand shoreline, and measuring quantitative geomorphology of the Bear River Range front. Fault scarps displace deposits of the Bonneville lake cycle and younger sediments for 8 kilometers (4.8 mi) along an area east of Logan, Utah. To the north and south, the less youthful appearing range front either shows no clear evidence of late Quaternary faulting, or exhibits only pre-Bonneville-lake-cycle faults in rare exposures.
The purpose of this study was to more carefully document surface-faulting events in late Pleistocene time and to analyze fault behavior in light of current segmentation models. Secondary goals were to compare late Pleistocene fault behavior with longer term Quaternary behavior, and to refine the present estimates for earthquake potential on the East Cache fault zone. Goals were accomplished by four main tasks: (1) surficial geologic mapping along the fault trace, (2) profiling and trenching of fault scarps, (3) deformation analysis of the Bonneville shoreline, and (4) study of the tectonic geomorphology of the Bear River Range front.
Pages: 37 p.
Location: Cache County
Media Type: Paper Publication