This geologic map was produced to compile and reinterpret published geologic information, and present the result of new geologic mapping in the Ray-Superior area. This data set serves as the basis for ongoing efforts to better understand the geologic history of this area, particularly with respect to the distribution and origin of mineral deposits.
Have earthquakes strong enough to rupture the ground surface occurred on faults in central Arizona during the recent geologic past? Could such earthquakes happen in the future? If so, where are they most likely to occur? The Seismotectonics and Geophysics Section of the U.S. Bureau of Reclamation has, during the last 6 years, been working on answering these questions
Horseshoe and Bartlett Dams are located In the Transition Zone of central Arizona. Within this province, faults with evidence of Quaternary activity are widely scattered, and selsmiclty Is low In comparison to other parts of the western United States. However, most of the known or suspected Quaternary faults and most of the historic selsmlclty In Arizona occur within or adjacent to the Transition Zone.
This report presents an assessment of the seismic hazard associated with the Sugarloaf fault, which crosses State Route (SR) 87 near Mesquite Wash in central Arizona. The Sugarloaf fault is a 20 km (12 mile) long, northwest- to north-trending normal fault with displacement down to the east. We conducted a multi-faceted investigation in order to evaluate the late Quaternary behavior of the Sugarloaf fault and assess the seismic hazard associated with it.
This report presents the results of a reconnaissance analysis of Quaternary faulting in central Arizona, conducted for the U.S. Bureau of Reclamation. The goal of this study has been to thoroughly delineate locations of possible Quaternary faulting in the area surrounding existing and potential dam sites in central Arizona.
Probable quaternary faults in Arizona have been mapped by systematic interpretation of aerial photographs, extensive geomorphic field studies, and compilation of previous work. Greatest concentrations of late Quaternary normal faults are found near the Colorado Plateau margin in northwestern and north-central Arizona, with lesser concentrations in central and southeastern Arizona and the Lake Mead area. Late Quaternary faults are rare in southwestern Arizona and none have been recognized in the interior of the Colorado Plateau province in northeastern Arizona.