A Seismic Hazards Overview of the Urban Regions of Nevada: Recent Advancements and Research Directions

Nevada is a large western state in theUnited States with a seismic hazard that ranges from moderate to high, depending on location. This article identifies priorities to improve estimates of the seismic hazard in the most urbanized parts of the state, specifically the Reno-Carson City urban area of western Nevada and the Las Vegas urban region of southern Nevada. Collaborative task forces are needed to efficiently realize these priorities. For the Reno-Carson City region in western Nevada, the seismic hazard is high because of strain distributed across several active faults, including normal faults that dip beneath parts of the urban areas. The subsurface geometry and possible connections of these faults remain to be determined. The present large uncertainty in estimates of the slip rates can be reduced by future geological and geodetic studies, including trenching at more than one site per fault and increasing the density of geodetic stations to include multiple stations in the mountain ranges between faults to detect rotations. Adjustments to the ground-motion models for the regional properties of western and southern Nevada could reduce ground-motion uncertainties. Ground-motion simulation research needs an improved 3D velocity model. The seismic hazard in Las Vegas is lower than in Reno. An expanded geodetic network and continued geological studies of the active faults are needed. Uncertainties in the geometry and activity of the Frenchman Mountain and Eglington faults particularly introduce significant uncertainties into the seismic hazard in the Las Vegas basin. The more distant Garlock and Death Valley faults in eastern California impact the hazard in Las Vegas because the Las Vegas basin amplifies long-period ground motion and prolongs its duration, so reliable simulations from these sources are needed.