The Intermountain West contains some of the fastest growing urban centers in the United States, and several are exposed to a substantial level of seismic hazard. It is critical to accurately quantify this hazard, and ultimately, the associated risk.
We conduct geologic, geophysical, and paleoseismic studies of selected faults that have a high impact on urban centers and whose rupture histories will significantly influence future generations of the hazard maps. These studies will refine our understanding of prehistoric earthquake chronologies, the segmentation of faults, and the spatial distribution of prehistoric ruptures. Collectively, this information will yield a better understanding of the hazard and better define time-dependent probabilities of large earthquakes. Field studies of hazardous faults provide critical information about the fault slip rates, magnitude estimates of paleoearthquakes, the time since the last surface-rupturing earthquake, recurrence intervals, and the distribution of ruptures in space and time. This detailed knowledge of a fault's behavior is critical to improved seismic hazard assessments.
We study faults outside of IMW urban centers to better understand how complex faults evolve and rupture. We identify well-preserved late Holocene and historical ruptures that can serve as analogs for hazardous faults in high-risk urbanized regions. Our efforts are focused on methods to improve the accuracy and reproducibility of paleoseismic fault-trench research, and investigations into relations among fault structural complexity, rupture length, surface displacement, and magnitude.
Specific sites for targeted research include:
- Great Salt Lake and Wasatch Front, Utah
- Sawtooth fault, Idaho
- Gore Range and neighboring faults, and Sangre de Cristo fault system, Colorado
- Rio Grande Rift, New Mexico
- Garlock fault system, southern Death Valley faults, Landers area, California
- Bitterroot fault, Montana
- Epicentral region of the 2020 M6.5 Monte Cristo Range earthquake, Nevada
- Chelan Lake, Washington
- Overview
The Intermountain West contains some of the fastest growing urban centers in the United States, and several are exposed to a substantial level of seismic hazard. It is critical to accurately quantify this hazard, and ultimately, the associated risk.
Sources/Usage: Public Domain.Alex Hatem observes surface deformation from the 2020 Monte Cristo, Nevada, earthquake eroding away, June, 2022. We conduct geologic, geophysical, and paleoseismic studies of selected faults that have a high impact on urban centers and whose rupture histories will significantly influence future generations of the hazard maps. These studies will refine our understanding of prehistoric earthquake chronologies, the segmentation of faults, and the spatial distribution of prehistoric ruptures. Collectively, this information will yield a better understanding of the hazard and better define time-dependent probabilities of large earthquakes. Field studies of hazardous faults provide critical information about the fault slip rates, magnitude estimates of paleoearthquakes, the time since the last surface-rupturing earthquake, recurrence intervals, and the distribution of ruptures in space and time. This detailed knowledge of a fault's behavior is critical to improved seismic hazard assessments.
We study faults outside of IMW urban centers to better understand how complex faults evolve and rupture. We identify well-preserved late Holocene and historical ruptures that can serve as analogs for hazardous faults in high-risk urbanized regions. Our efforts are focused on methods to improve the accuracy and reproducibility of paleoseismic fault-trench research, and investigations into relations among fault structural complexity, rupture length, surface displacement, and magnitude.
Sources/Usage: Public Domain.Alex Hatem, Jessie Jobe and Nadine Reitman make observations in a trench across Idaho’s Sawtooth fault, September, 2022. Specific sites for targeted research include:
- Great Salt Lake and Wasatch Front, Utah
- Sawtooth fault, Idaho
- Gore Range and neighboring faults, and Sangre de Cristo fault system, Colorado
- Rio Grande Rift, New Mexico
- Garlock fault system, southern Death Valley faults, Landers area, California
- Bitterroot fault, Montana
- Epicentral region of the 2020 M6.5 Monte Cristo Range earthquake, Nevada
- Chelan Lake, Washington
Sources/Usage: Public Domain.Alex Hatem oversees trench excavation across the Sawtooth fault near Stanley Idaho, September, 2022.
Sources/Usage: Public Domain.Nadine Reitman walks with a camera on a 20-foot pole to generate high resolution DEM’s of the Death Valley fault, May, 2021.
Sources/Usage: Public Domain.Rich Briggs and Alex Hatem make geologic observations within Nevada’s Monte Cristo Range, June, 2022.
Sources/Usage: Public Domain.USGS summer intern, Sierra Rack points to the Gore Range fault during fieldwork near Frisco, Colorado, August, 2022.
Sources/Usage: Public Domain.USGS summer intern, Sierra Rack with Rich Briggs, Alex Hatem and Camille Collett enjoy views and geology near Mt. Sherman after a day of fieldwork in the Gore Range, Colorado.