Next-generation crustal stress mapping: Seismic hazards, active tectonics, and resource development
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Jens-Erik Lund Snee (Lundstern)
USGS
- Date & Time
- Location
- Online-only seminar via Microsoft Teams
- Host
- Lisa Schleicher
- Summary
The stress field determines patterns of deformation in the Earth’s crust, including the subset of faults that are seismically active and permeable to fluids. In the decades since the first regional stress maps were developed in the 1950s, enormous strides have been made in measuring and mapping maximum horizontal stress (SHmax) orientations worldwide. Recently, I published a next-generation stress map for North America, which includes the continent’s first quantitative depiction of relative stress magnitudes (faulting regime) as well as a more detailed picture of SHmax orientations. These new datasets show that stress can vary over a wide range of spatial scales, contrary to earlier suggestions that continents are characterized by provinces of consistent principal stress orientations separated by narrow transition zones. The stress field is especially variable in the more extensional (normal, normal/strike-slip, and strike-slip faulting) environments observed over most of the western U.S., where several marked rotations of SHmax occur over tens to hundreds of kilometers, which raises unresolved questions about the sources of intraplate stress variability. In this talk, I present these datasets and the methods used to develop them, and I discuss their utility for characterizing earthquake hazards (both natural and induced), understanding the drivers of active tectonics, and improving development of oil, gas, and geothermal resources. I focus especially on ways that stress data can be used to identify potential earthquake hazards during subsurface industrial operations, especially when paired with geologic characterization and operational data. Finally, I discuss ways that detailed stress datasets might contribute to addressing outstanding research questions on crustal strength, plate boundary coupling, and the earthquake cycle.