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21-41. 3D fault structure and implications for seismic hazard


Closing Date: November 1, 2022

This Research Opportunity will be filled depending on the availability of funds. All application materials must be submitted through USAJobs by 11:59 pm, US Eastern Standard Time, on the closing date.

Please communicate with individual Research Advisor(s) on the right to discuss project ideas and answer specific questions about the Research Opportunity.

How to Apply


The magnitudes and distributions of earthquakes are fundamentally controlled by fault geometries, stress conditions, and frictional properties. Assessments of hazard from the suite of earthquakes that may occur within a fault system depend highly on connectivity among the faults and continuity along them. Our current models of fault connectivity are based primarily on surface trace mapping, with down-dip geometries rarely well constrained and detailed 3D configurations almost entirely lacking. Though challenging to image in detail, fault geometry in three dimensions forms the basis upon which to answer a host of questions about earthquake processes and hazards. Recent research refining hypocenters and focal mechanisms of ever-smaller earthquakes has identified new faults, refined the geometry of known faults, illuminated connections between faults, revealed the frictional properties of faults, and enhanced our understanding of the physical phenomena through which faults slip. Nonetheless, gaps exist in our understanding of the way specific regional fault systems behave, even in the most earthquake-prone regions of the U.S. While decades of dedicated consortium science in Southern California have provided data to help image subsurface fault geometries, the plate boundary fault system in Northern California is substantially less well characterized at depth. Knowledge gaps include unmapped seismogenic structures, uncharacterized connectivity between the region’s major faults, and an evolving understanding of how aseismic slip is distributed along several of the major faults.  

We invite research proposals that can address these science questions through innovative, integrated techniques that improve our 3D representation of faults and thereby provide better physical models of the earthquake process. We seek a postdoctoral researcher who will use innovative techniques integrating seismological, structural, and geomorphic information to constrain fault geometries in Northern California with the aim of improving regional fault system models. Improvements in our ability to represent the fault system may be achieved through a variety of methods largely centered around refining hypocenters and focal mechanisms of seismicity and/or developing tools to construct structurally coherent and justifiable fault geometries through integration of these data with geological, geophysical, and geomorphological information. Motivating proposal questions may involve a diverse array of subjects, including rupture propagation, structural geology & tectonic evolution, aseismic slip, fault growth and mechanics, seismic cycle processes, or others.  

The results and approaches developed by this project may be used in earthquake source models, velocity models, earthquake rupture forecasts, models of seismic versus aseismic moment release, and numerical simulations of rupture along frictionally and geometrically realistic faults. We encourage proposals that expand upon and integrate existing USGS research products, including the Bay Area velocity model, comprehensive catalogs of seismicity from regional seismic instrumentation, locally deployed seismic network arrays, and recently updated fault representations for the National Seismic Hazard Model as well as the definitive Quaternary Active Faults of the U.S. database. Mentors from multiple USGS projects are available to advise this postdoctoral research, ranging from earthquake geologists to statistical seismologists and numerical modelers, across multiple USGS Science Centers. 

Interested applicants are strongly encouraged to contact the Research Advisor(s) early in the application process to discuss project ideas. 

Proposed Duty Station(s): Moffett Field, California; Golden, Colorado 

Areas of PhD: Earth sciences, geology, seismology, planetary sciences or related fields (candidates holding a Ph.D. in other disciplines, but with extensive knowledge and skills relevant to the Research Opportunity may be considered). 

Qualifications: Applicants must meet one of the following qualifications: Research Geologist, Research Geophysicist, or Research Geodesist.  

(This type of research is performed by those who have backgrounds for the occupations stated above.  However, other titles may be applicable depending on the applicant's background, education, and research proposal. The final classification of the position will be made by the Human Resources specialist.) 

Human Resources Office Contact:  Audrey Tsujita, 916-278-9395,

Apply Here