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.
The earthquake rate in the central United States increased more than tenfold in the decade after 2008. The rate change is not a natural phenomenon but can, instead, be explained as a dramatic increase in the number of earthquakes induced by fluid-injection activities like wastewater disposal and hydraulic fracturing. Multiple magnitude 5+ earthquakes have occurred during this surge in seismicity including, in Oklahoma, the 2016 M5.8 Pawnee earthquake and the M5.0 Cushing earthquake that occurred near the largest oil storage facility in the country, and in 2020 the M5.0 West Texas earthquake.
While the dramatic increase in injection-induced seismicity is primarily coming from oil and gas related wastewater disposal, the use of clean energy processes that have the potential to induce earthquakes (geothermal energy production and geological carbon sequestration) has been increasing significantly over the past few years.
Numerous studies of injection induced earthquakes have been carried out over the past 10 years, but there are still an extraordinary number of unanswered questions. Of particular interest is understanding what the operational and geological controls are in determining whether earthquakes are likely to be induced by injection activities of any kind.
We seek a Mendenhall Postdoctoral Scholar to investigate induced seismicity through detailed analyses of geophysical data in regions of active injection with the broad goal of understanding the physical processes underpinning and controlling injection-induced seismicity.
The candidate could explore a wide range of topics, including but not limited to:
- Spatiotemporal analysis: Induced earthquake sequences can reveal details about preexisting fault structures and the evolution of stresses due to changes fluid pressures and poroelastic stresses.
- Source properties: Induced earthquakes are responding to rapid changes in stress and are often occurring on faults that have not slipped in hundreds of years or more. Given that these conditions are different than for most natural earthquakes, analysis of source properties may reveal variations in the source physics of induced earthquakes.
- Temporal evolution of subsurface properties: Subsurface injection of fluids undoubtedly changes the conditions at depth both through increased fluid pressures and the poroelastic response of the host rock. Changes in these properties would provide clues into where and when fluids are moving, material properties of the host rock, preferential flow directions, and could possibly give insight into the absolute stress conditions at depth.
- Physics-based seismicity forecasts: Recent work has shown physics-based forecasting of induced seismicity hazard, where seismicity rates are simulated from injection rates, may be more accurate than purely statistical approaches. However, there are outstanding questions regarding appropriate modeling choices and methodologies that warrant further study.
- Numerical modeling: Numerical modeling of the seismic response to injection can yield valuable insights into determining which operational and geologic parameters influence whether injection wells are likely to induce earthquakes; the physics underpinning induced and natural seismicity; and providing enhanced input into the National Seismic Hazard Model for induced seismicity.
- Geodesy: Subsurface injection and extraction of fluids has been seen to cause measurable ground deformation. Observation of this deformation, or the lack thereof, gives clues into how the subsurface is responding to the changes in fluid in the system. Developing methods to forecast ground deformation due to injection would be valuable in understanding induced seismicity and particularly useful for including in hazard forecasts. Geodetic data can also be used to image the rupture of induced earthquakes, which reveal a connection between their rupture behavior and injection operational patterns.
- Geomechanics: Induced seismicity is fundamentally a geomechanical problem. A deeper understanding of the state of stress and how materials at depth are responding to the changes in stress conditions caused by injection can be used to inform larger scale models of induced seismicity. With additional instrumentation for in-situ measurements of strain and pore pressure coming online, there are many opportunities to carefully characterize this behavior. Geomechanics can also be used to forecast reservoir integrity in response to strong shaking – a key issue for carbon sequestration.
Proposed Duty Station: Moffett Field, California; Pasadena, California; Vancouver, Washington
Areas of Ph.D.: Geophysics, seismology, geodesy, geomechanics, or related fields (candidates holding a Ph.D. in other disciplines but with knowledge and skills relevant to the Research Opportunity may be considered).
Qualifications: Applicants must meet one the following qualification: Research Geophysicist.
(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 USGS Human Resources specialist.)
Human Resources Office Contact: Audrey Tsujita, 916-278-9395, email@example.com