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.
In the last decade, significant advancements have been made in using fiber optics (FO) for high-resolution seismological applications. With these data, recent research has shown it is possible to observe fundamental aspects of wave propagation and site response, and image shallow subsurface structures in both terrestrial and marine environments.
Array seismology has a long history of being used to improve earthquake location estimates at regional distances in areas that are not easily instrumented with standard networks. Array processing is an attractive tool in working with earthquake datasets with high spatial density, as it offers a robust method for determining slowness and back azimuth from arriving waves, which can help identify seismic phases and the location of the earthquake source. This raises the possibility that fiber optic systems might be useful in supplementing the ShakeAlert™ earthquake early warning (EEW) system, especially in regions that are poorly instrumented and thus prone to detection or location errors – such as the offshore portion of the Cascadia subduction zone, for example. It is also possible that more traditional seismic arrays will become a part of ShakeAlert in the future and require new methods to optimize their use in EEW.
Even with the great potential for FO datasets to complement an EEW system like ShakeAlert, there are numerous fundamental questions that still remain. Among these, the most important ones include how well dynamic strains in the fiber represent true ground strain, how signals within the FO array vary due to coupling and site effects, quantifying detection limits in frequency space, isolating seismic signals from natural and anthropogenic noise, the performance of FO systems in the near-field, optimal array geometries and sampling configurations, and differences in performance related to fiber engineering.
The purpose of this Mendenhall Fellowship opportunity is to advance our understanding on fiber optic seismology for earthquake early warning applications using array processing techniques. In particular, we are seeking a Fellow who can help address some of the major outstanding questions (listed above) based on recently acquired marine and terrestrial datasets, while helping prepare for upcoming deployments. A successful applicant should have the background and interest to pursue related research on distributed acoustic sensing of earthquake waves with fiber optic cables and with traditional seismic arrays for EEW. There are numerous possible research projects that could help us understand these issues, but there should be a focus using seismic array processing techniques with either FO or traditional seismic arrays.
The ShakeAlert EEW system is live in California, Oregon, and Washington. It relies on methods that are well optimized for dense seismic networks. However, many of the largest earthquakes that could produce shaking within the ShakeAlert reporting region will occur outside of the well instrumented areas, such as offshore in the subduction zone. Properly characterizing these earthquakes as quickly as possible presents one of the greatest opportunities for success in EEW and more active research is needed to improve the methods used for these difficult to instrument regions. Method development can be done using a growing number of publicly available fiber optic and traditional seismic array datasets. There will also be opportunities to design and collect new datasets during the term of the fellowship.
Dr. McGuire can supervise matters pertaining to array processing theory and the earthquake early warning system. Dr. Barbour can supervise matters pertaining to strain data processing and comparisons. Dr. Yoon can supervise matters related to processing large datasets and phase detection algorithms. The advisors will look for opportunities for the Fellow to gain a variety of research experiences and provide opportunities for the Fellow to collaborate and share their work with USGS offices outside of Moffett Field, including the Pasadena, Seattle, and Golden offices, for example.
Interested applicants are strongly encouraged to contact the Research Advisor(s) early in the application process to discuss project ideas.
Proposed Duty Station: Moffett Field, California; Pasadena California; Vancouver, Washington
Areas of PhD: Those providing experience with seismic array processing, distributed acoustic sensing applied to fiber optic cables, real-time data, strainmeters, earthquake early warning, and managing large data flows. (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 the qualifications for: 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 Human Resources specialist.)
Human Resources Office Contact: Audrey Tsujita, 916-278-9395, email@example.com