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Prehistoric earthquake records provide necessary information for probabilistic models such as the USGS National Seismic Hazard Model. In intraplate tectonic settings, paleoseismic data typically originate from terrestrial (fault-trench) studies and can be limited by broad earthquake-timing uncertainties, short and/or incomplete temporal records, and a narrow earthquake magnitude observational window. In contrast, lacustrine paleoseismic data have the potential to yield continuous, high-fidelity earthquake shaking records over a broader magnitude range. Despite the promise of lacustrine paleoseismology methods, uncertainty remains regarding shaking-intensity and magnitude thresholds for the formation of lake sediment disturbance deposits, tectonic versus nontectonic triggering mechanisms for these disturbance events, and how multiple possible seismogenic fault sources can be distinguished. As a result, their use in constraining regional seismic hazard models has been limited. There is thus a need to develop and test hypotheses related to how lacustrine, terrestrial, and geophysical data can be integrated to generate high-resolution and robust prehistoric earthquake histories.
The focus of this Mendenhall Research Opportunity is to generate new lacustrine paleoseismic data, and in concert with previous geologic and geophysical data, develop defensible constraints on the timing, location, and intensity of earthquakes in regions of elevated seismic hazard. We encourage candidates to address scientific questions in quantitative lacustrine paleoseismology using new and previously established methods and data. For example, research could focus on exploring sediment disturbance processes and triggering mechanisms, comparing historical and prehistoric disturbance deposits, and/or advancing methods of extracting long, continuous records and testing models of earthquake recurrence. Successful candidates will consider multiple hypotheses, leverage multiple methods, develop new quantitative tools, synthesize both terrestrial and lacustrine geological and geophysical data, and produce results that are of broad interest to the paleoseismological community.
We seek a postdoctoral candidate to conduct research on lacustrine paleoseismology and address problems related to establishing earthquake histories using multiple geological and geophysical approaches. The research effort will be largely determined by the postdoctoral fellow’s background and interests but ideally will broadly align with our goals to quantify regional seismic hazard using lacustrine basins in intraplate settings in the conterminous U.S.
The scope of research could include, but is not limited to:
- Exploring internal (e.g., basin and sediment related) and external (e.g., earthquake source and shaking intensity) controls on the formation of earthquake-related sediment disturbance (e.g., turbidity) deposits in lacustrine basins.
- Distinguishing between disturbance events formed by tectonic and nontectonic (e.g., storm or landslide related) triggering mechanisms.
- Calibrating lake sediment response to strong shaking in high- and low-relief basins using historical earthquake shaking intensity data.
- Using multiple approaches such as reflection seismology, sediment coring, and geochronology to establish earthquake histories for high-hazard regions.
- Synthesizing new and previous lacustrine and terrestrial geologic and geophysical data for intraplate regions such as the Wasatch Front (Utah), Teton Range (Wyoming), Pacific Northwest, or Central and Eastern U.S.
Interested applicants are strongly encouraged to contact the Research Advisor(s) early in the application process to discuss project ideas.
Proposed Duty Station: Golden, Colorado or Santa Cruz, California
Areas of PhD: Geology, paleoseismology, seismology, geochronology, geophysics, 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 the qualifications for one of the following: Research Geologist or 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: Megan Agy, 303-236-9584, magy@usgs.gov
