Description of the Research Opportunity
An ongoing, fundamental challenge in real-time operational seismology at the USGS National Earthquake Information Center is rapidly ascertaining the fault geometry and rupture characteristics necessary for accurate shaking (and thus loss) estimates. The goal of this research and development is to expedite and improve the accuracy of the fault models used for USGS/NEIC ShakeMap and PAGER loss estimates. Worldwide, numerous government agencies (including USAID), emergency response, aid, nonprofit organizations, financial decision-makers, the public, and media depend on ShakeMap and PAGER shaking and loss estimates for post-earthquake response. Improved finite-fault models can also contribute to situational awareness, reconnaissance planning, more sophisticated ground motion prediction strategies, ground failure estimates, static displacement fields, and prediction of tsunami potential.
For large earthquakes, many users now expect the USGS/NEIC to provide an initial faulting rupture geometry within a few hours of an earthquake, and subsequent updates that trend towards the true faulting geometry and rupture complexity within a few days. Any tools that can facilitate more timely and accurate rupture information are solicited. However, it is anticipated that any new framework proposed will contribute to aggregating currently disparate inputs that vary in availability, timeliness, and accuracy from event to event. For example, a standard tool for recovering finite-fault dimensions is finite-fault inversion employed at NEIC (e.g., Goldberg et al., 2023). However, available faulting geometry and other constraints at the initiation time of the inversion an hour or so after the origin are often lacking. They could be improved with consideration of both prepositioned constraints (namely nearby active fault geometry and their slip rates, fault geometries and scaling relationships), real-time inferences from, for example, early aftershock characteristics, and response timeframe inferences from, for example, fault orientation from InSAR data.
In addition to existing fault geometries, other anticipated inputs to constrain the rupture characteristics needed to predict shaking include, but are not limited to (i) evolving aftershock patterns, (ii) teleseismic back-projection results, (iii) fault dimensions from scaling relations, (iv) GNSS observations, (v) optical and radar (both coherent changes and changes in coherence) imagery, (vi) interpretations of first-motion and moment-tensors, (vii) ground motion and intensities data themselves, or as employed in FinDER (or similar approaches). Any proposed strategy must consider that these potential constraints will only be available or helpful under some circumstances (e.g., some events and not others, different post-event delay times, etc.), so default approaches must not depend on any one particular dataset being available.
Prepositioned fault models could be part of a rupture set (as used in Probabilistic Seismic Hazard Analyses, PSHA) or active fault databases depending on the degree of understanding of the region’s seismotectonics. For instance, rupture segments extracted from mapped subduction interfaces (e.g., Slab2) could serve as the starting geometry for a finite fault inversion with clever assumptions. Conversely, event sets from PSHA models could serve as a logical starting point for a large crustal event. However, there are no guarantees that such simple assumptions will prove beneficial for all events, and care must be taken to avoid strict assumptions by evaluating and weighting input from evolving, complementary models and observations.
Possible approaches may include existing fault databases, collaborative input constraints, potentially incorporating formal expert elicitation, educating potential contributors of the need for their input, an operational dashboard, or other innovative strategies. However one approaches this opportunity, the elements that will be prioritized will likely depend on the proposed strategy, the expertise of the applicant, initial investigations into available datasets, collaborative inputs and constraints, and initial algorithm and modeling developments. Proof of concept and testing could come from replaying recent events for which such evolving constraints could have been made available if such a system was in place at the time of the events, but it may be logical to consider a wide range of alternative approaches.
Interested applicants are strongly encouraged to contact the Research Advisors early in the application process to discuss project ideas.
Proposed Duty Station(s)
Golden, Colorado
Areas of PhD
Geophysics, geology, geodesy, seismology, computer science 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 Geophysicist, Research Geologist, Computer Scientist
(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.)
