- To conduct hazard sensitivity studies to assess the importance of factors, models and parameters that affect the ground motion hazard.
Hazard Feedback Analyses (HFAs) represent a critical task that will ensure that the project team stays focused on issues that affect the ground motion hazard. The analyses essentially consist of a series of sensitivity studies on models and/or parameters used to develop the models. HFAs will be conducted throughout the project and key results will be presented at each workshop to help the project keep the focus on the key factors that control the hazard. The TI team plans to use a dual approach for the HFAs. The TI team will coordinate with the USGS to use their implementation of the CEUS SSC model and run their own analyses. However, it is anticipated that the USGS software may only include a simplified implementation of the CEUS SSC model, and a second team of external HFAs was selected to conduct additional analyses with the complete source model. This dual process will allow the TI team the flexibility to easily run regular analyses while the second set of analyses will ensure that the TI team conclusions are also consistent with the complete source model implementation.
The hazard feedback for GMPEs needs to consider the magnitude and distance contributions from the different tectonic environments in CENA. The plan is to coordinate with the CEUS SSC project and possibly include the seven test sites that were used for the CEUS SSC hazard feedback. The seven sites were previously selected by the CEUS SSC to capture the range of tectonic environments and are appropriate for use in the ground motion hazard feedback. The goal is to use the sites to illustrate the relative importance of various components of the GMC model to seismic hazard. The final site selection will also depend on the regionalization models selected.
As mentioned above, the HFAs will be conducted regularly and presented at the workshops. An “M” superscript is shown next to the key tasks where HFAs are anticipated (see complete flowchart). This list of tasks is not exhaustive and the need for HFAs will be regularly re-assessed by the TI team throughout the project.