Unified Structural Representation (USR)
The Structural Representation group develops unified, three-dimensional representations of active faults and earth structure (velocity, density, etc.) for use in fault-system analysis, ground-motion prediction, and hazard assessment. This year’s efforts will focus on making improvements to existing community models (CVM, CVM-H, CFM, CBM) and evaluating alternative structural representations. We will also support the use of these models in various aspects of earthquake science by other working groups in SCEC.
- Community Velocity Model (CVM): Improve the current SCEC velocity models (CVM and CVM-H), with emphasis on more accurate representations of Vs and density structure, basin shapes, and attenuation. Generate more accurate descriptions of near-surface property structure that can be incorporated as geotechnical layers within the community models. Make the models compatible with fault positions and displacements as represented in the CFM. Evaluate the models with data (e.g., waveforms, gravity) to distinguish alternative models and quantify model uncertainties. Generate integrated northern and Southern California models.
- Community Fault Model (CFM): Improve and evaluate the CFM, placing emphasis on: a) defining the geometry of major faults that are incompletely, or inaccurately, represented in the current model; b) producing alternative fault representations; and c) providing more detailed representations of fault terminations and linkages. Evaluate the CFM with data (e.g., seismicity, seismic reflection profiles, geodetic displacement fields) to distinguish alternative fault models. Integrate northern and Southern California models into a statewide fault framework, and update the CFM-R (rectilinear fault model) to reflect improvements in the CFM.
- Unified Structural Representation (USR): Develop a flexible delivery system for the USR and its model components. Generate new versions of the Community Block Model (CBM) that support efforts in fault systems modeling. Produce a library of USR components, including faulted and folded horizons (as strain markers and property
boundaries) that are compatible with the CBM, CVM, and CFM.