SCEC2021 Plenary Talk, SCEC Community Models (CXM)

The SCEC community fault model: challenges, progress, and the future

Scott T. Marshall, Andreas Plesch, & John H. Shaw

Oral Presentation

2021 SCEC Annual Meeting, SCEC Contribution #11247 VIEW PDF
The Community Fault Model (CFM) is one of SCEC’s most established and widely used resource with applications in many aspects of SCEC science including crustal deformation modeling, wave propagation simulations, and probabilistic seismic hazards assessments. The CFM also directly contributes to other community modeling efforts, including the Geological Framework, Community Rheologic, and Community Velocity Models.

In the most basic sense, the CFM contains a hierarchically-organized set of three-dimensional (3D) representations of hazardous faults in southern California and adjacent offshore basins. Currently, the preferred fault set in version 5.3 includes 440 individually named fault representations (alternative representations are also provided). A significant challenge of creating and updating the CFM is that most of these fault representations need to be constructed manually. Where sufficient seismicity and other data constraints exist, semi-automated methods have recently been developed that offer promise to generate objective and reproducible 3D fault representations. Another challenge is that each fault object has numerous components including: metadata (information about the fault, geometry, and references), several different 3D surface representations (in separate files), and fault trace data (in several different formats). We have therefore developed a set of semi-automated scripts that test various components of the model for accuracy and self-consistency. An additional challenge is that there is no generally agreed upon standard file format for 3D fault surfaces, and many 3D software packages are expensive and/or require difficult to manage licenses. We provide 3D objects in the Gocad t-surf format, a simple human-readable format that users can parse into whatever format is needed for their workflow. To facilitate wider use of the CFM, we have developed a suite of web-based tools that allow users to query, download, and visualize the CFM. These new web-based tools notably include a 3D interactive viewer and the option to visualize relocated seismicity in both 2D and 3D views.

Reflecting the nature of the CFM as a community model, we are in the process of organizing a community evaluation of CFM5.3. This will allow the SCEC community to provide direct feedback and ratings to CFM objects. The results of this community evaluation will be used to construct the CFM version 6.0.