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The SCEC Community Fault Model (CFM)

CFM WORKING GROUP
CXM Representative
Scott Marshall
SCEC Software Team
Mei-Hui Su
Phil Maechling
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A web-based data access tool that provides 2D map view and 3D view of the SCEC CFM5.3 preferred fault set. Users can view and download fault geometry metadata for selected faults.
 
 
SCEC CFM NOTIFICATIONS
Service that emails subscribers near real-time after a ≥M3 event and provides the most likely CFM fault(s) that generated the earthquake.
See this article for more information and how to subscribe.
 
SCEC COMMUNITY MODELS
RELATED RESEARCH
WORKSHOPS
September 10, 2017
January 25, 2008
March 27, 2003
Perspective view of the CFM5.3 with fault surfaces colored by strike. Relocated seismicity is colored by time (calendar year). (Hauksson et al., 2012, and 2019 updates)

Introduction

The SCEC Community Fault Model (CFM) is an object-oriented, three-dimensional representation of active faults in southern California and adjacent offshore basins that currently includes 440 individually named fault representations in the preferred model. Including alternative representations, the model incorporates 1186 objects. For the preferred fault set (440 surfaces), each fault object consists of  triangulated surface representations (t-surfs) in several resolutions, fault traces in several different file formats, and complete metadata including references used to constrain the surfaces. The CFM faults are defined based on all available data including surface traces, seismicity, seismic reflection profiles, well data, geologic cross sections, and various other types of data and models. The CFM serves the Southern California Earthquake Center (SCEC) as a unified resource for physics-based fault systems modeling, strong ground-motion prediction, and probabilistic seismic hazards assessment (e.g., UCERF3). Together with the Community Velocity Model (CVM-H 15.1.0), the CFM comprises SCEC's Unified Structural Representation of the Southern California crust and upper mantle (Shaw et al., 2015).

Current Model Version: CFM5.3

The latest release of the CFM is version 5.3, which includes many new and revised fault representations, notably in the Ridgecrest and offshore regions (Plesch et al. 2020). In addition, the new model has greatly expanded and improved the metadata component of CFM to help ensure the internal consistency and maintainability of the model. Automated scripts now check for consistency with filenames and the various metadata components. CFM fault objects follow a hierarchical naming system that enables model users to easily sort the model by region and subregions. The expanded metadata now includes fault surface areas, area-weighted average strike/dip values, expected sense of slip, and references for each fault object. Additionally, the expanded metadata includes fields  the equivalent USGS Quaternary fault (Qfault) ID, when available. See the README.txt file in the root directory of the archive for information about the directory structure and contents of the entire zipped archive.

Download the complete CFM5 archive (ZIP, 64MB)

CFM5.3 Web Viewer and Query Tool

To facilitate use of the model, we have created a web-based CFM model viewer which can be accessed at the link below. The CFM web-viewer allows users to visualize the CFM in a 2D map-based view, or in a 3D CAD-like environment. The model can be searched/filtered/downloaded based on a number of user criteria.

2D Map Viewer Video Tutorial Plot3D Video Tutorial

GO TO CFM VIEWER

Fault Trace Maps of the CFM5.3

While the CFM is an inherently three-dimensional subsurface model, users may wish to locate various CFM faults relative to geographic features on a two-dimensional map. Here, we provide several two-dimensional map-based visualizations of the fault traces and upper tip lines (for blind faults) of the CFM5.3. Digital Elevation and Bathymetry Models (DEM) were derived from the USGS 3DEP, and GMRT data, and the maps were produced using the open source Generic Mapping Tools software package.

 2D Map-Based Visualization Download
CFM5.3 basic map (no topography) PDF, 152KB
PNG, 504KB
CFM5.3 with grayscale shaded DEM PDF, 3MB
PNG, 5MB
CFM5.3 with color shaded DEM PDF, 5MB
PNG, 6MB
CFM5.3 with color shaded DEM and bathymetry PDF, 7MB
PNG, 7MB

If you would like to create your own CFM5.3 map, the fault trace data is currently available for download in shapefile, Google Earth kml, and Generic Mapping Tools multi-segment ASCII format. These files can be found in the CFM dataset in the obj/traces and subdirectories.

Software for Visualizing the CFM

While the data for the CFM fault surfaces are stored in plain text gocad files, visualizing the CFM can pose challenges to new or even seasoned users. Below is a list of software packages that can be used to visualize gocad t-surf files in 3D.

  • SKUA-GOCAD: This is the main software package used to build and maintain the CFM. SKUA-GOCAD software requires a license and is not freeware.
  • The Petroleum Experts Move Suite: Move requires a license, but is available at no charge to qualifying academic institutions. Move can directly import gocad t-surf files and has tools for manipulating fault meshes.
  • The SCEC VDO: The SCEC-VDO is a free 3D visualization software package that was designed by researchers and undergraduate interns at SCEC. Currently, the SCEC-VDO appears to only work properly with the CFM for users running Windows 7, and Mac OS X. We have created a README file with instructions on how to view the CFM in 3D using the SCEC-VDO.

What is a GOCAD file and what can I do with it?

The three-dimensional CFM fault surfaces are provided in the GOCAD t-surf ASCII file format. While this file format is likely unfamiliar to most users, the basic structure of the files is relatively straightforward and human-readable. Here, we provide a document with some answers to frequently asked questions about the GOCAD t-surf file format.

Download GOCAD t-surf file FAQ (PDF, 177kB)

Community Created and Open Source CFM Tools

Below are several tools created by various CFM users that we hope will prove useful when attempting to parse and/or visualize aspects of the CFM.

  • Scripts provided by Scott Marshall (Appalachian State University) - Download (Google Drive Link to ZIP archive file)
    • plotMesh.m : A MATLAB function that plots a CFM surface using either a single gocad t-surf file, or the .xyz and .tri files created by ts2matlab.pl.
    • ts2facet.pl : A Perl script that parses a .ts file into a .facet file which can be directly imported by Cubit/Trelis and some finite element codes.
    • ts2matlab.pl : A Perl script that parses a .ts file into an .xyz and .tri file that are easy to read into MATLAB using the load function.
  • ReadAndSaveCFM : A Python script to read and load tsurf files (*.ts) into MATLAB. This script is based on the matlab script ReadAndSaveCfm.m by Brendan Meade.

CFM Fault Association Notifications After an Earthquake

SCEC collaborators from Harvard and Caltech developed a statistical method to rapidly identify the most likely fault (or sets of candidate faults) in the CFM that generated an earthquake (Evans et al., 2020) . The approach has been applied to the full SCSN catalog (M ≥ 3.0) using CFM (5.2), and probabilities of association between every earthquake in the catalog and each fault in the CFM are available at the Southern California Earthquake Data Center. For a description of the method, see this article.

Members of the SCEC community can sign up to receive SCEC CFM association information through email. This service will notify you each time there is an ≥M3 event and provide fault associations. An aftershock suppression system was implemented, so your inbox doesn’t get overloaded! A SCEC.org account is required to receive notifications. To subscribe to this service, update your SCEC user profile to include “CFM Fault Association Notifications”. Check the box next to the Mailing List Subscriptions and click “SAVE” at the bottom of the page.

Previous Model Versions

We encourage users to use the current CFM version; however, we recognize that some users may still be using an old model version and some CFM versions have been published, we provide links to download past versions below.

CFM5.2

CFM5.2 included many new and revised fault representations (Nicholson et al., 2017). In addition, CFM5.2 contained an expanded metadata component including a hierarchical naming and numbering system that enabled model users to easily sort the model. Metadata also contains USGS Quaternary fault (Qfault) ID, and fault attributes of average strike, dip, area, and faulting style where available. See the README.txt file in the root directory of the archive for information about the directory structure and contents of the entire zipped archive.

Download the legacy CFM5.2 archive (ZIP, 52MB)

CFM4

The compressed zip archive available for download contains version 4 of the SCEC Community Fault Model (CFM). The archive includes a poster presentation that has details on the many updates and improvements for this fault model. Highlights include revisions based on the the recently completed USGS QFault trace database with a focus in the San Gorgonio Pass and St. Barbara/Ventura Basin areas. In addition, the archive contains a fault database spreadsheet which lists all faults with their associated USGS (qfaults) ID and the average of quality factors assigned to each of the alternative fault representations by a group of experts after evaluation of the model. These factors were used to rank fault representations where multiple alternatives were constructed for a given fault. The highest ranked fault representations are grouped into a preferred fault model. See the README.txt file in the root directory for information about the directory structure and contents of the archive.

Download the legacy CFM4 archive (ZIP, 12MB)

CFM3

The compressed zip archive contains version 3 of the SCEC Community Fault Model (CFM). Version 3 was the first version which was fully evaluated and where alternative fault representations were ranked to select a preferred model consisting of more than 140 faults. The model is described and illustrated in the BSSA manuscript by Plesch et al., 2007, which is included in the doc directory. In addition to tsurf and kml files of the preferred model, the archive contains all alternative fault representations, a derived fault trace map in a GIS compatible format, and documentation. Please see the included README.txt file in the root directory for information about the directory structure and contents of the archive.

Download the legacy CFM3 archive (ZIP, 17MB)

References