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The SCEC Community Fault Model (CFM)

CFM WORKING GROUP
SCEC Software Team
Mei-Hui Su
Phil Maechling
CFM Contributors
We could not make the CFM without support from the community of CFM contributors.
Do you have new data or interpretations that constrain the 3D geometry of CFM faults? Find out how to contribute to the CFM!
CFM Evaluators
We would like to thank those that volunteered their time and expertise to the rigorous evaluation of the CFM during the devlopment of version 6.1.
DOWNLOADS
DOI
Previous Models
SOFTWARE SUPPORT
DATA ACCESS TOOL
A web-based data access tool that provides 2D map view and 3D view of the SCEC CFM6.1 preferred fault set and other models. 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 CFM6.0 with fault surfaces colored by the fault system. Relocated seismicity is colored by time (calendar year). (Hauksson et al., 2012, and 2019 updates)

Introduction

The SCEC community fault model: challenges, progress, and the future by Scott Marshall as presented at the 2021 SCEC Annual Meeting

The SCEC Community Fault Model (CFM) is an object-oriented, three-dimensional representation of active faults in southern California and adjacent offshore basins. For each fault object, the CFM provides triangulated surface representations (t-surfs) in several resolutions, fault traces in several different file formats (shape files, GMT plain text, and GoogleEarth kml), 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: CFM6.1

The current version of the SCEC Community Fault Model version 6.1 (CFM6.1) and is partially the result of a community evaluation of CFM5.3. CFM6.1 serves as the latest update to Plesch et al. (2007) and builds on previous CFM releases. New to CFM6.1 are two additional separate and fully-documented sub models: the ruptures and alternatives model. In total, CFM6.1 comprises the following components: 
  1. The CFM6.1 Preferred Model: a set of 443 fault objects that constitute the preferred set of active faults in southern California.
  2. The CFM6.1 Rupture Model: a set of 13 fault objects assembled from the CFM6.1 preferred model that ruptured during selected significant historic events. These are not earthquake source models, but are representations of the entire fault surfaces where a significant historic rupture occurred. This model is intended to indicate which CFM fault objects were involved with selected significant historic ruptures.
  3. The CFM6.1 Alternatives: a set of 38 alternative representations where structural differences have been proposed that could potentially significantly impact fault mechanics and associated seismic hazards. These alternative representations were selected based on community rankings following a comprehensive evaluation of the CFM that took place in May of 2022.
Including all sub models, the CFM6.1 incorporates 494 fully-documented objects. If you use the CFM, we would appreciate you citing the DOI where the archive is stored. Use the link below.
 

CFM6.1 Change Log

CFM6.1 differs from CFM6.0 in several ways, as described below.
  1. The Southern San Andreas fault was updated to the dipping model based on Fuis et al., (2012) which also contains a portion of the Banning fault.
    • SAFS-SAFZ-MULT-Southern_San_Andreas_fault_and_Banning-CFM6 is now the preferred representation. Naming of this object is challenging because this object contains both what is typically referred to as the Southern San Andreas fault and a portion of the Banning fault. This is included in the metadata comments.
    • SAFS-SAFZ-COAV-Southern_San_Andreas_fault-CFM4 (Steeply dipping) is now an alternative representation, SAFS-SAFZ-COAV-Southern_San_Andreas_fault-ALT6.
  2. The East Shoreline fault has been shortened to not extend north of Mecca Hills. 
    • SAFS-SAFZ-COAV-East_Shoreline_fault-CFM6 is the preferred version (same name in CFM6.0) and now no longer extends north of Mecca Hills. This is consistent with Janecke et al. (2019) where north of Mecca Hills the fault presence and location is mapped as speculative.
    • The longer SAFS-SAFZ-COAV-East_Shoreline_fault-CFM5 is now provided as an alternative, SAFS-SAFZ-COAV-East_Shoreline_fault-ALT6.
  3. The Malibu Coast fault (east segment) has been truncated and merges with the Malibu Coast fault (west segment) and no longer extends farther to the west. The object name, WTRA-SFFS-SMMT-Malibu_Coast_fault_east-CFM6, remains the same.

CFM Archive Contents

Did you know that the CFM archive contains more than just 3D fault data? Below is a simplified list of the archive contents.
  • 3D GOCAD t-surf files for each fault object in four different resolutions (native, 500m, 1000m, and 2000m)
  • Fault trace data in GIS shapefile and Generic Mapping Tools (ASCII) formats.
  • Google Earth KML version of the fault traces. Selected metadata pops up when a fault is selected.
  • Metadata spreadsheet (Microsoft Excel format), and a CFM6.1-References (Microsoft Word format) with full references.
  • Two README.txt files that explain the CFM archive directory structure and hierarchical naming system.

CFM 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. The CFM web viewer and query tool currently hosts the CFM6.1 preferred, CFM6.1 ruptures, CFM6.1 alternatives, and the CFM5.3 preferred models. Users can click on the buttons above the map interface to select the desired model. To view plots in 3D, users must first select the desired faults and then click the plot3D button near the bottom right of the interface.

GO TO CFM VIEWER

Tutorial Videos

2D Map Viewer Video Tutorial Plot3D Video Tutorial

 

Fault Trace Maps of the CFM6.1

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
CFM6.1 basic map (no topography) PDF, 101KB
PNG, 300KB
CFM6.1 with grayscale shaded DEM PDF, 2.9MB
PNG, 5MB
CFM6.1 with color shaded DEM PDF, 4.8MB
PNG, 5.7MB
CFM6.1 with color shaded DEM and bathymetry PDF, 6.4MB
PNG, 7.2MB

If you would like to create your own CFM 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 DOI archive under the obj/preferred/traces and associated subdirectories.

User Submission Form for New Fault Data

In order to have the most up to date knowledge included in future CFM versions, we need assistance from the SCEC community. If you have or are aware of recently published data that constrains the three dimensional fault geometry in California, please fill-out the CFM user submission form linked below. Please keep in mind that creating 3D fault representations is not automated and takes considerable time and effort, so any submissions may take until the next major release to be considered for incorporation into the CFM.

CFM User Submission FORM

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.
  • MiraGeoscience: Free 3D visualization and communication software for integrated, multi-disciplinary geoscience and mining data and models.

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.

CFM5.3 (2022)

CFM5.3 included 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, USGS QFault ID, and references for each fault object. 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)

CFM5.2 (2017)

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 (2014)

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 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 (2006)

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)

CFM Contributors

The current and past versions of the CFM would not be possible without contributions from numerous SCEC community members. We would like to thank the following CFM contributors:

Christine Benson, William Bryant, Sara Carena, Michele Cooke, James Dolan, Jessica Don, Gary Fuis, Eldon Gath, Judith Hubbard, Susanne Janecke, Yuval Levy, Lisa Grant Ludwig, Egill Hauksson, Thomas Jordan, Marc Kamerling, Mark Legg, Scott Lindvall, Harold Magistrale, Scott Marshall, Jonathan Matti, Craig Nicholson, Nathan Niemi, Michael Oskin, Sue Perry, George Planansky, Andreas Plesch, Thomas Rockwell, John Shaw, Peter Shearer, Christopher Sorlien, M. Peter Süss, John Suppe, Jerry Treiman, Franklin Wolfe, Robert Yeats, and every colleague that has participated in a CFM community evaluation. We could not make the CFM without this community effort.

CFM Evaluators

Before assembling CFM6.1, a team of SCEC colleagues participated in a rigorous evaluation of CFM5.3 in April-May of 2022. This evaluation was open to the SCEC community and focused on 23 critical fault representations where different proposed interpretations have the potential to significantly affect seismic hazards. This evaluation resulted in 14 new fault representations in the CFM6.1 preferred model. The lower ranked representations are now provided in the CFM6.1 alternative model. We would like to thank the following CFM evaluators for volunteering their time and expertise to this process:
 

References