CFM Version 5.1: New and revised 3D fault representations and an improved database.

Andreas Plesch, Craig Nicholson, Christopher C. Sorlien, John H. Shaw, & Egill Hauksson

Published September 11, 2016, SCEC Contribution #6768, 2016 SCEC Annual Meeting Poster #003 (PDF)

We present an updated version of the SCEC Community Fault Model (CFM) for southern California. For version 5.1, we focused on improving the database component of CFM which is critical for the internal consistency and maintainability of the model. This system also enables model consumers to access and assess the full richness of the various modeled fault systems and their alternative 3D fault representations. The improved database now contains more than 800 rows of named fault-component objects organized in a sensible hierarchical scheme. These components are fault sections, splays and strands comprising faults and fault systems. The database is now synchronized with the latest catalog of individual t-surf CFM fault representations. This synchronization included recent updates to the database with over 300 new fault-component objects developed for the San Andreas fault system and Eastern Transverse Ranges, Mojave & Offshore Continental Borderland fault areas. Through this process, we identified more than 30 fault components that needed updating and were improved either by developing new 3D alternative fault models or by better regularization of their 3D fault surface meshes. as well as by a more consistent assignment to suitable locations in the hierarchical system. In addition, important independent fault attributes such as average strike and dip and the fault's equivalent USGS Quaternary Fault (qfault) id association were updated to reflect any changes in underlying fault geometry.

As a result, many new or updated 3D representations were added to CFM in the Mojave and Eastern Transverse Ranges fault areas, together with updated, revised models for the Newport-Inglewood-Rose Canyon fault system and faults in the Western Transverse Ranges associated with the Ventura Special Fault Study Area. These fault updates in CFM include extending the active North Channel-Pitas Point-Red Mountain fault system west to Pt. Conception, updating the geometry of the offshore Oak Ridge and Mid-Channel faults, and incorporating sub-horizontal faults linked to S-dipping faults in the western, eastern, and mid-channel areas, including the Hondo, Padre Juan & Oak Ridge faults based on mapping with industry seismic reflection data. Further, a number of these faults were extended to greater depths with available relocated seismicity.

Key Words
USR, faulting, structure, CFM

Citation
Plesch, A., Nicholson, C., Sorlien, C. C., Shaw, J. H., & Hauksson, E. (2016, 09). CFM Version 5.1: New and revised 3D fault representations and an improved database.. Poster Presentation at 2016 SCEC Annual Meeting.

Related Projects & Working Groups
Unified Structural Representation (USR)