1. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Statewide 3D Community Fault Model (SCFM) A statewide community-based, object-oriented, 3-D representation of active faults in California. Presentation Outline 1) Model overview 2) Model components 3) Fault construction 4) Model updates … for use in: Fault systems analysis Seismic hazard assessment...

2. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA SCFM Overview consists of SoCal and NoCal CFMs community models Includes alternative representations > 270 faults represented variable detail consistent base of model (base of seismicity) Distributed through website: http://structure.harvard.edu/cfm/ derived models: CFM-R, trace maps

3. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA SCEC Community Fault Model, NoCal Version 1.5 available > 110 faults represented Includes alternative representations iterated through workshop available for review via SCEC-VDO

4. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA SCEC Community Fault Model, SoCal Version 4.0 preview available > 150 faults represented Includes alternative representations Virtual Workshop evaluated model & ranked alternative fault representations (via LA3D) Widely used in fault system, strong ground motion, & seismic hazards studies in SCEC.

5. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA CFM components and architecture Triangulated surface fault representations flexible representation simple ASCII format Regional topographic surface USGS DEM (1:250,000 – 60m) SoCal SRTM DEM (90m) NoCal Seismogenic thickness surface Nazareth & Hauksson (2004) SoCal based on Waldhauser (2009) DD catalog NoCal

6. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Seismic profiles (1), wells (2), geologic data (3), and cross sections (4) are assembled and geo-referenced, as well as hypocenters (5) and focal mechanism (5). Fault surfaces are interpolated (a) and extrapolated (b) to define CFM representations. Extrapolated extents can be classified as connectors. Fault surfaces are extrapolated Plesch et al., 2005 Generating fault surfaces

7. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Generating fault surfaces, from a trace and a dip estimate A trace is digitized from a geo- referenced map or assembled from Qfaults and projected to the topographic/bathymetric level. A length (eg. 2000m) filtered trace is shifted along the dip to a first depth level (eg. 3km), and a coarser trace to a deep level (eg. 10km). All traces are then connected to a continuous fault surface. View from below filtered trace Digitized trace filtered trace

8. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Alternatives represent substantially different geometric definitions of a fault surface Alternative 1 Alternative 2 Newport-Inglewood fault Whittier & Chino faults Varying degrees of detail … Different styles of fault interaction at depth …

9. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Each version of CFM represents a set of specific alternative representations for each fault Unique fault name and number Alternative 1Alternative 2 Interpolated 1 Interpolated 2 Extrapolated 1 Interpolated 1 Interpolated 2 Extrapolated 1 Extrapolated 2 … preferred … Alt. 1Alt. 2 Ext. 1 Ext. 2 Ext. 3 N

10. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA CFM Fault Attributes In the database, each alternative representation will have a unique set of attributes assigned to it, including: fault type (rl or ll strike-slip, thrust,normal, oblique …) surface or blind designation, connector average spatial uncertainty qualitative assessment of representation (1-5) slip rate range (CGS/SCFAD) primary reference list date generated The database can be queried using these attributes.

11. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Model updates Southern San Andreas: - seismicity based updates - compliance with Qfaults improved Borderlands: - alternative representations of thrusts which allow for all modes of interaction with strike- slip faults.

12. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Model updates in progress Revision of naming and numbering system: - hierarchical: Peninsular Ranges – San Jacinto fault – San Bernardino section – San Jacinto-Claremont fault – vertical - meaningful numbers: two digits for each level - reflects system behaviour

13. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Model updates, UCERF3 relevance Southern San Andreas: - additional sources Blind Palm Springs fault North Palm Springs fault Mecca Hills - Hidden Springs fault - modified sources that allow multiple paths for SAF rupture Banning Garnet Hill San Gorgonio Pass Mission Creek Borderlands: - discussed in dedicated presentation

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16. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Regional overview SF Bay area

17. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Regional overview S. Coast Ranges/S Joaquin Valley

18. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Regional overview S. Coast Ranges/S Joaquin Valley

19. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Regional overview Sierra Nevada/Mammoth/Long Valley

20. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Regional overview Sierra Nevada/Mammoth/Long Valley

21. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Regional overview N. Coast Ranges/Sacramento Valley

22. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Regional overview N. Coast Ranges/Sacramento Valley

23. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Regional overview Cascadia/Klamath Mountains/Modoc

24. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Regional overview Cascadia/Klamath Mountains/Modoc

25. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Nazareth & Hauksson (2004) use the depth where 99.9% of the total moment in a vertical column was released Steps: Selection of events Gridding and computation Filtering of low quality cells Smooth interpolation Seismogenic thickness surface for NoCal

26. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Seismogenic thickness surface for NoCal Central Valley has little seismicity in some places. Mask nodes in depth surface which are more than 30 km away from closest grid point used in interpolation.

27. E ARTHQUAKE C ENTER S OUTHERN C ALIFORNIA Generating fault surfaces, from the USGS Bay area model and Qfaults Bay area model fault is extracted and compared to Qfault representation. The top of the fault is adjusted to conform to topography, and its length adjusted to conform to Qfaults. Hayward representation in SCFM Qfault trace Calaveras representation in SCFM Rogers Creek representation in SCFM Hayward representation in Bay area model