SONGS SSC Tom Freeman GeoPentech PRELIMINARY RESULTS
Focused Questions Summarize the tectonic setting What is the seismogenic thickness? Are you including deep ruptures in the upper mantle (~30 km)? Do you have splay faults or overlapping segments? Do you have complex multi-segment ruptures with different rakes/dips along strike? What is the largest magnitude in your sources (due to linked faults)? What is the range of dip angles (min & max) and faulting styles?
Tectonic Setting - Broad zone of deformation related to transition from transtensional to transpressional plate boundary - Deformation is distribution across many faults - Strike-slip and reverse/thrust faulting - How deformation is distributed is SSC SSHAC topic
SONGS PSHAs Past PSHAs: 1995, 2001, 2010 Efforts focused on key sources Current PSHA: Sources within 200 miles to be considered Per 10 CFR 100 Appendix A, 203 sources
PAST SONGS PSHAs Key Sources: Newport Inglewood/ Rose Canyon (NI/RC) Oceanside Blind Thrust (OBT) Palos Verdes/Coronado Bank Elsinore San Diego Trough San Jacinto San Andreas San Clemente
2010 PSHA & UCERF2 San Gorgonio Knot Malibu Coast Fault Legend SONGS Type A Faults Type B Faults Type C Zones from UCERF 2 Oceanside Thrust Non-Designated (ND) Faults(2) Oceanside Thrust from Sorlien et al. (2009b) NOTES: (1) Map is modified from Plesch et al. (2007), WGCEP (2008), Sorlien et al. (2009b), USGS (2008, 2009), and Conrad et al. (2010). (2) Parameters for faults being considered for development in future UCERF models. Fault traces from USGS (2009), Sorlien et al. (2009b) and Conrad et al. (2010). (3) Faults used in UCERF 2, USGS (2008), and SONGS 2010 PSHA are identified with black and bold letters. PRELIMINARY RESULTS March 2013
2010 SONGS Fault Models FM 1 Newport-Inglewood [Offshore] OBT is subsidiary Newport-Inglewood [Onshore] Rose Canyon San Joaquin Hills Carlsbad Palos Verdes Coronado Bank San Diego Trough Elsinore San Jacinto San Andreas Others Background FM 2 Oceanside Blind Thrust (OBT) N-I [Offshore] is subsidiary Newport-Inglewood [Onshore] Rose Canyon San Joaquin Hills Carlsbad Palos Verdes Coronado Bank San Diego Trough Elsinore San Jacinto San Andreas Others Background
2010 PSHA Seismic Sources Fault Name Oceanside Blind Thrust (OBT) Newport Inglewood/Rose Canyon (NI/RC) Closest Distance (km) Maximum Magnitude (Mw) Fault Mechanism Basis 6 7.1 to 7.6 Reverse 2010 PSHA 8 6.8 to 7.5 Strike-slip USGS, 2009 Palos Verdes/Coronado Bank 32 7.6 to 8.0 Strike-slip UCERF2 Elsinore 38 7.0 to 8.2 Strike-slip UCERF2 San Diego Trough 46 7.0 Strike-slip USGS, 2009 San Jacinto 70 6.7 to 8.3 Strike-slip UCERF2 San Andreas 92 6.9 to 8.5 Strike-slip UCERF2 San Clemente 94 7.2 Strike-slip USGS, 2009 Remaining Sources > 100 6.4 to 7.4 Strike-slip & Reverse UCERF2
2010 PSHA Source Contribution for PGA NI/RC OBT source contributes over 99% of total hazard contribution at AFE = 10-4 NI/RC OBT source contributes 100% of total hazard contribution at AFE = 10-6
Driving SSC Issue
Vintage Seismic Data NI/RC? PRELIMINARY RESULTS March 2013
NI/RC is Primary west OBT is Subsidiary SONGS east 8 km NI/RC NI/RC?
west OBT is Primary NI/RC is Subsidiary SONGS east NI/RC??
Focused Questions Summarize the tectonic setting What is the seismogenic thickness? Are you including deep ruptures in the upper mantle (~30 km)? Do you have splay faults or overlapping segments? Do you have complex multi-segment ruptures with different rakes/dips along strike? What is the largest magnitude in your sources (due to linked faults)? What is the range of dip angles (min & max) and faulting styles?
Nazareth & Hauksson (2004) Seismogenic Depths
Shallow crustal nucleations Adjacent offshore areas 6-10 km depths Adjacent coastal areas 7-16 km depths
Seismogenic Depths Past analyses considered up to 17 km Deep 30 km nucleations? will re-assess in current SSC SSHAC
Focused Questions Summarize the tectonic setting What is the seismogenic thickness? Are you including deep ruptures in the upper mantle (~30 km)? Do you have splay faults or overlapping segments? Do you have complex multi-segment ruptures with different rakes/dips along strike? What is the largest magnitude in your sources (due to linked faults)? What is the range of dip angles (min & max) and faulting styles?
Overlapping Fault Models OBT & NI/RC Simplified geometries Either may have splays OBT Northern Segment SONGS OBT Southern Segment
Splay Faults
Focused Questions Summarize the tectonic setting What is the seismogenic thickness? Are you including deep ruptures in the upper mantle (~30 km)? Do you have splay faults or overlapping segments? Do you have complex multi-segment ruptures with different rakes/dips along strike? What is the largest magnitude in your sources (due to linked faults)? What is the range of dip angles (min & max) and faulting styles?
Complex Linkages: OBT + NI/RC Two segments of OBT OBT Northern Segment OBT Southern Segment Both segments possibly linked to high-angle splays OBT Northern Segment OBT Southern Segment SONGS
Complex Linkages: OBT + NI/RC Three segments of NI/RC NI-Onshore NI-Offshore RC Segments possibly linked to lowangle splays OBT Northern Segment OBT Southern Segment SONGS
Complex Linkages: OBT + NI/RC OBT+NI/RC linkage Minor changes in fault strike Significant changes in fault rake OBT Northern Segment OBT Southern Segment SONGS
Complex Ruptures & Splay Faults UCERF3 more complex and super linkages Potential significant changes in fault strike Potential significant changes in fault rake UCERF3 Grand Inversion inhibits infeasible linkages Carlsbad Trend SJH SONGS OBT Northern Segment OBT Southern Segment
Focused Questions Summarize the tectonic setting What is the seismogenic thickness? Are you including deep ruptures in the upper mantle (~30 km)? Do you have splay faults or overlapping segments? Do you have complex multi-segment ruptures with different rakes/dips along strike? What is the largest magnitude in your sources (due to linked faults)? What is the range of dip angles (min & max) and faulting styles?
2010 PSHA Seismic Sources Fault Name Oceanside Blind Thrust (OBT) Newport Inglewood/Rose Canyon (NI/RC) Closest Distance (km) Maximum Magnitude (Mw) Fault Mechanism Basis 6 7.1 to 7.6 Reverse 2010 PSHA 8 6.8 to 7.5 Strike-slip USGS, 2009 Palos Verdes/Coronado Bank 32 7.6 to 8.0 Strike-slip UCERF2 Elsinore 38 7.0 to 8.2 Strike-slip UCERF2 San Diego Trough 46 7.0 Strike-slip USGS, 2009 San Jacinto 70 6.7 to 8.3 Strike-slip UCERF2 San Andreas 92 6.9 to 8.5 Strike-slip UCERF2 San Clemente 94 7.2 Strike-slip USGS, 2009 Remaining Sources > 100 6.4 to 7.4 Strike-slip & Reverse UCERF2
Complex Linkages: UCERF3 What about new UCERF3 super linkages? Will affect maximum magnitudes Under evaluation in SONGS SSC SSHAC Carlsbad Trend SJH SONGS OBT Northern Segment OBT Southern Segment
Future PSHA Seismic Sources? Fault Name Oceanside Blind Thrust (OBT) Newport Inglewood/Rose Canyon (NI/RC) Palos Verdes/Coronado Bank Closest Distance (km) Maximum Magnitude (Mw) Fault Mechanism Basis 6 7.1 to 7.6 (8+?) Reverse 2010 PSHA 8 6.8 to 7.5 (8+?) Strike-slip USGS, 2009 32 7.6 to 8.0 (8+?) Strike-slip UCERF2 Elsinore 38 7.0 to 8.2 (8+?) Strike-slip UCERF2 San Diego Trough 46 7.0 (to 7.8?) Strike-slip USGS, 2009 San Jacinto 70 6.7 to 8.3 (8+?) Strike-slip UCERF2 San Andreas 92 6.9 to 8.5 (8+?) Strike-slip UCERF2 San Clemente 94 7.2 (8+?) Strike-slip USGS, 2009 Remaining Sources > 100 6.4 to 7.4 (8+?) Strike-slip & Reverse UCERF2
Focused Questions Summarize the tectonic setting What is the seismogenic thickness? Are you including deep ruptures in the upper mantle (~30 km)? Do you have splay faults or overlapping segments? Do you have complex multi-segment ruptures with different rakes/dips along strike? What is the largest magnitude in your sources (due to linked faults)? What is the range of dip angles (min & max) and faulting styles?
Style of Faulting & Range of Dips STYLE RAKE min DIP max DIP STRIKE-SLIP Newport-Inglewood / Rose Canyon Simplified: RIGHT LATERAL 180 Actual? with convergence across restraints ~150? ~80 90 LOW-ANGLE REVERSE (THRUST) Oceanside Blind Thrust Simplified: THRUST 90 Actual? OBLIQUE? reverse right-lat? ~120? styles of deformation under evaluation in SONGS SSC SSHAC ~15 ~30
Focused Questions Summarize the tectonic setting What is the seismogenic thickness? Are you including deep ruptures in the upper mantle (~30 km)? Do you have splay faults or overlapping segments? Do you have complex multi-segment ruptures with different rakes/dips along strike? What is the largest magnitude in your sources (due to linked faults)? What is the range of dip angles (min & max) and faulting styles?
QUESTIONS/DISCUSSION
References Bird, P., 2003, An updated digital model of plate boundaries: Geochemistry Geophysics Geosystems, v. 4, no. 3, p. 1027, doi:10.1029/2001gc000252. Conrad, J., 2013, personal communication to P. Umhoefer. Conrad, J.E., Ryan, H.F., and Sliter, R.W., 2010, Tracing active faulting in the Inner Continental Borderland, Southern California, using new highresolution seismic reflection and bathymetric data [abstract]: Seismological Society of America 2010 Annual Meeting, Seismological Research Letters, v.81, no. 2, p. 347. GeoPentech, Inc., 2010, San Onofre Nuclear Generating Station Seismic Hazard Assessment Program: 2010 Seismic Hazard Analysis Report, prepared by GeoPentech, Inc. for Southern California Edison Co., 74 pp. plus appendices. Kent, G., 2012, personal communication to S. Duke. Nazareth, J.J., and Hauksson, E., 2004, The seismogenic thickness of the southern California crust: Bulletin of the Seismological Society of America, v. 94, no. 3, p. 940-960. Plesch, A., Shaw, J.H., Benson, C., et al., 2007, Community Fault Model (CFM) for southern California: Bulletin of the Seismological Society of America, v. 97, no. 6, p. 1793-1802. SCE, 2001, San Onofre Nuclear Generating Station Units 2 and 3 Seismic Hazard Study of Postulated Blind Thrust Faults, prepared by Geomatrix Consultants, GeoPentech, and Southern California Edison for the Nuclear Regulatory Commission, 26 December 2001, 165 pp. SCE, 1995, Seismic Hazard at San Onofre Nuclear Generating Station, prepared by Risk Engineering, Inc. for Southern California Edison Co., 2244 Walnut Grove Avenue, Rosemead, California 91770, 25 August 1995, 340 pp. Sorlien, C.C., Campbell, B.A., and Seeber, L., 2009b, Geometry, kinematics, and activity of a young mainland-dipping fold and thrust belt: Newport Beach to San Clemente, California, USDI/USGS Award No. 08HQGR0103 Final Technical Report, 25 pp. USGS, 2009, Quaternary fault and fold database for the United States, accessed 25 October 2010, from USGS website, [http//earthquakes.usgs.gov/regional/qfaults/]. USGS, 2008, Documentation for the 2008 update of the United States National Seismic Hazard Maps, prepared by Petersen, M. D., et al.: U.S. Geological Survey Open File Report 2008-1128. U.S.NRC, 2012, Title 10 of the Code of Federal Regulations, Part 100, Appendix A, available at [http://www.nrc.gov/reading-rm/doccollections/cfr/], accessed October 2012. WGCEP, 2012, in review, The Uniform California Earthquake Rupture Forecast, Version 3.1 (UCERF3.1), prepared by Working Group on California Earthquake Probabilities, accessed 5 February 2013 at [http://wgcep.org/ucerf3pt1]. WGCEP, 2008, The Uniform California Earthquake Rupture Forecast, Version 2 (UCERF2), prepared by 2007 Working Group on California Earthquake Probabilities: U.S. Geological Survey Open File Report 2007-1437 and California Geological Survey Special Report 203.