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SCEC UGMS Committee Meeting

Conveners: C.B. Crouse and Tom Jordan
Dates: November 30, 2015 (10:00 - 15:00)
Location: SCEC Boardroom, USC, Los Angeles

SUMMARY: The SCEC Committee for Utilization of Ground Motion Simulations (or "UGMS Committee") is tasked to develop long-period response spectral acceleration maps for Los Angeles region for inclusion in NEHRP and ASCE 7 Seismic Provisions and in Los Angeles City Building Code. The maps would be based on 3-D numerical ground-motion simulations, and ground motions computed using latest empirical ground-motion prediction equations from the PEER NGA project. This project is coordinated with (1) the SCEC Ground Motion Simulation Validation Technical Activity Group (GMSV-TAG), (2) other SCEC projects, such as CyberShake and UCERF, and (3) the USGS national seismic hazard mapping project.

Presentation slides may be downloaded by clicking the links following the title. PLEASE NOTE: Files are the author’s property. They may contain unpublished or preliminary information and should only be used while viewing the talk.

Monday, November 30, 2015

10:00 - 10:15 Welcome, Attendee Introductions, and Agenda Review  
10:15 - 10:45 Meeting Agenda Overview and Review of Results from May 2015 Meeting (PDF, 3.1 MB) C.B. Crouse
10:45 - 11:15 Update on SCEC CyberShake Progress
- Hybrid Approach to Broadband Ground Motion Simulations (Graves and Pitarka, 2010, 2015)
(PDF, 3.9MB)
- Broadband CyberShake Calculations (PDF, 1.1MB)
- Discussion
Rob Graves / Scott Callaghan
11:15 - 11:45 Calculation of Risk-Targeted Maximum Considered Earthquake Response Spectra (MCER)
- Weighted Average of CyberShake and NGA-based MCER
- Discussion
Kevin Milner
11:45 - 12:00 Proposed approach to validating 3-D simulations before using them in engineering applications
(PDF, 2.7MB)
Norm Abrahamson
12:00 - 13:00 Lunch  
13:00 - 13:30 Updated Site Response Analysis (PDF, 2.7MB)
- Discussion
Domniki Asimaki
13:30 - 14:00 Technical Items for Resolution Before Finalizing Approach for MCER Calculations
- SCEC web MCER look-up tool for city of L.A. & other users (PDF, 227KB)
- Discussion
C.B. Crouse / Tom Jordan
14:00 - 14:30 Logistics and Schedule for Finalizing Long Period MCER Maps for L.A. Region in Short Term (e.g., Possible supplement to ASCE 7-16 for City of L.A.) and Long Term (2021 NEHRP & 2022 ASCE 7) C.B. Crouse
14:30 - 14:50 Future Work for CyberShake Tom Jordan
14:50 - 15:00 Results to be Presented and Tentative Dates for Next UGMS Meeting  
15:00 Adjourn  


UGMS Members Attending:
*Norm Abrahamson (PG&E)
*John Anderson (UNR)
Bob Bachman (R.E. Bachman)
*Jack Baker (Stanford)
C.B. Crouse (AECOM)
*Art Frankel (USGS)
Rob Graves (USGS)
John Hooper (MKA)
Marty Hudson (SEAOSC AMEC)
Tom Jordan (USC)
Nico Luco (USGS)
Paul Somerville (AECOM)
UGMS Members Absent:
Jacobo Bielak (Carnegie Mellon University)
Ron Hamburger (Simpson Gumpertz & Heger)
Curt Haselton (California State University, Chico)
Charles Kircher (Kircher & Associates)
Lew Marshall (SEAOSC AMEC)
Farzad Naeim (Farzad Naeim, Inc.)
Brad Aagaard (USGS)
Domniki Asimaki (Caltech)
Annemarie Baltay (USGS)
Scott Callaghan (USC)
David Gill (USC)
Christine Goulet (USC)
Tran Huynh (USC)
Ting Lin (Marquette)

Kevin Milner (USC)
Morgan Moschetti (USGS)
Ramin Motamed (University of Nevada, Reno)
Kim Olsen (SDSU)
Sanaz Rezaeian (USGS)
Andreas Skarlatoudis (AECOM)
Ricardo Taborda (Memphis)

*Remote Participants



A zip file with MCER results is available here.

Maximum Considered Earthquake Response (MCEr) maps for the Utilization of Ground Motion Simulations Committee, interpolated between 336 Study 15.4 CyberShake sites.

Period Probabilistic MCER Deterministic MCER Deterministic Lower Limit Combined MCER results
2 Second, RotD100
3 Second, RotD100
5 Second, RotD100
10 Second, RotD100


Period CyberShake Combined MCER GMPE Combined
Ratio (CyberShake/GMPE) Weight Average
2 Second, RotD100
3 Second, RotD100
5 Second, RotD100
10 Second, RotD100

Individual Site MCER Results

Site Deterministic MCER Combined MCER results Overall MCER results
Century City Plaza
Los Angeles Downtown
Lake Palmdale
San Bernardino Strong Motion
Santa Monica Civic Auditorium
710/90 Interchange
Whitter Narrows Golf Course

CyberShake/GMPE Combined Weights

The average spectrum (green lines in the above plots) represent a weighted average of CyberShake and the GMPEs. The weights are period dependent as shown below. Probabilistic results are averaged at the hazard curve level prior to calculation of the Risk Targeted Ground Motion value and deterministic results are averaged after deterministic calculation.