UCERF3 Scientific Review Panel

Tuesday, May 8, 2012 - Wednesday, May 9, 2012
Bill Ellsworth, Ned Field, and Tom Jordan
Davidson Conference Center, University of Southern California, Los Angeles

The preliminary UCERF3 Model will be formally reviewed by the Scientific Review Panel (SRP) on May 8-9, 2012. The meeting will include an overview of the preliminary model by Working Group, and a formal assessment by the SRP. The results of the review will be submitted to the California Earthquake Authority for their approval.

The primary focus of this meeting is a review the Grand Inversion methodology for defining long-term models, and to judge the viability of input elements.  Given this approach represents a major departure from past practice, plus the fact that interpreting results is also much more challenging, we will need the full meeting to focus on the inversion ingredients and results.  While the time-dependent components have been implemented in UCERF3, more time is needed to further evaluate their implications, and it does not make sense to do so until the long-term models are finalized (given that some tuning will be in order).  An exception is the Empirical model, which will be discussed at this meeting due to a tight coupling with earthquake-rate-model assumptions.

An explicit goal of this meeting is to establish consensus on a final set of logic-tree branches for the long-term model, the weighting of which will be determined by follow-up calculations and analyses.  Our final model, due to CEA by June 30th, will constitute a complete long-term model with proposed logic-tree branch weights.  This “final” model will then be reviewed by the SRP (and others) and revised accordingly.  The model will be also reviewed for use by the NSHMP at a public workshop in Oct. 2012. The extent to which the final model includes time dependence remains to be seen, but the WGCEP remains optimistic that it can deliver what was articulated in the project plan.

As described in the Preliminary Model Report, the Grand Inversion methodology is now up and running, and we can conduct runs for any and all of our presently defined logic tree branches.  The much bigger challenge is interpreting (and defending) the results of any one branch, mostly because we now have more than 200,000 ruptures defined in the fault system.  Indeed, the recent formal review raised several important questions with respect to the Grand Inversion.  To improve our understanding of the results, our recent efforts have focused on applying the methodology using UCERF2 ingredients, which avoids ambiguities of whether differences are caused by the new methodology or new data.  Considerable time will be spent presenting these results, with the goal of convincing the SRP that we can indeed construct a model that represents a clear improvement over UCERF2.

Consequently, the implications of many proposed logic-tree branches remain under-evaluated from the grand-inversion perspective, so their viability will therefore be discussed more from a theoretical and consistency-with-data perspective.  We acknowledge (and emphasize) that some branches that look good now may later be found incompatible with other inversion constraints (which itself reflects the power of the inversion methodology relative to previous approaches).

May 8 Title Presenter(s)
08:30 Continental Breakfast  
09:00 Introductory Remarks and Meeting Goals Tom Jordan
09:05 Summary of Review Process Bill Ellsworth
09:15 Overview of Long-Term Model Development
- Grand Inversion, off-fault seismicity, and logic-tree branches
Ned Field
09:30 Fault Models  
  - Addition of "fault zone" polygons Peter Powers
10:00 Deformation Models  
  - Has the block model been adequately reviewed Ray Weldon
  - Estimating off-fault strain rates Kaj Johnson
  - Which models represent viable branches? Tom Parsons
  - Possible revisions Tom Parson & Kaj Johnson
11:00 Seismicity Analysis Karen Felzer
  - Earthquake catalog  
  - Region magnitude frequency distribution estimates (including uncertainties for smaller regions)  
  - Smoothed seismicity models  
  - New empirical model  
11:30 Basic Implication of Deformation and Seismity Models Ned Field
  - In terms of inferring temporal rate changes, aseismicity, Mmax variations, and characteristic MFDs on faults  
12:00 Scaling Relationships Bruce Shaw
  - Summary of issues and options in light of reviews  
12:30 Lunch Break  
13:00 Grand Inversion Results Morgan Page
  - Treatment of creep examples, special cases like Parkfield and wall-to-wall SAF, laugh-test filter, simulated annealing convergence properties, detailed inversion comparisons with UCERF2, improbability constraint needed? Propagate data uncertainties via Monte Carlo sampling?  
13:30 Off-Fault Seismicity Peter Powers
14:00 Some Other Issues raised by Art Frankel Ned Field and Others
  - Missing data constraints: average paleo slip and correlated dates between paleo sites  
  - Average slip models ignore real along-strike variability  
  - Do aftershocks have a different spatial distribution (as smaller events that occur at ends of faults)?  
  - Mmax of off-fault seismicity?  
  - Inversion machinery is overly sophisticated  
14:30 Evaluating Building-Code Implications via RTGM Peter Powers
15:00 Statewide Portfolio Loss Analyses Ned Field & Keith Porter
15:30 Recap and Consensus Development of Viable Logic-Tree Branches Ned Field
16:00 Plan for Remainder of Project Ned Field
  - Time-Dependent Models (including OEF)  
  - Forthcoming Reports and Reviews  
  - Code evaluation?  
  - Publication (special issue of something?)  
16:30 - 18:00 Scientific Review Panel Executive Session SRP only
18:30 - 21:00 Group Dinner at University Club SRP, MOC, WGCEP only
May 9    
08:30 Continental Breakfast  
09:00 Feedback from SRP Bill Ellsworth
09:30 - 12:00 Round Table Discussion  
12:00 - 16:00 Scientific Review Panel Executive Session (including working lunch SRP only



Venue: The meeting will be held on the campus of the University of Southern California at the Davidson Conference Center Boardroom:

    Davidson Continuing Education Conference Center (DCC) - Boardroom
    University of Southern California
    3415 South Figueroa Street
    Los Angeles, CA 90089-0871
    (213) 740-5956

Lodging: We have a block of hotel rooms at the nearby Radisson Hotel for attendees who need overnight lodging.

    Radisson Hotel Los Angeles Midtown
    3540 South Figueroa Street
    Los Angeles, CA 90007
    (213) 748-4141

Transportation: The best airport to fly into is Los Angeles International Airport (LAX) or Bob Hope Airport in Burbank (BUR). Upon arrival at the airport, plan on taking a cab or shuttle service to the University of Southern California. You can take advantage of the 10% discount from Prime Time Shuttle when booking online directly through USC.

For the return flight, the best place to catch a cab/taxi is outside the Radisson Hotel (so you might want to leave your luggage at the hotel and not bring to the conference center).

Directions / Parking: Plan on parking at the Radisson Hotel if you need to park your car or rental car overnight. For those of you who need day parking only, reservations have been made at Parking Structure D (PSD). Enter at Entrance 4, and tell the parking attendant you are attending the “SCEC Meeting”, and you will be directed to the parking structure. See map for directions.

Meals: Breakfast, lunch, and refreshments will be served at DCC during the meeting.