1. The SCEC Broadband Platform: Computational Infrastructure For Transparent And Reproducible Ground Motion Simulation
Philip J. Maechling [1],
Fabio Silva [1], Scott Callaghan [1], Thomas H. Jordan [1]
[1] Southern California Earthquake Center
Session T19: Introduction To Engineering Uses Of Physics-Based Ground Motion Simulations
10NCEE: 10th U.S. National Conference on Earthquake Engineering
July 22, 2014 Anchorage Alaska

2. Agenda Overview of the Broadband Platform
Basic Capabilities of the Broadband Platform
Establish Support for Engineering Validation Processes
From Research Software To Community Software
Conclusions

3. What Is the Broadband Platform?
The Broadband Platform (BBP) is an open-source software distribution that:
Calculates earthquake ground motions at frequencies above 10Hz across regional distances.
Contains software tools for comparing simulation results against GMPEs and observed ground motion recordings.
Can run large numbers of ground motion simulations and manage the simulation results.
Available for download at:

4. Supported Broadband Platform Software Release

5. Agenda Overview of the Broadband Platform
Basic Capabilities of the Broadband Platform
Establish Support for Engineering Validation Processes
From Research Software To Community Software
Conclusions

6. Broadband Platform Usage Modes
SCEC Broadband Platform Capabilities:
Use Case 1: Calculate Historical Seismograms
User selects a validation event and the platform calculates broadband synthetic seismograms at selected locations and compares synthetic seismograms to observed data.
Use Case 2: Calculate Scenario Seismograms
- User defines parameters for a scenario earthquake, selects modules to use, and calculates broadband seismograms for the event.

7. Typical Broadband Platform Computational Stages Including Validation Stages

8. Broadband Platform Supports Multiple Ground Motion Simulation Methods
BBP simulations can use one or more of the currently integrated ground motion simulation methods
Graves & Pitarka – Rob Graves, Arben Pitraka
SDSU – Kim Olsen, Rumi Takedatsu
UCSB – Ralph Archuleta and Jorge Crempien
ExSIM (UWO) – Gail Atkinson, Karen Assatourians
Composite Source Model (UNR) – John Anderson

9. Common BBP Simulation Inputs
Simple Source Description
Station List
Velocity Model 1D Profile
MAGNITUDE = 6.67
FAULT_LENGTH = 20.01
DLEN = 0.2
FAULT_WIDTH = 25.01
DWID = 0.2
DEPTH_TO_TOP = 5.0
STRIKE = 122
RAKE = 90
DIP = 40
LAT_TOP_CENTER =
LON_TOP_CENTER =
HYPO_ALONG_STK = 6.0
HYPO_DOWN_DIP = 19.4
DT = 0.01
SEED =

10. Computational Stages Implemented Differently by Alternative Methods
Common
Inputs
GenSlip
JbSim
Hfsim
 GP
Common
post-processing methods
Example: RotD50
GenSlip
JbSim
BBToolbox
 SDSU
GP Method
UCrmg
Syn1D
 UCSB
ExSIM
 EXSIM
Simula
 CSM
Green

11. Broadband Platform Usage Modes
SCEC Broadband Platform Capabilities:
Use Case 1: Calculate Historical Seismograms
User selects a validation event and the platform calculates broadband synthetic seismograms at selected locations and compares synthetic seismograms to observed data.
Use Case 2: Calculate Scenario Seismograms
- User defines parameters for a scenario earthquake, selects modules to use, and calculates broadband seismograms for the event.

12. Validation Data Products Seismogram Comparison
Goodness-of-fit

13. Comparison Data Products
Goodness-of-fit
Spectral response comparison
Seismogram comparison
MAP based Goodness-of-fit

14. Broadband Platform Usage Modes
SCEC Broadband Platform Capabilities:
Use Case 1: Calculate Historical Seismograms
User selects a validation event and the platform calculates broadband synthetic seismograms at selected locations and compares synthetic seismograms to observed data.
Use Case 2: Calculate Scenario Seismograms
- User defines parameters for a scenario earthquake, selects modules to use, and calculates broadband seismograms for the event.

15. WAVEFORM COMPARISON: GP, SDSU, & ExSIM
STATION ON HANGING-WALL SIDE:
RX = 10.5 km, RJB = 6.5 km, RRUP = 9.2 km

17. Agenda Overview of the Broadband Platform
Basic Capabilities of the Broadband Platform
Establish Support for Engineering Validation Processes
From Research Software To Community Software
Conclusions

18. Large collaborative validation of the SCEC Broadband platform
SCEC is collaborating with SWUS and PEER to improve the usefulness of the BBP software
Broadband improvements motivated by need of seismic hazard projects to supplement the recorded datasets
PEER NGA-West projects
South-Western U.S. utilities (SWUS)
PEER NGA-East project (new CEUS hazard model)

19. Large collaborative validation of the SCEC Broadband platform
Broadband platform improvements
Integration and testing of 5 simulation methods
Multiple pre and post-processing tools
Validation against
Western US, Japan, Eastern North American past earthquake scenarios
Multiple environments and tectonic regions
Cover different fault mechanisms and geometries
Span wide magnitude range (Mw 4.64 to 7.62)
~40 stations per event (at least 17 scenarios)
Western U.S. empirical models
Simulation ensemble runs
Include multiple source realizations for each method
Summarized in large number of plots for evaluation

20. Description of What is Needed to Support Engineering Validation Process
• Demonstrate that the simulations work
Comparison with ground motions from past earthquakes (part A)
Check of the method to simulate future earthquakes (Part B)
• Repeatable results (stable versions)
Move from researcher codes (frequent tinkering) to fixed versions
• Usable by someone other than author of method
Clear guidelines on how to implement the methods
IT Support for running methods
• Reviewable
Peer review by someone other than author of code needs to be possible
• Reasonable costs

21. Agenda Overview of the Broadband Platform
Basic Capabilities of the Broadband Platform
Establish Support for Engineering Validation Processes
From Research Software To Community Software
Conclusions

22. Broadband Platform Development History
2006 – Scripted and Pegasus Version Developed
2008 – Python Version Developed (First Hanging Wall Problem)
2010 – First Supported Software Release of Platform
2011 – Second Version Released (v11.2.2) (Second Hanging Wall Problem)
2013 – SWUS Release of Broadband Platform (v13.9.1)
2014 – NGA-E Release of Broadband Platform (v14.3.0)

23. Broadband Platform Development Support
PGE, APS, SCE, PEER Support during
Add new validation event data sets
Add new validation processing and GOF
Run large scale simulations
Add new modules
Improve scalability by prepare code to run on Cluster
SCEC NSF-SI2 project funding over three years.
Prepare open-source scientific software distribution
Use modern software engineering development techniques
Increase scalability of scientific software

24. SCEC Software Engineering Improvements to Research Codes
Source code Version Control : Subversion
Selected Coding Standards: Python PEP8 Style Guide
Use of Code Checker: pylint
Simplified Codebase: Removed unneeded features
Reduced required compilers: Now Gnu and Intel.
Documentation: Online Installation and User Guide
Open-Source License: Apache 2
Validation: Scientific Review of Results on Standard Problems by SWUS and NGA-E
Public Software Release: Open-source distributions provide transparency Sept 2013, March 2014

25. SCEC Performs Forward Modeling: Ensembles of Earthquake Scenarios
Implement software tools to support large suites of simulations for scenario earthquakes
Configured the BBP to run on SCEC server and on USC Cluster, so that it is capable of running large ensembles of simulations.
Scenario runs are conducted by person other than developer of modules

26. Agenda Overview of the Broadband Platform
Basic Capabilities of the Broadband Platform
Establish Support for Engineering Validation Processes
From Research Software To Community Software
Conclusions

27. SCEC’s Broadband Platform software sustainability strategies
Keep the software development costs at a modest level (~2-3 FTE).
Integrate the best available scientific modules into the software.
Regularly release improved versions of Broadband as open-source software.
Release the software under a license (Apache 2) that is acceptable to commercial companies, and state and Federal agencies.
Continue the ongoing group verification and validation exercises to build user confidence in the software.
Implement software features and enhancements guided by a users needs and priorities

28. Thank you. The BBP Software is available for download at: http://scec