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

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

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: http://scec.usc.edu/scecpedia/Broadband_Platform.

Supported Broadband Platform Software Release

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

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.

Typical Broadband Platform Computational Stages Including Validation Stages

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

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 = 34.344 LON_TOP_CENTER = -118.515 HYPO_ALONG_STK = 6.0 HYPO_DOWN_DIP = 19.4 DT = 0.01 SEED = 3092096

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

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.

Validation Data Products Seismogram Comparison Goodness-of-fit

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

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.

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

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

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)

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

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

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

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)

Broadband Platform Development Support PGE, APS, SCE, PEER Support during 2012-2014 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

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

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

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

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

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