SCECCME Project Year 4 CyberShake Project

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SCEC/CME Project Year 4CyberShake Project

• Philip Maechling
• 22 June 2005

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CyberShake Project Create a Seismic Hazard
Analysis (SHA) Intensity Measure Relationship
(SHA) using 3D Synthetic Seismic Waveforms
(replacing the use of an attenuation
relationship).Calculate hazard curves using this
IMR
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CyberShake Background

• Goals of SCEC/CME are to utilize a more
  physics-based approach to SHA, and utilizing
  Pathway 2 as IMR has been discussed frequently.
• January 2005, SCEC/CME Group wrote a TeraGrid
  allocation request for Project to use Wave
  Propagation Simulations to calculate Hazard
  Curves for LA Basin.
• Proposal was accepted and awarded 145K SUs
  (TG-BCS050001N) on TeraGrid. Award good through
  March, 2006.
• Additional Service Units awarded from USC HPCC.

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Various IMR types (subclasses)

Attenuation Relationships
Gaussian dist. is assumed mean and std. from
various parameters
IMT, IML(s)
Multi-Site IMRs compute joint prob. of exceeding
IML(s) at multiple sites (e.g., Wesson
Perkins, 2002)
Site(s)
Rupture
Intensity-Measure Relationship List of Supported
IMTs List of Site-Related Ind. Params
Vector IMRs compute joint prob. of exceeding
multiple IMTs (Bazzurro Cornell, 2002)
Simulation IMRs exceed. prob. computed using a
suite of synthetic seismograms
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Example CyberShake Region (200km x 200km)
USC 34.05,-118.24 minLat31.889, minLon-120.60,
maxLat36.1858, maxLon-115.70
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Ruptures in ERF within 200KM of USC
43227 Ruptures in Frankel02 ERF with M 5.0 or
larger within 200km of USC
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SCEC/CME PSHA TeraGrid Project
TeraGrid Allocation Request Submitted to run 481
simulations to use AWM as IMR. Incorporates
Pathway 1, Pathway 2, Workflow tools, Data
Management
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Ruptures in ERF within 200KM of USC

• In order to simulate the number of required
  Ruptures, a reciprocity-based approach has been
  selected.
• Reciprocity approach supports many ruptures
• Because significant calculations are required for
  each site, limitation becomes number of sites.
• Output will be hazard curves. If enough sites are
  run, a hazard map will be created.

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Example Hazard Curve
Site USC ERF Frankel-02 IMR Field IMT Peak
Velocity Time Period 50 Years
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Five Items in Hazard Curve to be Used in
CyberShake

• ERF Frankel-02
• IMR Reciprocity-based waveforms (horizontals
  only)
• Sites USC (Basin), Pasadena (Rock), TBD
• IMT Spectral Acceleration at 3 Seconds
• (calculated by attenuation relationships
  including Abrahamson, A Silva, Campbell,
  Field, Sadigh)
• Time Period 50 years

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All Calculations are Repeated Per Site

• Unit of Planning for CyberShake is Site
• We run a series of calculations for each site.
• Once all site calculations are completed, we can
  produce a hazard curve for that site.
• First site is USC (Basin) Second Site is PAS
  (Rock)
• Additional site selection is TBD.

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Elements of the CyberShake Computation
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Elements of the CyberShake Computation
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CyberShake Strain Green Tensor AWM

• Large (TeraShake Scale) forward calculations for
  each site.
• SHA typically ignore rupture gt 200km from site,
  so this is used as cutoff distance.
• 20km buffer distance is used around edges of
  volume to reduce edge effects
• 65km depth to support frequencies of interest
• Volume is 440km x 440km x 65km at 200m spacing
• 1.573 Billion mesh pts
• Simulation time 180 seconds
• Volumetric Data Saved for 2 horizontal
  simulations
• Estimated Storage per site is 11.5 TB (9.0 data
  2.5 checkpoint files)

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CyberShake Rupture Descriptions

• Rupture description must be exchanged between ERF
  and Pathway 2 AWM codes (Strain Green Tensor
  Codes).
• Rupture description will be generated with a
  program (RuptureWithSlipTimeFunctionGenerator)
  that inputs ERF description and output R.Graves
  Rupture Description (with variations)
• Rupture variations are TBD. Maybe strike ,
  strike -, dip , dip 1.
• Pseudo-dynamic code may be integrated to
  investigate its impact on hazard curves.

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CyberShake Computational Elements
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CyberShake Seismogram Extraction

• Requires calculation of 100,000 seismogram for
  each site.
• Estimate Rupture Variations scale by magnitude
• Mw 5.0 x 1 20,450
• Mw 6.0 x 10 216,990
• Mw 7.0 x 100 106,900
• Mw 8.0 x 1000 9,000
• ------------------
• 353,340 Ruptures
• x 2 components
• Current estimated number of seismogram files per
  site is 43,000 (due to combining components and
  variations into single file per rupture).

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CyberShake Workflow Tools

• SCEC/CME Grid-based scientific workflow system
  required to work at this scale.
• Access to distributed computing resources
• Large scale file management
• High performance and high throughput computing.

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Examples Hazard Map Region (50km x 50km at 2km
grid spacing 625 sites)
OpenSHA SA 1.0 Frankel 2002 ERF and Sadigh with
10 POE in 50 years.
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CyberShake Issues

• Need exchange of rupture between ERF and STG
  codes. (Rupture format, Rupture Variation
  Generator)
• Which codes to use (Zhao modification of Olsen
  AWM, Graves)
• What IM Types can we calculate (is SA 3.0s only
  IMT useful)
• Which results are worth saving (Green Tensors,
  Seismograms, curves)
• Site selection strategy
• Need for additional SUs
• Integration of all computation elements into
  workflow.
• How to present non-visual results.