Nevada Great Basin Community Velocity Model Workshop

1
Nevada Great Basin Community Velocity Model
Workshop
Welcome from All of Us at the Nevada
Seismological Lab Convenor J. Louie (cell
775-229-3835) Arrangements Lori McClelland
(mcclella_at_unr.edu) Generously Funded by the USGS
NEHRP-NIW External Grants Program, Mark Petersen,
Regional Coordinator
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Objectives

• Organize a Nevada community seismic-velocity
  modeling effort for the western Great Basin
• Goal is predicting earthquake ground motions in
  urban areas and other sensitive sites.
• The CVM will
• address seismic velocities at the crustal, basin,
  and geotechnical scales and
• contribute directly toward an overall Great Basin
  Community Velocity Model.

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Objectives (cont.)

• Will hear from experts who have constructed other
  CVMs
• Assess what CVM features most affect predicted
  ground motions
• Prioritize our needs for geological and velocity
  data
• We are not assessing sources

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Products

• Develop at the workshop succinct statement of
  research and data needs that can immediately be
  included in the next USGS NEHRP-NIW RFP.
• Louie will write (with help) a white paper by
  March 2008.
• Available at the www.seismo.unr.edu/gbcvm website
  to those writing NEHRP proposals.

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Last Years Nevada Priorities

• Improve and validate 3D velocity models needed
  for waveform modeling of the effects of basin-
  and near-surface-geology
• For Reno-Carson City, and Las Vegas
• Using a variety of techniques including Vs30,
  tomography, inversion of seismograms,
  correlations with incorporation of geology, etc.
• Incorporate results into the Community Velocity
  Model

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Last Years Nevada Priorities

• Test the sensitivity of shaking to velocity
  structure at various scales
• As a guide to identifying those parts of the
  velocity model most in need of further study
• Use ANSS data in Reno/Carson, and Las Vegas
• To find empirical site response, validate
  predictions of 3D velocity models, and improve
  ground motion prediction approaches.
• Prepare scenario ground motion models based on
  waveform modeling
• For earthquakes on major faults affecting
  Reno/Carson and Las Vegas.

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Next Years Nevada Priorities

• Develop a Western Basin Range CVM
• To cover the entire region with existing
  geological and geophysical information, plus
  embedded details for the Reno-Carson City Urban
  Corridor (including Tahoe), and the Las Vegas
  Metro area (including Pahrump Valley).
• Validate the CVM during its development by
  generating synthetics from the 3-d model for
  recordings of moderate earthquakes and
  explosions. Revise the model to incorporate
  validation results.

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Next Years Nevada Priorities

• Develop new data for incorporation into the
  Western Basin Range CVM
• Western Basin Range Region
• Develop a regional map of shallow shear
  velocities and densities from existing
  measurements for inclusion in the CVM, and for
  use in ShakeMap.
• Las Vegas Metro Area (including Pahrump Valley)
• Construct a model for the structure of the edges
  of the Pahrump basin, consistent with fault
  models, for inclusion in the CVM.
• Obtain generalized depths of important impedance
  contrasts in Las Vegas Valley for inclusion in
  the CVM.
• Reno/Carson City Urban Corridor (including Tahoe)
• Construct cross sections of the significant
  basins, consistent with available geological and
  geophysical data sets, for inclusion in the CVM.
• Collect shallow Vs measurements at
  uncharacterized ANSS sites, and on geologic units
  not well characterized.
• Compile and develop a detailed shallow
  shear-velocity model for the Urban Corridor using
  existing geological and geophysical data.
• Obtain generalized depths of important impedance
  contrasts in the Urban Corridor.

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Next Years Nevada Priorities

• Delete Test the sensitivity of shaking to
  velocity structure at various scales
• As a guide to identifying those parts of the
  velocity model most in need of further study
• Keep Use ANSS data in Reno/Carson, and Las Vegas
• To find empirical site response, validate
  predictions of 3D velocity models, and improve
  ground motion prediction approaches.
• Update Prepare scenario ground motion models
  based on waveform modeling with the Western Basin
  Range CVM.
• For earthquakes on major faults affecting
  Reno/Carson and Las Vegas.

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Schedule- Monday AM

• 800 Louie Introduction, thanks, and workshop
  objectives
• Status of CVM efforts in Nevada
• 820 Louie Crustal thickness in the northern
  Sierra and northern Nevada
• 840 Anderson Need for accurate velocity models
  in NV network seismol
• 900 von Seggern Joint seismic tomography/relocati
  on, Reno-Carson
• 920 Rodgers 3-d models of the southern Great
  Basin, and shaking in LV
• 1020 Luke Shear wave velocity profiling in Las
  Vegas valley
• 1040 Pancha Need for an accurate Reno velocity
  model
• 1100 Henry Three-dimensional geologic complexity
  of the Truckee Meadows basin from geologic
  mapping
• 1120 Liberty Geophysical characterization of
  the Hot Creek Valley, central Nevada
• 1140 Moschetti Application of empirical Green's
  functions in the construction and validation of
  the Great Basin CVM

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Schedule- Monday PM

• 130 Louie The MA-CME modeling environment and
  initial scenario ground-motion computations for
  Reno and Las Vegas
• USGS objectives, funding, internal external
  projects, and collaborations
• 150 Odum NEHRP-NIW priorities, funding,
  internal projects and the Nevada CVM
• Status and results of Utah CVM
• 210 Magistrale The Wasatch Front CVM
• Other CVM efforts- their advice
• 240 Sydnor Applications of shear-wave velocity
  to the Building Code
• 300-340 Break for coffee and discussion
• 340 Wills Preparing maps of Vs30 based on
  geologic maps
• 410 Rodgers The 1906 modeling effort, and
  lessons learned
• 440 Louie for Keller Open Earth Framework
  Building 3-d models via integration of geological
  and geophysical data
• 450 Louie CVM efforts in Wellington, New Zealand
• 500 Questions, wrap-up, charge for Tuesday
  discussions

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Schedule- Tuesday

• 800-940 Discussion- What results do we need in
  a Nevada CVM for ground-motion prediction?
• We will have an Official Version. Datasets are
  included if difference is significant when tested
  by CVM group.
• Regional
• 1. P-wave tomography- start w/ Hearn- add
  Preston, Biasi, S. NV, gravity (Jachens)
• 1. Exists crustal Vs model from TA-EGF (Morgan)
• 1. Basin geometry
• What is the database- collaborations?
  Earthvision, MA-CME (some devel. Needed),
  Magistrale code- merging/smoothing?
• 1. Geotech layer
• 2. Geotech Wills, scope out- ShakeMap, MX Missile
  files
• 2. Catalog of fault dips (add to Qfaults?),
  Geology (structure and stratigraphy) of basin
  edges- collaboration with DOE-geothermal?
• 2. Rework of Jachens regional basin gravity with
  better fault dips
• Model uncertainties- subject for NSF, DOE
  proposals? How to honor needs of ultimate
  customers?

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Schedule- Tuesday

• 800-940 Discussion- What results do we need in
  a Nevada CVM for ground-motion prediction?
• Reno/Carson City Urban Corridor
• 1. 3-d Geology of basin floor and edges- fault
  models-gt define cross section (1. Carson Range
  fault system simple geometry model 2. Basin
  east-side faults)
• 1. assemble existing sections through Reno and
  Carson Val. (Cashman, Henry)
• 1. Abbott basin model- Reno, Eagle Val.- products
  available from Washoe Co.
• 2. Oppliger Carson Val. gravity database modeling
• 2. Carson Range fault system model
  development-USGS collab
• 1. Tahoe Basin model, Karlin, UCSD
• 2. Remodeling of reno basin, including new wells,
  Washoe Co. gravity
• 1. Geotech layer- Louie, Pancha
• 1. Vs at Carson-Valley ANSS, unmeasured geologic
  units (by USGS?), Geotech data correlation with
  Geology
• 1. P-S tomography from Preston
• 1. R1, R2, R3 from reflection by USGS?
  Stephenson-UNLV collab?
• 1. Deep basin (gt100 m) Vs from UNR (funded FY08)
• 2. Soil nonlinearity- assembly plus new models

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Schedule- Tuesday

• Las Vegas Metro Area (incl. Pahrump Val.)
• 1. Geology of Pahrump basin edges- fault models
• 1. Langenheim basin model- LVV.
• 2. Roach Val., Coyote Springs basin models
• 2. Pahrump basin model from D. Donovan, Hoffard?
• 1. Geotech layer- Louie, Luke2. Nellis
  assessments (collab w/ Air Force), Geotech
  correlation with Geology from UNLV? Vs at ANSS
  sites (w/ USGS?)
• 1. Hearn, Moschetti P-S tomography- too few
  stations for LVV-Pahrump detail model
• 1. R1, R2, R3, reflection, refraction LVV
  (Snelson), Pahrump from D. Donovan, Hoffard
  theses?
• 1. Deep basin (gt100 m) Vs from UNLV 2. Vetted
  improved, interstation phase vel, EGF, Abbotts
  Pahrump array- collaboration
• Collaborations- New seismic stations for
  tomography and site response
• 2. Soil nonlinearity- assembly plus new models

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Schedule- Tuesday

• Who will use the CVM, and how?
• Simulators, validators
• Who does model assembly? Framework?
• Eastern California, Nevada, Utah CVM Western
  Basin Range CVM
• MA-CME adopts Magistrale subroutines
• Someone assembles refs and sections, rules and
  1-d profiles, geotech layers, DOE YM info?
• Who does synthetics and validation? Code?
• Collaborative project with Olsen?

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Airport times

• Monastero- 300- Luke
• Vincent 200- Moschetti
• Rodgers 100-
• Norris 400- Magistrale

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Schedule- Tuesday

• 1020-1200 Discussion-
• How do we obtain the necessary data and results?
• What methods are cost-effective enough to be
  funded?
• What collaborations are needed?
• Need a document to take to potential funders
• White paper to USGS, report on meeting to NESC
  Feb
• Version, vetted by NESC May, for forums in Reno,
  LV, including (what will they get out of it)
• USGS volcano, groundwater wat res
• Utilities SPPCo, Nevada Power, TMWA, SNWS, SNWA
• FEMA (security of Dam, CA power trans), NV-DEM,
  ACE, USBurRec, Army (commander of Hawthorne),
  Navy, Air Force (LVV-Nellis base engineer
  colonel- mission integrity force readiness)
• Gas pipelines, oil pipelines
• Builders NNBA, WNBA, SNBA- AEG regions
• NRC
• NDOT
• DOE- YMP, NNSA, GMSEC- NSO
• AEG, ASCE, SEASoN, Reno Las Vegas Chapt. AIA?
• NV public works board, fire marshall
• Multi-hazard efforts, emergency managers

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Schedule- Tuesday

• 1200-300 Working lunch and Discussion-
• Write and order Nevada CVM priorities for NEHRP
  RFP
• 300 Adjourn