Validation of the Wasatch Front Community Velocity Model Preliminary Results Kim Olsen Daniel Roten

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Validation of the Wasatch Front Community
Velocity Model - Preliminary ResultsKim
OlsenDaniel RotenHarold MagistraleSDSUJim
PechmannU of UUGS Salt Lake CityFeb 12 2008
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Event
Event 14179736 (M 5.1) Vsmin500 m/s, f lt
1 Hz
Southern Californiamodel dimensions 600 km x
300 km x 80 km (CMU etree) Chen et al
2008 dx200m, Vsmin500 m/s, fmax 0.5
HzSource point source
Event 14179736 (M 5.1) f lt 1 Hz
0-1Hz
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• Validation Events
• ML 3.32 Magna 010708, depth 11.6 km
• MW 3.66 Tremonton 070901, depth 9 km
• ML 3.30 Lehi 010524, depth 8.9 km

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First Q model (Olsen et al., 2003) Qs0.02Vs for
Vs lt 1500 m/s Qs0.1Vs for Vs gt 1500
m/s Qp1.5Qs Revised Q model (Brocher,
2006) Qs-16104.13Vs-25.225Vs28.2184Vs3 Qs13
for Vslt0.3 km/s Qp2Qs
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Q versus no Q
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ML3.3 Lehi Event
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ML3.3 Lehi 0.5-1.0Hz The better fits
50 s
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ML3.3 Lehi 0.5-1.0Hz The not-so-great fits
50 s
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50 s
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50 s
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ML 3.9 Tremonton Event
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0.4-0.7 Hz
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0.5-1.0 Hz
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• Summary of preliminary CVM validation

• 3 validation events show general basin
  amplification fit
• Selected stations show puzzling underprediction
  
• Some refinement of WFCVM needed based on
  validation
• Need further refinement of Q (larger Q?)
• Release WFCVM for ground motion modeling
  (when?)