Difference between revisions of "Broadband CyberShake Validation"

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=== Sites ===
 
=== Sites ===
  
The BBP validation event for Chino Hills has 40 stations.  A KML file with the stations is available [[File:chino_hills_stations.kml|here]].
+
The BBP validation event for Chino Hills has 40 stations.  A KML file with the stations is available [[:File:chino_hills_stations.kml|here]].
  
 
=== BBP ===
 
=== BBP ===

Revision as of 20:04, 16 May 2022

This page follows on CyberShake BBP Verification, moving from 1D comparisons to 3D CyberShake comparisons with both the BBP and observations.

Northridge

1D BBP comparisons

We calculated 64 realizations for Northridge for these 38 stations.

Some of the differences between the 1D BBP and 3D CyberShake results can be attributed to differences in site response, which is calculated based on the reference velocity ('vref') and the vs30 of the site. A spreadsheet with vref and Vs30 for both the BBP and CyberShake is available File:BBP v CyberShake Northridge vs30.xls

V1 (2/14/22)

Initially, we used vref=500 for both the high-frequency and low-frequency site response. However, this is incorrect; vref for the low-frequency should vary depending on the properties of the 3D velocity mesh.

V2 (2/25/22)

We continued to use vref=500 for the high-frequency site response. For the low-frequency site response, we are now using the same vref we used in Study 15.12:

vref_LF_eff = Vs30 * [ VsD5H / Vs5H ]

Vs30 = 30 / Sum (1/(Vs sampled from [0.5,29.5] in 1 meter increments))

H = grid spacing

Vs5H = travel time averaged Vs, computed from the CVM in 1 meter increments down to a depth of 5*H

VsD5H = discrete travel time averaged Vs computed from 3D velocity mesh used in the SGT calculation over the upper 5 grid points

So, for H=100m Vs5H would be:

Vs500 = 500 / ( Sum ( 1 / Vs sampled from [0.5,499.5] in 1 meter increments ))

And then VsD5H is given by:

VsD500 = 5/{ 0.5/Vs(Z=0m) + 1/Vs(Z=100m) + 1/Vs(Z=200m) + 1/Vs(Z=300m) + 1/Vs(Z=400m) + 0.5/Vs(Z=500m) }

Below are the ts_process plots for a subset of 10 stations, comparing the 3D CyberShake with 1D BBP results.

Site TS Process plot
SCE
Ts process SCE src0 2 25.png
SYL
Ts process SYL src0 2 25.png
LDM
Ts process LDM src0 2 25.png
PAC
Ts process PAC src0 2 25.png
PKC
Ts process PKC src0 2 25.png
SPV
Ts process SPV src0 2 25.png
WON
Ts process WON src0 2 25.png
KAT
Ts process KAT src0 2 25.png
RO3
Ts process RO3 src0 2 25.png
ANA
Ts process ANA src0 2 25.png

V3 (3/2/22)

Next, we recalculated the CyberShake results for 10 sites, using the BBP vs30 values for both the low-frequency and high-frequency elements. Note that the vref low-frequency value for CyberShake is still being derived from the velocity model.

Site TS Process plot
SCE
Ts process SCE src0 3 2.png
SYL
Ts process SYL src0 3 2.png
LDM
Ts process LDM src0 3 2.png
PAC
Ts process PAC src0 3 2.png
PKC
Ts process PKC src0 3 2.png
SPV
Ts process SPV src0 3 2.png
WON
Ts process WON src0 3 2.png
KAT
Ts process KAT src0 3 2.png
RO3
Ts process RO3 src0 3 2.png
ANA
Ts process ANA src0 3 2.png


Observational Comparisons

We calculated goodness-of-fit results for both Broadband CyberShake and the BBP against observations for Northridge, using the 64 realizations and 38 stations.

TS process plots comparing the 3 results are available here: v1 ts process plots.

Broadband Platform

Overall GoF GoF, best realization (#7) GoF, worse realization (#15)
BBP-GoF-NR-combined.png
BBP-GoF-NR-real7.png
BBP-GoF-NR-real15.png

CyberShake v4_8

Overall GoF GoF, best realization (#53) GoF, worse realization (#54)
CyberShake-GoF-NR-4 8 combined.png
CyberShake-GoF-NR-4 8 real53.png
CyberShake-GoF-NR-4 8 real54.png

Broadband Platform, updated frequency bands

We realized that our GoF comparisons were run using hard-coded frequency bands of [0.05, 50] Hz. This was correct when doing CS-to-BBP comparisons, but not correct when using observations. We updated the frequency bands and reran the GoF.

Overall GoF GoF, best BBP realization (#47) GoF, worst BBP realization (#25) GoF, best CS realization (#40) GoF, worst CS realization (#37)
BBP-freqbands-GoF-NR-combined.png
BBP-freqbands-GoF-NR-real47.png
BBP-freqbands-GoF-NR-real25.png
BBP-freqbands-GoF-NR-real40.png
BBP-freqbands-GoF-NR-real37.png


CyberShake v4_8, updated frequency bands

As above, reran the GoF.

Overall GoF GoF, best CS realization (#40) GoF, worst CS realization (#37) GoF, best BBP realization (#47) GoF, worst BBP realization (#25)
CyberShake-GoF-NR-4 8 freqbands combined.png
CyberShake-GoF-NR-4 8 freqbands real40.png
CyberShake-GoF-NR-4 8 freqbands real37.png
CyberShake-GoF-NR-4 8 freqbands real47.png
CyberShake-GoF-NR-4 8 freqbands real25.png


CyberShake v4_28, BBP Vs30

We recalculated the CyberShake GoF results, using the BBP Vs30 values.

Overall GoF GoF, best CS realization (#40) GoF, worst CS realization (#51) GoF, best BBP realization (#47) GoF, worst BBP realization (#25)
CyberShake-GoF-NR-4 28 combined.png
CyberShake-GoF-NR-4 28 real40.png
CyberShake-GoF-NR-4 28 real51.png
CyberShake-GoF-NR-4 28 real47.png
CyberShake-GoF-NR-4 28 real25.png

BBP, FAS

CyberShake v4_7, FAS

CyberShake-GoF-NR-4 7 FAS.png

Chino Hills

For our second event, we selected Chino Hills.

Sites

The BBP validation event for Chino Hills has 40 stations. A KML file with the stations is available here.

BBP

Overall GoF GoF, best realization (#24) GoF, worst realization (#35) GoF, worst CS realization (#34)
BBP-GoF-CH-combined.png
BBP-GoF-CH-real24.png
BBP-GoF-CH-real35.png
BBP-GoF-CH-real34.png

CyberShake

Overall GoF GoF, best realization (#24) GoF, worst realization (#34) GoF, worst BBP realization (#35)
CS-GoF-CH-combined.png
CS-GoF-CH-real24.png
CS-GoF-CH-real34.png
CS-GoF-CH-real35.png