th Discussion Decision time for NSHMP amp possible predicaments Suggested steps forward Review logic tree options amp evaluation criteria Decision time for NSHMP Present Situation Possibilities ID: 284542
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Slide1
Oct 18th Discussion …
Decision time for NSHMP (& possible predicaments)
Suggested steps forward
Review logic tree options
& evaluation criteriaSlide2
Decision time for NSHMP
Present Situation Possibilities
UCERF3 is reviewed in short order and everyone is happy with methodology and results
UCERF3 is deemed technically flawed and not fixable in time for 2014 NSHM.Given complexity, there is not enough time for adequate review & vetting of UCERF3 for NSHMUCERF3 is found to be technically sound (with inevitable adjustments), but mean hazard changes are up to factors of 10 in many areas (and only understood to some level of specificity)
Probability10%20%30%50%
NSHMP options here?...Slide3
Decision time for NSHMP
NSHMP Options if there is no UCERF3:
Do not update CA ERF for 2014 NSHMs
Only update non fault-based sources (with alternative regional rates and spatial PDFs)Do (b) and add some of the new faults as type-B sources (bulge will increase) using geologic slip rates
Update everything including Type-A faults in a “UCERF2-like” way Issues:
What exactly is “UCERF2-like”?
Who would do this (WGCEP is already near burnout & would be demoralized)?This could take as long as fixing UCERF3Given La Quila, would anyone sign off on amodel
that lacks multi-fault ruptures?Slide4
Decision time for NSHMP
Present Situation Possibilities
UCERF3 is reviewed in short order and everyone is happy with methodology and results
UCERF3 is deemed technically flawed and not fixable in time for 2014 NSHM.Given complexity, there is not enough time for adequate review & vetting of UCERF3 for NSHMUCERF3 is found to be technically sound (with inevitable adjustments), but mean hazard changes are up to factors of 10
in many areas (and only understood to some level of specificity)Probability10%20%30%
50%
Given:
El Mayor-
Cucapah
(
M
max
)
Darfield
-
Christchurch (
Mmax & triggering)Tahoku (segmentation)M8.6 Sumatra (“weird one”)does anyone believe we know mean hazard within 10%?Are we reluctant to put these out because it implies we’ve misled user communities (or didn’t push the epistemic uncertainties hard enough)?Is looking at hazard implications before finalizing weights cheating?Slide5
Oct 18th Discussion …
Decision time for NSHMP (& possible predicaments)
Suggested steps forward
Review logic tree options & evaluation criteriaSlide6
The WGCEP Path Forward(the only one, in my opinion
)
Wrap it up
(finish and publish ASAP) in part, to satisfy contractual obligation to CEALet others decide what to use in 2014 NSHMs e.g., some weighted average of old and new hazard curves at each grid nodeSlide7
The WGCEP Path Forward(the only one, in my opinion
)
Specific steps:
Get feedback here on final branches (& weights)Decide how to handle convergence and equation set weightsDecide on any a posteriori weighting scheme (what to add to Morgan’s data-fits table?)Finalize calculations & document for review (by Nov 1st if all goes well?
)Activate review (hands on, aggressive, back and forth in terms of answering questions); how long will this take? Finish by year end?Finalize & publish in 2013Slide8
Oct 18th Discussion …
Decision time for NSHMP (& possible predicaments)
Suggested steps forward
Review logic tree options & evaluation criteriaSlide9
Proposed Logic-Tree Branches:Slide10
Proposed Logic-Tree Branches:
Two Fault Models
S
ame number as in UCERF2
Weighted equallySlide11
Proposed Logic-Tree Branches:
Four Deformation Models
M
uch broader range than in UCERF2
Off-fault moment rates provided (UCERF2 Type-C zones gone!)
A priori
weights represent an average among those of a special review panelSlide12
Proposed Logic-Tree Branches:
Scaling Relationships
Only HB08 &
EllB
used in UCERF2
Equal
a priori weightsSlide13
Proposed Logic-Tree Branches:
Slip Along Rupture (
D
sr
)
Added Boxcar option
Equal a priori weights
Weldon
et al
. (
2007
) Average
of 13 large events
???
Characteristic Slip?
???Slide14
Proposed Logic-Tree Branches:
Total
M
≥
5
Event Rate
Per year, inside RELM regionFrom Felzer (Appendix L)UCERF2 had single value of 7.5, which is at the low end here (new best estimate of 8.7 represents a 16% increase)Slide15
Proposed Logic-Tree Branches:
Inversion Model
(Fault-Section Nucleation MFD)
Characteristic
UCERF2 Constrained:
* if
Type-A in UCERF2, use UCERF2 nucleation MFD instead.
UCERF2 type MFD
1/3 GR and 2/3
Char
Gutenberg-Richter Constrained:
b
=1Slide16
Proposed Logic-Tree Branches:
Inversion Model
(Fault-Section Nucleation MFD)
???
Use only
Characteristic
???
???
If
Gutenberg-Richter
requires reducing slip rates by ~40%, how many would give it a relative weight > 10%?
???Slide17
Proposed Logic-Tree Branches:
M
max
Off Fault
UCERF2 had “off-fault” values of either 7.0 or 7.6
El Mayor-
Cucapah exceeded 7.0; so we’ve increased to 7.2 at the low endThe value of 8.0 is newWeights are different for
Char
vs
GR
branches
UCERF2
M
maxSlide18
Proposed Logic-Tree Branches:
Off-Fault Spatial
Seis
PDF
Three options, with two new ones:
UCERF3 Smoothed
Seis
Deformation Model Ave
3 more could be added (1 for each deformation model)
Weights are different for
Char
vs
GR
branchesExactly how these are used shortly…Slide19
Proposed Logic-Tree Branches:
Off-Fault Spatial
Seis
PDF
UCERF2 Smoothed Seismicity
UCERF3 Smoothed Seismicity
Average Deformation Model
L
og10(
P
rob
) for Each Grid Cell
(values sum to 1.0)
ABM
NeoKinema
Zeng
???Use deformation-model-specific off-fault spatial PDFs???Slide20
Proposed Logic-Tree Branches:
Fault Moment-Rate Fixes
This deals with cases where fault moment rates are too high to satisfy all data
Currently only an issues for
GR
branches?
More on this shortlySlide21
Grand Inversion Results
Data
Fits:
- Regional MFDs - Slip-rate fits -
Paleo event-rate & ave-slip fits - Tabulation of equation-set fits and
other metrics (e.g., implied CC)Implications Plots: - Participation rate maps
-
Parent
-section
MFDs (also tabulated)
- Correlation
between
paleo
sites
- Implied segmentation (e.g., on SAF) - Fault-jumping statistics - Slip COVs (e.g., Hecker et al.) - Lots of stuff in SCEC VDOERF-Based Plots: - MFDs in LA and SF Boxes
- Hazard
curves at sites
- Hazard
Maps
- RTGM
at sites
- Statewide
Losses
We currently have these (and more) implemented, although we haven’t yet had time to examine everything
Evaluation Metrics:Slide22
Mean, Min, and Max from all logic-tree branches
UCERF3 Mean
UCERF3 Mean Cumulative
UCERF2