Workshop on Fault Segmentation and FaultToFault Jumps in Earthquake Rupture March 1517, 2006 Convene

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Workshop onFault Segmentation and
Fault-To-Fault Jumps in Earthquake
Rupture(March 15-17, 2006)Convened by Ned
Field, Ray Weldon, Ruth Harris, David Schwartz,
David Oglesby on behalf of the WGCEP
(http//www.WGCEP.org)
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Workshop Goals
(reevaluate current segmentation models and
explore alternatives)

• Agenda
• Weds Thurs
• Hear from experts and discuss
• Friday
• Decide what WGCEP should do

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Working Group on California Earthquake
Probabilities (WGCEP) Development of a Uniform
California Earthquake Rupture Forecast (UCERF)
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WGCEP Goals
To provide the California Earthquake Authority
(CEA) with a statewide, time-dependent ERF that
uses best available science and is endorsed by
the USGS, CGS, and SCEC, and is evaluated by
Scientific Review Panel (SRP) and
CEPEC Coordinated with the next National Seismic
Hazard Mapping Program (NSHMP) time-independent
model CEA will use this to set earthquake
insurance rates (they want 5-year forecasts,
maybe 1-year in future)
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Funding Most from CGS, SCEC,
USGS 1,750,000 from CEA (22 of total)
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SCEC will provide CEA with a single-point
interface to the project.
WGCEP Organization Funding Sources
CEA
Geoscience organizations
SCEC
NSF
Management oversight committee
Scientific review panel
USGS Menlo Park
USGS
MOC
SRP
Sources of WGCEP funding
USGS Golden
CGS
State of CA
WGCEP ExCom
Working Group on California Earthquake
Probabilities
Working group leadership

Subcom. A
Subcom. B
Subcom. C

Task-oriented subcommittees
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WGCEP Management

• WGCEP Management Oversight Committee (MOC)
• SCEC Thomas H. Jordan (CEA contact)
• ? USGS, Menlo Park Rufus Catchings
• USGS, Golden Jill McCarthy
• CGS Michael Reichle

In charge of resource allocation and approving
all project plans, budgets, and schedules Their
signoff will constitute the SCEC/USGS/CGS
endorsement
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• WGCEP Executive Committee
• Edward (Ned) Field SCEC/USGS, Pasadena
• ? Thomas Parsons, USGS, Menlo Park
• Chris Wills, CGS
• Ray Weldon, SCEC/UofO
• Mark Petersen, USGS, Golden
• Ross Stein, USGS, Menlo Park

Responsible for convening experts, reviewing
options, making decisions, and orchestrating
implementation of the model and supporting
databases Role of leadership is not to advocate
models, but to accommodate whatever models are
appropriate
Key Scientists Provide expert opinion and/or
specific model elements - likely receiving
funding documenting their contributions.
Contributors
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• Scientific Review Panel
• Bill Ellsworth (chair)
• Art Frankel
• David Jackson
• Jim Dieterich
• Lloyd Cluff
• Allin Cornell
• Mike Blanpied
• David Schwartz

This group will ultimately decide whether weve
chosen a minimum set of alternative models that
adequately spans the range of viable 5-year
forecasts for California
CEPEC Lucile Jones Duncan Agnew Tom
Jordan Mike Reichle Jim Brune David
Openheimer William Lettis Paul Segall John
Parrish
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UCERF Model Components
Fault Model(s)
(A)
Black Box
Deformation Model(s)
(B)
Black Box
(C)
Earthquake Rate Model(s)
Black Box
(D)
Earthquake Prob Model(s)
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UCERF Model Components
Fault Model(s)
(A)
Black Box
Instrumental Qk Catalog
Deformation Model(s)
Fault Section Database
Historical Qk Catalog
(B)
Black Box
(C)
Earthquake Rate Model(s)
GPS Database
Black Box
(D)
Paleo Sites Database
Earthquake Prob Model(s)
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UCERF Model Components
Fault Model(s)
(A)
Black Box
Instrumental Qk Catalog
Deformation Model(s)
Fault Section Database
Historical Qk Catalog
(B)
Black Box
(C)
Earthquake Rate Model(s)
GPS Database
Black Box
(D)
Paleo Sites Database
Earthquake Prob Model(s)
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UCERF Model Components
Fault Model(s)
(A)
Black Box
Instrumental Qk Catalog
Deformation Model(s)
Fault Section Database
Historical Qk Catalog
(B)
Black Box
(C)
Earthquake Rate Model(s)
GPS Database
Black Box
(D)
Paleo Sites Database
Earthquake Prob Model(s)
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UCERF Model Components
Fault Model(s)
(A)
Black Box
Instrumental Qk Catalog
Deformation Model(s)
Fault Section Database
Historical Qk Catalog
(B)
Black Box
(C)
Earthquake Rate Model(s)
GPS Database
Black Box
(D)
Paleo Sites Database
Earthquake Prob Model(s)
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UCERF Model Components
Fault Model(s)
(A)
Black Box
Instrumental Qk Catalog
Deformation Model(s)
Fault Section Database
Historical Qk Catalog
(B)
Black Box
(C)
Earthquake Rate Model(s)
GPS Database
Black Box
(D)
Paleo Sites Database
Earthquake Prob Model(s)
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Main Delivery Schedule

• February 8, 2006 (to CEA)
• UCERF 1
• Aug 31, 2006 (to CEA)
• Earthquake Rate Model 2 (preliminary for NSHMP)
• June 1, 2007 (to NSHMP)
• Final, reviewed Earthquake Rate Model 2
• (for use in 2007 NSHMP revision)
• September 30, 2007 (to CEA)
• UCERF 2 (reviewed by SRP and CEPEC)

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Issues/Possible Innovations

• Statewide model
• Use of SCEC CFM (including alternatives)
• Use GPS data via kinematically consistent
  deformation model(s)
• Relax strict segmentation (if appropriate)
• Allow fault-to-fault jumps (if appropriate)
• Apply consistent time-dependent models (esp. with
  (4) (5))
• Include earthquake triggering effects
• Deploy as extensible, adaptive (living) model.
• Simulation enabled

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Issues/Possible Innovations
1) Statewide model
WGCEPs
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Issues/Possible Innovations
2) Use of SCEC Community Fault Model
(including alternatives)
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Issues/Possible Innovations
3) Use GPS data via kinematically consistent
deformation model(s)
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Fault Models(s)
Black Box
Deformation Model(s)
We want 1) Improved slip rates on major
faults 2) Strain rates elsewhere 3) GPS data
included
Black Box
Earthquake Rate Model(s)
4) Kinematically consistent 5) Accommodate
all important faults 6) Can accommodate
alternative fault models 7) Accounts for
geologic and geodetic data uncertainties 8)
Includes viscoelastic effects 9) Includes
significant 3D effects 10) Statewide application
Black Box
Earthquake Prob Model(s)
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No model has all these attributes
Fault Models(s)
Are any existing models better than sticking to
what we have? WGCEP recommending pursuit of
Black Box
Deformation Model(s)
NeoKinema Harvard-MIT Block Model Parsons
FEM Shen Zeng Perhaps others

• We want
• 1) Improved slip rates on major faults
• 2) Deformation rates elsewhere
• 3) GPS data included
• 4) Kinematically consistent
• 5) Accommodate all important faults
• 6) Can accommodate alternative fault models
• 7) Accounts for geologic and geodetic data
  uncertainties
• 8) Includes viscoelastic effects
• 9) Includes significant 3D effects
• 10) Statewide application

Black Box
Earthquake Rate Model(s)
Black Box
Earthquake Prob Model(s)
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No model has all these attributes
Fault Models(s)
Are any existing models better than sticking to
what we have? WGCEP recommending pursuit of
Black Box
Deformation Model(s)
NeoKinema Harvard-MIT Block Model Parsons
FEM Shen Zeng Perhaps others
Black Box
Delivery will be revised slip rates on modeled
faults (and perhaps deformation rates elsewhere,
and stressing rates on faults)
Earthquake Rate Model(s)
Black Box
Earthquake Prob Model(s)
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Issues/Possible Innovations
4) Relax strict segmentation
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Issues/Possible Innovations
4) Relax strict segmentation
But ...
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Issues/Possible Innovations
4) Relax strict segmentation
Does it matter (all models are discretized to
some extent)?
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Issues/Possible Innovations
5) Allow fault-to-fault jumps
No previous WGCEPs have allowed such ruptures.
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Issues/Possible Innovations
5) Allow fault-to-fault jumps
But ...
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Issues/Possible Innovations
5) Allow fault-to-fault jumps
Fault Interactions and Large Complex Earthquakes
in the Los Angeles Area Anderson, Aagaard,
Hudnut (2003, Science 320, 1946-1949) We find
that a large northern San Jacinto fault
earthquake could trigger a cascading rupture of
the Sierra Madre-Cucamonga system, potentially
causing a moment magnitude 7.5 to 7.8 earthquake
on the edge of the Los Angeles metropolitan
region.
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Issues/Possible Innovations
5) Allow fault-to-fault jumps
Can dynamic rupture modelers help define
fault-to-fault jumping probabilities?
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Issues/Possible Innovations
6) Figure out how to apply elastic-rebound-motivat
ed renewal models properly
Problem how to compute conditional
time-dependent probabilities when you allow both
single and multi-segment ruptures (let alone
relaxing segmentation)? There seems to be a
logical inconsistency with the way previous
WGCEPs have modeled this
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From WGCEP-2002
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From WGCEP-2002
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How then do we compute conditional probabilities
where we have single and multi-segment ruptures?
We have ideas
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Issues/Possible Innovations
7) Include earthquake triggering effects
CEA wants 1- to 5-year forecasts
This is between the 30-year forecasts of
previous WGCEPs (renewal models) and the 24-hour
forecasts of STEP (the CEPEC-endorsed model based
on aftershock statistics)
We are attempting to design a framework that
could accommodate a variety of alternative
approaches (e.g., from RELM)
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Issues/Possible Innovations
8) Deploy as extensible, adaptive (living) model.
i.e., modifications can be made as warranted by
scientific developments, the collection of new
data, or following the occurrence of significant
earthquakes. The model can be living to the
extent that update evaluation process can occur
in short order. CEA wants this.
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Issues/Possible Innovations
9) Simulation enabled (i.e, can generate
synthetic catalogs)
Needed to go beyond next-event forecasts if
stress interactions and earthquake triggering are
included Helpful (if not required) to understand
model behavior Can be used to calibrate the
model (e.g., moment in aftershocks) If we can
deal with simulated events, well be ready for
any real events
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Implementation Plan

• Guiding principles
• If it aint broke, dont fix it
• Some of the hoped-for innovations wont work out
• Everything will take longer than we think
• Build components in parallel (not in series)
• Get a basic version of each component implemented
  ASAP, and add improved versions when available

We cannot miss the NSHMP and CEA delivery
deadlines!
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UCERF 1.0
Fault Model 1.0
NSHMP-2002 Fault Model
By Feb. 8, 2006
Black Box
Deformation Model 1.0
NSHMP-2002 Fault Slip Rates
NSHMP-2002 Earthquake Rate Model
Black Box
Earthquake Rate Model 1.0
Black Box
Earthquake Prob Model 1.0
Simple conditional probabilities based on date of
last earthquakes
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UCERF 2.0
Fault Models 2.X
Revision of NSHMP-2002 Fault Model based on SCEC
CFM (including alternatives) any desired
changes for N. California
By Sept. 30, 2007
Black Box
Deformation Model 2.0
Revised slip rates for elements in Fault Model
2.0, perhaps constrained by GPS data.
New model based on reevaluation of fault
segmentation and cascades (e.g., based on Weldon
et al.) may relax segmentation and allow
fault-to-fault jumps.
Black Box
Earthquake Rate Model 2.0
Black Box
Earthquake Prob Model 2.0
Application of more sophisticated time- dependent
probability calculations
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UCERF 3.0
Fault Models 2.X
Black Box
Deformation Model 3.0
e.g., relax segmentation, allow fault-to-fault
jumps, and use off-fault deformation rates to
help constrain off-fault seismicity.
Black Box
Earthquake Rate Model 3.0
Black Box
Earthquake Prob Model 3.0
e.g., enable real-time modification of
probabilities base on stress or seismicity-rate
changes.
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UCERF 3.0
Fault Models 2.X
Black Box
Deformation Model 3.0
Use of a more sophisticated, California- wide
deformation model such as NeoKinema.
e.g., relax segmentation, allow fault-to-fault
jumps, and use off-fault deformation rates to
help constrain off-fault seismicity.
Black Box
Earthquake Rate Model 3.0
All of these are relatively ambitious and
delivery cannot be guaranteed by 2007.
Black Box
Earthquake Prob Model 3.0
e.g., enable real-time modification of
probabilities base on stress or seismicity-rate
changes.
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Workshop Goals
To determine the spatial extent of all possible
earthquakes on explicitly modeled faults in
California (reevaluate current segmentation
models and explore alternatives)

• Agenda
• Weds Thurs
• Hear from experts and discuss
• Friday
• Decide what WGCEP will do

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Co-Seismic?
Whats the difference between co-seismic and
triggered quickly?

• Constructive interference (e.g., directivity)

• 2) My Earthquake Insurance
• One or more earthquake shocks that occur within
  a seventy-two hour period constitute a single
  earthquake

3) California Earthquake Authority seismic
event everything within a 15-day window
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Current Practice
(WGCEP-2002, NSHMP-2002, UCERF 1)

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NSHMP-2002 UCERF 1 Southern California Type
A Faults

• ?? 0.12
• Trunc /-1.25?

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NSHMP-2002 Bay Area Faults WGCEP-2002

• ?? 0.12
• Trunc /-2?

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NSHMP-2002 B Faults UCERF 1

• 2/3 Mo Char
• 1/3 Mo GR

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An Alternative Approach(?)
(extension of Andrews Schwerer (2000) w/
elements of Field et al. (1999))
2) Define all possible ruptures as every
possible combination of contiguous sections
(contiguous means separated by less than 10
km) Use matrix Irs to indicate whether rth
rupture involves the sth segment
3) Get magnitude of each rupture from mag(area)
relationship this gives average slip (ur) of
each as well
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An Alternative Approach(?)
4) Solve for the long term rate of each rupture
(fr) via linear inversion of
f(m) GR (for entire region)
Anything else (e.g., rupture boundaries)
Solution space represents all possible models
A formal, tractable, extensible, mathematical
framework
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What can geology or dynamic modeling tell us
about what ruptures are more or less probable?
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What can geology or dynamic modeling tell us
about what ruptures are more or less
probable? How do we define and apply these
constraints in our inversion?
Have the simulators solved this problem?
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An Alternative Approach(?)
(extension of Andrews Schwerer (2000) w/
elements of Field et al. (1999))
2) Define all possible ruptures as every
possible combination of contiguous sections
(contiguous means separated by less than 10
km) Use matrix Irs to indicate whether rth
rupture involves the sth segment
3) Get magnitude of each rupture from mag(area)
relationship this gives average slip (ur) of
each as well
58
An Alternative Approach(?)
4) Solve for the long term rate of each rupture
(fr) via linear inversion of
f(m) GR (for entire region)
Anything else (e.g., rupture boundaries)
Solution space represents all possible models
A formal, tractable, extensible, mathematical
framework
59
What can geology or dynamic modeling tell us
about what ruptures are more or less probable?
60
What can geology or dynamic modeling tell us
about what ruptures are more or less
probable? How do we define and apply these
constraints in our inversion?
Have the simulators solved this problem?