WGCEPNSHMP Fault Rupture Models - PowerPoint PPT Presentation

Title: WGCEPNSHMP Fault Rupture Models


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WGCEP/NSHMP Fault Rupture Models
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Type-B Faults MoRate from slip rate Mchar
from M(A) 67 MoRate in Mchar (full fault
ruptures) 33 MoRate in GR-Dist between M 6.5
and Mchar (higher Mchar ---gt lower rates)
Type-A Faults Segment allow both single- and
multi-segment ruptures Mrup from M(A) also
gives implied ave slip Get rupture rates by
satisfying slip rates and mean recurrence
intervals
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Type-A Fault Rupture Models
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If S segments, then RS(S1)/2 different ruptures
involving contiguous segments. We want the
long-term rate (fr) of each rth rupture. We know
for each segment Slip Rate (vs) Mean Recur Int
(Ts1/?s) Constraints are Equation Set
(1) Equation Set (2) Equation Set
(3) Positivity where Dsr is the average
slip in the rth rupture on the sth segment, and
Gsr is a matrix indicating whether the rth
rupture involves the sth segment (1 if so, 0 if
not).
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Adj Params (logic-tree Branches)
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Using Ellsworth-B M(A)
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Using Somerville (2006) M(A)
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Current WGCEP Solution
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Ellsworth B M(A) Tapered slip model
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Current WGCEP Solution
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Somerville M(A) Tapered slip model
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Current WGCEP Solution
Define the following a-priori rupture rate
models that solve (equation set 2)

• Minimum Rate Solution - That which minimizes the
  total rate of ruptures (and therefore maximizes
  event magnitudes), consistent with obs, and with
  branch weight of 10.
• Maximum Rate Solution - That which maximizes
  the total rate of ruptures (and therefore
  minimizes event magnitudes), consistent with obs,
  and with branch weight of 10.
• Geological Insight Solution(s) - Those that
  makes all fr as close as possible to preferred,
  complete sets defined by geologists, consistent
  with obs.

(These dont span solution space, but should span
hazard/loss space?)
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Current WGCEP Solution

• Choose an a-priori rupture rate model that
  solves equation set (2) (min-rate, max-rate, or a
  geol-insight model)
• Choose an assumed Dsr from the following
• Dsr Ds (Characteristic Slip e.g.,
  WGCEP-1995)
• Dsr proportional to vs (WGCEP-2002 Slip)
• Dsr Dr (Uniform/Boxcar)
• Dsr - Tapered Ends (Elliptical)
• If Characteristic Slip not chosen above, choose
  a Mag-Area Relationship
• Ellsworth A (WGCEP-2002)
• Ellsworth B (WGCEP-2002)
• Hanks and Bakun (2002)
• Somerville (2006), which is Wells Coppersmith
  (1994)
• Also choose Deformation model whether Aseismic
  Slip Factor reduces area or slip rate and
  Gaussian-MFD sigma and trunc level (same for all
  ruptures)
• Solve for final, moment-balanced rupture rates