1 rupture source and earthquake rate models - introduction€¦ · pg&e dcpp sshac study 3...

1

PG&E DCPP SSHAC Study

Rupture Source and Earthquake Rate Models - Introduction TI Team Evaluation Steve Thompson

Diablo Canyon SSHAC Level 3 PSHA Workshop #3

Feedback to Technical Integration Team on Preliminary Models March 25-27, 2014

San Luis Obispo, CA

PG&E DCPP SSHAC Study 2

SSC Elements for Logic Tree

Fault Model Deformation Model

Rupture Model Earthquake Rate Model Recurrence Model


Overview of Rupture Source and Earthquake Rate Models

Goals: • Capture combinations of fault sections that

may rupture together • Account for absence of behavioral information • Consider alternative approaches (e.g., LTSP,

UCERF2, UCERF3) • Generate earthquake size distribution on the

fault sources that captures the CBR of TDI


UCERF 3.3 Released late 2013 Data, Model, Methods

considered for CBR of TDI

Not a branch of Preliminary logic tree

Data, concepts are incorporated as a guide to Preliminary model approach


San Andreas (Cholame) Fault

UCERF 3.3. Rupture Participation Plot


UCERF 3.3. Rupture Participation Plot

Hosgri Fault


Rupture Model

Approach is to consider: • Alternative fault combinations (Rupture

Sources) that include the “Key” fault sources* • Intersection relationships with adjacent faults

• Relative “likelihood” of the alternative rupture sources

• Rupture Source slip rates should sum to fault slip rates (Deformation Model)

*Concentrating on the portions closest to DCPP


Different treatment for the three Fault Models

NE Model SW Model OV Model


Example of Rupture Model

(Outward Vergent Fault Model)

Consider ways Los

Osos fault may rupture with adjacent faults


Rupture Model OV-17

1. Linkages along strike No evidence for a

stepover greater than 5 km

2. Changes in Slip Sense along strike (“Complex” rupture)


Rupture Model OV-15

3. Rupture at different locations

(Dip differences)


Rupture Model OV-12

4. Splay rupture with adjacent faults

Possible combined rupture of Los Osos + San Luis Bay


OV Rupture Model Table OV

model Scenario Primary fault Other faults Rupture Category MFD Type Slip Sense

OV-01 Hosgri Central to MTJ Hosgri Central link Maximum ss OV-02 Hosgri West to MTJ Hosgri West link Maximum ss OV-03 Hosgri East to MTJ Hosgri East link Maximum ss

OV-04 Piedras Blancas, Western Reach Hosgri and South Hosgri Hosgri Central Piedras Blancas

Anticlinorium complex Maximum ss,rev

OV-05 Shoreline full Shoreline char Characteristic ss OV-06 Shoreline and Hosgri north Shoreline Hosgri North link Maximum ss OV-07 Shoreline and full Hosgri Shoreline Hosgri Central splay Maximum ss

OV-08 Shoreline N and San Luis Bay "Hockey Stick" Shoreline San Luis Bay complex Characteristic ss,rev

OV-09 Shoreline N, Hosgri, and SLB "max Hockey Stick" Shoreline Hosgri, San Luis Bay complex Maximum ss,rev

OV-10 San Miguelito, Wilmar Ave, Nipomo, and south San Miguelito Wilmar Ave, Nipomo,

Foxen Canyon, Little Pine complex Maximum ss,rev

OV-11 San Luis Bay, Mallagh to Shoreline San Luis Bay char Characteristic rev OV-12 SLB with Los Osos backthrust San Luis Bay Los Osos full splay Characteristic rev OV-13 Oceano and SWBZ Oceano Foxen Canyon, Little Pine link Characteristic rev-obl OV-14 Wilmar Avenue proper Wilmar Avenue char Characteristic rev OV-15 Los Osos full Los Osos char Characteristic ss-obl OV-16 Los Osos east and Edna Edna Los Osos East link Characteristic ss-obl OV-17 Los Osos West and Hosgri Los Osos Hosgri complex Maximum ss-obl,ss


SW Rupture Model Table SW model Scenario Primary fault Other faults Rupture

Category MFD Type Slip Sense

SW-01 Hosgri Central to MTJ Hosgri Central link Maximum ss

SW-02 Hosgri West to MTJ Hosgri West link Maximum ss

SW-03 Hosgri East to MTJ Hosgri East link Maximum ss

SW-04 West Branch Hosgri and Piedras Blancas

Western Reach Hosgri Piedras Blancas Anticlinorium complex Characteristic ss,rev

SW-05 Shoreline full Shoreline char Characteristic ss

SW-06 Shoreline and Hosgri north Shoreline Hosgri North link Maximum ss

SW-07 Shoreline and full Hosgri Shoreline Hosgri Central splay Maximum ss

SW-08 Shoreline N and SWBZ "Long Hockey Stick" Shoreline San Luis Bay, Oceano, Foxen

Canyon complex Maximum ss,rev

SW-09 Entire SWBZ San Luis Bay Oceano to Little Pine; Wilmar as splay splay Maximum rev

SW-10 SLB with Los Osos backthrust San Luis Bay Los Osos west splay Characteristic rev

SW-11 Wilmar Avenue and Los Osos East Wilmar Avenue Los Osos East, Nipomo splay Characteristic rev

SW-12 San Luis Bay, Mallagh to Shoreline San Luis Bay char Characteristic rev

SW-13 Los Osos offshore Los Osos offshore char Characteristic rev

SW-14 Oceano and SWBZ Oceano Foxen Canyon, Little Pine link Characteristic rev

SW-15 Wilmar Avenue proper Wilmar Avenue char Characteristic rev


NE model Scenario Primary fault Other faults Rupture Category MFD Type Slip Sense

NE-01 Hosgri Central to MTJ Hosgri Central link Maximum ss NE-02 Hosgri West to MTJ Hosgri West link Maximum ss NE-03 Hosgri East to MTJ Hosgri East link Maximum ss

NE-04 Piedras Blancas, Western Reach Hosgri and South Hosgri Hosgri Central Piedras Blancas Anticlinorium complex Maximum ss,rev

NE-05 Shoreline full Shoreline char Characteristic ss NE-06 Shoreline and Hosgri north Shoreline Hosgri North link Maximum ss NE-07 Shoreline and full Hosgri Shoreline Hosgri Central splay Maximum ss

NE-08 Shoreline N and San Luis Bay "Hockey Stick" Shoreline San Luis Bay complex Characteristic ss,rev

NE-09 Shoreline N and SWBZ "Long Hockey Stick" Shoreline San Luis Bay, Oceano, Foxen

Canyon complex Maximum ss,rev

NE-10 Los Osos wall to wall Los Osos Los Osos east char Characteristic rev NE-11 Los Osos with SLB backthrust Los Osos San Luis Bay splay Characteristic rev NE-12 Los Osos Los Osos char Characteristic rev

NE-13 Los Osos, Wilmar Avenue, Oceano, and SWBZ faults Los Osos Wilmar Ave, Nipomo, Foxen

Canyon, Little Pine splay Maximum rev

NE-14 Los Osos and Hosgri Los Osos Hosgri complex Maximum rev,ss NE-15 Los Osos East and Wilmar Ave Los Osos East Wilmar Ave. splay Characteristic rev NE-16 Oceano and SWBZ Oceano Foxen Canyon, Little Pine link Characteristic rev

NE Rupture Model Table


Rupture Model Each Fault Model has ~15 distinct

Rupture Sources that involve the key faults

The total fault slip rate is partitioned among the Rupture Sources. The partitioning is based on TI Team judgment about the relative likelihood of each rupture source

The methods to evaluate this forward model approach may include inspection of “participation MFDs”


UCERF3.3 Participation MFDs

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

5.0 6.0 7.0 8.0 9.0

Annu

al R

ate

of E

xcee

danc

e (y

r-1)

Magnitude (M)

Hosgri mean

Hosgri minimum

Hosgri maximum


OV: Rupture Model Rate Allocation Target Percent Allocation Mean Fault Slip Rates (mm/yr)

OV model Hosgri Shoreline Los

Osos-Irish Hills

San Luis Bay

Mean Rupture Rate (mm/yr) Hosgri Shoreline

Los Osos-

Irish Hills

San Luis Bay

OV-01 41% 0.75 0.75 OV-02 38% 0.7 0.7 OV-03 8% 0.15 0.15 OV-04 11% 0.2 0.2 OV-05 31% 0.05 0.05 OV-06 19% 0.03 0.03 OV-07 1% 13% 0.02 0.02 0.02 OV-08 19% 18% 0.03 0.03 0.03

OV-09 19% 18% 0.03 0.03 0.03

OV-10 0.05 OV-11 35% 0.06 0.06

OV-12 19% 29% 0.05 0.05 0.05

OV-13 0.15 OV-14 0.16 OV-15 52% 0.14 0.14 OV-16 0.05 OV-17 30% 0.08 0.08

100% 100% 100% 100% Sum: 1.82 0.16 0.27 0.17 Target: 1.82 0.16 0.27 0.17

P[S] 100% 100% 100% 100%


OV: Rupture Model Rate Allocation Percent of fault slip rate total assigned to Rupture Sources

OV model Hosgri Shoreline Los Osos-Irish Hills

San Luis Bay

Piedras Blancas-W

Hosgri Extension

Los Osos offshore

Los Osos East

Wilmar Ave / Los

Berros Oceano Edna San

Miguelito

Outward Mean

Rupture Slip Rate (mm/yr)

OV-01 41% 0.75 OV-02 38% 0.7 OV-03 8% 0.15 OV-04 11% 100% 0.2 OV-05 31% 0.05 OV-06 19% 0.03 OV-07 1% 13% 0.02 OV-08 19% 18% 0.03 OV-09 19% 18% 13% 0.03 OV-10 21% 100% 0.05 OV-11 35% 0.06 OV-12 19% 29% 0.05 OV-13 100% 0.15 OV-14 67% 0.16 OV-15 52% 70% 108% 0.14 OV-16 38% 100% 0.05 OV-17 30% 40% 0.08

~P(S): 100% 100% 100% 100% 100% 110% 146% 100% 100% 100% 100% Seismogenic

Fault SR: 1.82 0.16 0.27 0.17 0.2 0.22 0.19 0.24 0.15 0.05 0.05


SW: Rupture Model Rate Allocation Percent of fault slip rate total assigned to Rupture Sources

SW model Hosgri Shoreline Los Osos-Irish Hills

San Luis Bay

Piedras Blancas-W Hosgri Extension

Los Osos offshore

Los Osos East

Wilmar Ave / Los


Miguelito

SW Mean Rupture Slip Rate (mm/yr)

SW-01 49% 0.9

SW-02 41% 0.75

SW-03 8% 0.15

SW-04 100% 0.2

SW-05 50% 0.08

SW-06 19% 0.03

SW-07 1% 13% 0.02

SW-08 19% 20% 0.03

SW-09 30% 32% 47% 0.07

SW-10 50% 43% 0.1

SW-11 100% 45% 0.1

SW-12 26% 0.06

SW-13 100% 0.2

SW-14 33% 0.05

SW-15 23% 0.05

~P(S): 100% 100% 50% 100% 100% 100% 100% 100% 100% 0% 0% Seismogenic

Fault SR: 1.82 0.16 0.10 0.23 0.20 0.20 0.10 0.22 0.15 0.00 0.00


NE: Rupture Model Rate Allocation Percent of fault slip rate total assigned to Rupture Sources

NE model Hosgri Shoreline Los Osos-Irish Hills

San Luis Bay

Piedras Blancas-W Hosgri Extension

Los Osos offshore

Los Osos East

Wilmar Ave / Los


Miguelito

NE Mean Rupture Slip Rate (mm/yr)

NE-01 41% 0.75 NE-02 38% 0.7 NE-03 8% 0.15 NE-04 11% 100% 0.2 NE-05 44% 0.07 NE-06 19% 0.03 NE-07 1% 13% 0.02 NE-08 19% 18% 0.03 NE-09 6% 7% 0.01 NE-10 5% 18% 0.02 NE-11 23% 59% 0.1 NE-12 27% 0.12 NE-13 23% 50% 50% 67% 0.1 NE-14 23% 50% 0.1 NE-15 82% 45% 0.09 NE-16 27% 0.04 ~P(S): 100% 100% 100% 76% 100% 100% 100% 95% 100% 0% 0%

Seismogenic Fault SR: 1.82 0.16 0.44 0.13 0.20 0.20 0.11 0.19 0.15 0.00 0.00


Example Rupture Model Rate Logic Trees

00.20.40.60.8

1

0.001 0.01 0.1 1 10

Cum

ulat

ive

Prob

abili

ty

Slip Rate (mm/yr)

[0.101]

2.5 mm/yr

[0.244]

[0.244]

[0.101]

1.7 mm/yr

1.1 mm/yr

0.6 mm/yr

[0.309]

3.3 mm/yr

Branch Slip Rate (mm/yr) Weight

OV-01 (41%)

0.11 0.248 0.63 0.504 1.65 0.248

OV-02 (38%)

0.10 0.248 0.59 0.504 1.54 0.248

OV-03 (8%)

0.02 0.248 0.13 0.504 0.33 0.248

OV-04 (11%)

0.03 0.248 0.17 0.504 0.43 0.248

OV-07 (1%)

0.003 0.248 0.02 0.504 0.04 0.248

Hosgri Rupture Sources


Rupture Model Iteration with Hazard Analyst is

expected, and basis for the rate allocation will be an important part of documentation.

Hazard sensitivity will be important to show the degree to which this approach is hazard sensitive and how it may compare to more traditional, epistemic-minded approaches.


SSC Elements for Logic Tree

Fault Model Deformation Model

Rupture Model Earthquake Rate Model Recurrence Model


Earthquake Rate Model

Approach is to consider: • Alternative functional forms of the magnitude

probability distribution function (PDF) • Alternative maximum (Mmax), and

“characteristic” (Mchar) magnitudes to accompany each Rupture Source • Consideration of fault length scales and widths • Consideration of magnitude-scaling relations

Describes the size distribution of earthquakes (ruptures) that occur on the Rupture Sources.


Earthquake Rate Model – Two Rupture Model Categories

“Maximum” Rupture Sources “Characteristic” Rupture Sources

Rupture Model OV-15

Rupture Model OV-17


Magnitude PDF alternatives

Exponential Characteristic

(YC85)

0.0001

0.001

0.01

0.1

5 5.5 6 6.5 7 7.5 8

Annu

al R

ate

(yr-1

)

Magnitude

GR

YC85


Magnitude PDF alternatives

Modified YC85 (WACY):

Exponential Characteristic Tail


Earthquake Rate Model: Logic Tree for Maximum-Type Sources

Magnitude PDF

[0.9]

Modified YC85 (WACY)

Exponential (G-R) [0.1]

Char Magnitude Max Magnitude

N/A Mmax 2

Mmax 3

Mmax 1

Mmax 2

Mmax 3

Mmax 1

Mchar 2

Mchar 3

Mchar 1


Earthquake Rate Model: Logic Tree for Characteristic-Type Sources

Magnitude PDF

[1.0]

Characteristic (YC85)

Char Magnitude Max Magnitude

Mchar 2

Mchar 3

Mchar 1

Mchar 2 + 0.25

Mchar 3 + 0.25

Mchar 1 + 0.25


Earthquake Rate Model – Selection of Magnitudes Mmax and Mchar estimates are based on length

scales observed along the faults and estimated fault widths based on dip and seismogenic thickness

The length scales represent alternative hypotheses of “characteristic” earthquake sizes

Segmentation criteria are applied for the length scales following concepts such as:

Slip rate changes Fault bends and stepovers Changes in rake Fault intersections


Earthquake Rate Model – Selection of Magnitudes (cont.)

Lacking fault-specific behavioral activity, and acknowledging that segmentation criteria are problematic to defend rigorously based on empirical data:

1. Adding Epistemic uncertainty casts a broad range 2. Aleatory variability is added through the rupture

model concept

0

10

20

30

40

50

60

5.9 6.1 6.3 6.5 6.7 6.9 7.1 7.3 7.5 7.7 7.9 8.1 8.3 8.5

Coun

t

Magnitude

OV Model, All Magnitudes, Branch Weighted

Mchar

Mmax


Earthquake Rate Model – Magnitude Distribution

0

10

20

30

40

50

60

5.9 6.1 6.3 6.5 6.7 6.9 7.1 7.3 7.5 7.7 7.9 8.1 8.3 8.5

Coun

t

Magnitude

OV-Model, All Magnitudes, Branch Weighted

Mchar

Mmax

0

20

40

60

80

100

120

5.9 6.1 6.3 6.5 6.7 6.9 7.1 7.3 7.5 7.7 7.9 8.1 8.3 8.5

Coun

t

Magnitude

OV-Model, All Magnitudes, Branch Weighted, Boxcar Smoothed

Mchar

Epistemic +

Rupture Model aleatory

+ Boxcar aleatory


0

5

10

15

20

25

30

5.9 6.1 6.3 6.5 6.7 6.9 7.1 7.3 7.5 7.7 7.9 8.1 8.3 8.5

Coun

t

Magnitude

OV-Model, Hosgri vs. Everything Else, Branch Weighted

Everything ElseMcharEverything ElseMmaxHosgri Mchar

Hosgri Mmax



0

100

200

300

400

500

600

700

800

5.9 6.1 6.3 6.5 6.7 6.9 7.1 7.3 7.5 7.7 7.9 8.1 8.3 8.5

Coun

t

Magnitude

OV-Model, Hosgri vs. Everything Else, Slip Rate Weighted

Everything ElseMchar

Everything ElseMmax

Hosgri Mchar

Hosgri Mmax



Earthquake Rate Model – Selection of Magnitudes (cont.) Magnitudes are derived from consideration of several

Magnitude-Scaling Relations, and rounding to the nearest tenth.

Magnitude-Area Scaling Relations are given the most consideration. Area scaling can be most closely related to moment, and log A + 4 fit the NGA database well.

Magnitude-Length Scaling Relations are given less consideration, as they are more removed from seismic moment, more difficult to use in the most hazard-significant M6-7 range, and don’t appear to fit the Area relations at any magnitude range. These may need additional evaluation.


Earthquake Rate Model – Magnitude-Area Scaling Relations Hanks and Bakun (2002) 𝑀𝑊 = log𝐴 + 3.98 ± 0.03 , for 𝐴 ≤ 537 𝑘𝑘2

𝑀𝑊 = 43

log𝐴 + 3.07 ± 0.04 , for 𝐴 > 537 𝑘𝑘2

Shaw (2009; 2013)

𝑀 = log10 𝐴 +23 log10

max 1, 𝐴𝑊2

1 + max(1, 𝐴7.4𝑊2) /2

+ 3.98

Hanks and Bakun (2014) 𝑀𝑊 = log𝐴 + 3.98, for 𝐴 ≤ 537 𝑘𝑘2

𝑀𝑊 = 54

log𝐴 + 3.30, for 𝐴 > 537 𝑘𝑘2

Wells and Coppersmith (1994) 𝑀 = 4.07 + 0.98 log𝐴 (all events) 𝑀 = 3.98 + 1.02 log𝐴 (strike-slip events)


Earthquake Rate Model – Magnitude-Length Scaling Relations

Stirling et al. (2008)

𝑀𝑊 = 4.18 + 23

log𝑊 + 43

log 𝐿

Wesnousky (2008) 𝑀𝑊 = 5.30 + 1.02 log 𝐿 (all events) 𝑀𝑊 = 5.56 + 0.87 log 𝐿 (strike-slip events)

Wells and Coppersmith (1994) – SRL 𝑀 = 5.08 + 1.16 log 𝐿 (all events) 𝑀 = 5.16 + 1.12 log 𝐿 (strike-slip events)

Wells and Coppersmith (1994) – RLD 𝑀 = 4.38 + 1.49 log 𝐿 (all events) 𝑀 = 4.33 + 1.49 log 𝐿 (strike-slip events)



Plot of Magnitude Scaling Relations (From Shaw, 2013a)

WG03 data Red: W<15 km Cyan: W>15 km

Compilation data Red: HB08 dataset Cyan: Biasi et al. (2013) data

S09', W=15 S09', W=11 HB02 WC94 EB03



Plot of Magnitude Scaling Relations (SSC TI Team)

5

5.5

6

6.5

7

7.5

8

8.5

10 100 1000 10000

Mag

nitu

de (M

)

Rupture Area (km2)

S09'_Wmax15S09'_Wmax19HB02HB14StrNZ08_Wmax15StrNZ08_Wmax19HB08 Dataset



Example Table


Rupture and EQ Rate Model The methods to evaluate this

forward model approach may include inspection of “participation MFDs”

Considering guidance from

UCERF3.3 results


UCERF3.3 Participation MFDs

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

5.0 6.0 7.0 8.0 9.0

Annu

al R

ate

of E

xcee

danc

e (y

r-1)

Magnitude (M)

Hosgri mean

Hosgri minimum

Hosgri maximum

44

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