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1

PG&E DCPP SSHAC Study

Hosgri Fault Source Slip Rate CDF

TI Team Evaluation S. 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

Overview of Hosgri Slip Rate CDF Goal:

• Construct a slip rate CDF for the Hosgri Source relevant for the reach opposite DCPP.

Approach: • Four geologic study sites to consider • Define uncertainty distributions for lateral

offsets and ages; combine to get slip rate • Consider adjustments or weighting schemes

based on multiple observations, site age, distance from site

• Evaluate results against other data, modeling results

• Revisions expected following report finalization and new data evaluation


Relevant for all three Fault Models

NE Model SW Model OV Model


Sites Four geologic slip rate sites: 1) San Simeon 2) Offshore Pt. Estero* 3) South Estero Bay* 4) Offshore Pt. Sal*

*Evaluation by TI Team in progress

1

2

4

3


San Simeon: Oso Terrace Horizontal Slip Rate

Source: Hanson and Lettis (1994)


San Simeon Slip Rate Assessment

Oso Terrace Offset Oso Terrace Age

0.000

0.005

0.010

0.015

0.020

0 200 400 600 800

Prob

abili

ty

Offset (m)

Paleostrandline offset

0.00

0.05

0.10

160 180 200 220 240 260Pr

obab

ility

Channel Age (ky)

Stage 7 Highstand Age Model

Stage 7 Highstand Age Value (ky) Min -> 190

Best min -> 195 Best max -> 215

Max -> 220

Lateral Offsets Value (m) Min -> 150


Max -> 560

PG&E DCPP SSHAC Study 7 San Simeon Slip Rate

Oso Terrace Slip Rate CDF

Slip Rate Value

(mm/yr) Min -> 0.7 Max -> 2.9

Mean -> 1.8

0

0.2

0.4

0.6

0.8

1

0.5 1.0 1.5 2.0 2.5 3.0

Cum

ulat

ive

Prob

abili

ty

Slip Rate (m/ky)


Offshore Pt. Estero: Cross-Hosgri Slope (S. Johnson, in review, BSSA)

Source: S. Johnson, Presentation to SSHAC TI Team (3/5/2014)


Offshore Pt. Estero: Cross-Hosgri Slope Age Model



Pt. Estero Slip Rate Assessment

CHS Offset CHS Age

CHS Age Value (ky) Min -> 10


Max -> 13

Lateral Offsets Value (m) Min -> 15


Max -> 43

0.00

0.01

0.02

0.03

0.04

0 10 20 30 40 50 60

Prob

abili

ty

Offset (m)

Wave-Face offset

0.00

0.02

0.04

0.06

0.08

8 10 12 14

Prob

abili

ty

CHS Age (ky)

Younger Dryas sealevel rise age model


Pt. Estero Slip Rate Assessment

CHS Slip Rate CDF

Slip Rate Value

(mm/yr) Min -> 1.2 Max -> 4.1

Mean -> 2.6

0

0.2

0.4

0.6

0.8

1

0 1 2 3 4

Cum

ulat

ive

Prob

abili

ty

Slip Rate (m/ky)


Sites Four geologic slip rate sites: 1) San Simeon 2) Offshore Pt. Estero* 3) South Estero Bay* 4) Offshore Pt. Sal*

*Evaluation by TI Team in progress

1

2

4

3


Channel Offset

Total Offset Value (m) Min -> 680 Max -> 1930

Mean -> 1230

Lateral Offsets

West (m)

East (m)

Min -> 450 200 Best min -> 800 250 Best max -> 900 270

Max -> 1650 320

0.00

0.05

0.10

0.15

0.20

0 500 1000 1500 2000

Prob

abili

ty

Channel Offset (m)

West strandoffset

East strandoffset

0

0.2

0.4

0.6

0.8

1

0 500 1,000 1,500 2,000C

umul

ativ

e Pr

obab

ility

Channel Offset (m)

West strand (m)

East strand (m)

Combined W+E (m)

Hosgri Slip Rate Assessment, South Estero Bay Site


Hosgri Slip Rate Assessment, South Estero Bay Site

Channel Age (80/20 weighting)

Slip Rate CDF

Ages Unconformity

model (ky) Sedimentation Rate model (ky)

Min -> 540 540 Best min -> 780 1600 Best max -> 820 1800

Max -> 1400 3500

0.00

0.01

0.02

0.03

0 1000 2000 3000 4000

Prob

abili

ty

Channel Age (ky)

Unconformity AgeModel

Sedimentation RteAge Model

Weighted Age Model

Slip Rate Value

(mm/yr) Min -> 0.3 Max -> 3.2

Mean -> 1.3

0

0.2

0.4

0.6

0.8

1

0.0 0.5 1.0 1.5 2.0 2.5 3.0

Cum

ulat

ive

Prob

abili

ty

Slip Rate (m/ky)

Unconformity agemodel

Sedimentationrate age model

Weighted


Hosgri Slip Rate Assessment, Pt. Sal Site

Channel F Offset

Lateral Offset Value (m) Min -> 376


Max -> 610

0.000

0.005

0.010

0.015

0.020

300 350 400 450 500 550 600 650

Prob

abili

ty

Offset (m)


Hosgri Slip Rate Assessment, Pt. Sal Site

Channel Age Model

Ages (in ky) and Weights

Stage 6 [0.05]

Stage 10 [0.25]

Broad [0.3]

Min -> 125 335 125 Best min -> 135 340 250 Best max -> 140 350 630

Max -> 160 355 1400

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 500 1000 1500

Prob

abili

ty

Channel Age (ky)

Stage 6 (min)

Stage 10 age (best)

Broad

Weighted Age Model

Weighting for Age Model Model Wt Stage 6 0.05

Stage 8 0.1

Stage 10 0.25

Stage 12 0.15

Stage 14 0.1

Stage 16 0.05

Broad 0.3


Hosgri Slip Rate Assessment, Pt. Sal Site Offshore Pt. Sal Channel

Slip Rate CDF

Weighted Slip Rate Value

(mm/yr) Min -> 0.3 Max -> 4.7

Mean -> 1.3

0

0.2

0.4

0.6

0.8

1

0 1 2 3 4 5

Cum

ulat

ive

Prob

abili

ty

Slip Rate (m/ky)

Slip Rate -minimum agemodel

Slip Rate - preferred agemodel

Slip Rate - maximum agemodel

Slip Rate - Weighted


Hosgri Slip Rate Assessment Four Hosgri Sites Slip Rate CDFs

0

0.2

0.4

0.6

0.8

1

0 1 2 3 4 5

Cum

ulat

ive

Prob

abili

ty

Slip Rate, mm/yr

San Simeon / Oso Terrace

Pt. Estero Cross-Hosgri slope

Estero Bay Submarine Channel

Pt. Sal Channel F

Weighting Scheme

San Simeon

Pt. Estero

Estero Bay Pt. Sal

Near-Equal 0.3 0.3 0.2 0.2 Inverse-Age 0.27 0.50 0.07 0.16

Inverse-Distance 0.13 0.22 0.38 0.27


Hosgri Slip Rate Assessment 5-pt distribution for Hosgri fault, Near-Equal weighting:

[0.101]

Weighted mean slip rate: 1.8 mm/yr

2.5 mm/yr

[0.244]

[0.244]

[0.101]

1.7 mm/yr

1.1 mm/yr

0.6 mm/yr

3.3 mm/yr

[0.309]

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3 4 5

Cum

ulat

ive

Prob

abili

ty

Slip Rate, mm/yr

Near-Equal Weighting

Age-Weighted

Distance-Weighted

CDFs for Hosgri fault, alternative weighting schemes:


Hosgri Slip Rate Assessment

Hosgri slip rate: Center: 1.8 mm/yr (wtd mean) Body: 0.6 to 3.4 (95%) Range: 0.26 min; 4.7 max

0

0.2

0.4

0.6

0.8

1

0 1 2 3 4 5

Slip Rate, mm/yr

Hosgri fault slip rate CDFs Other constraints: 1) GPS plate boundary: 0.5 to 4

mm/yr 2) USGS Block modeling: 0.5 to

~3 mm/yr 3) UCERF3 Targets (mm/yr):

Zeng: 1.0-1.4; Bird: 1.2; ABM: 1.64; Geologic: 2.15;

4) UCERF3 Solution (mm/yr): 0.9 to 2.1 range; 1.4 to 1.5 mean

23

PG&E DCPP SSHAC Study

Diablo Canyon SSHAC Level 3 Study

Thank You

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