ML20281A409

ISFSI, Revision 10 to the Updated Final Safety Analysis Report, Figures 2.6-86 to 2.6-120

ML20281A409
Person / Time
Site:	Humboldt Bay
Issue date:	09/03/2020
From:	Pacific Gas & Electric Co
To:	Office of Nuclear Material Safety and Safeguards, NRC/OCM
References
HIL-20-005
Download: ML20281A409 (35)

Text

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-86 Diagrams illustrating progression of tsunamis at the coast, and stratigraphic columns in the quiet water of bays and ponds.

Revision 0 January 2006 Drawdown of tsunami waters, scour, and reworking of tsunami sand and debris Tsunami waters recede from coast; erosion along channels and other places, and debris deposits mark the maximum runup Maximum tsunami flood deposition Tsunami reaches maximum runup, water quiets, and sand and debris settle Pre-tsunami conditions R elatively quiet water; normal accumulation of mud, sand, and organic matter Tsunami runup, entrainment and transport Tsunami overtops sand spit, crosses bay and reached the coast, transporting sand and debris into the bay Tsunami sand settles and is deposited as thin layer S and and debris in suspension Present marsh Paleotsunami sand Buried marsh S and and debris in suspension S and and debris settles New deposit of tsunami sand Area of erosion Tsunami sand eroded and reworked by receding water III IV I

II

E ureka FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-87

North Spit, Humboldt Bay (foreground), and Arcata Bay (background). View is to the north from above the bay entrance. The Mad River Slough is located in the marshland on the north side of Arcata Bay. The Humboldt Bay Power Plant is just out of the picture to the lower right.

U.S. Coas t Guard S tation Mad R iver S lough Revision 0 January 2006

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-88 COASTAL SITES INVESTIGATED FOR EVIDENCE OF PALEOTSUNAMIS IN NORTHWESTERN CALIFORNIA Revision 0 January 2006 0

30 km 0

20 mi OR E GON CALIFONIA Cres cent City Lagoon High Prairie Creek E as t Major Orick B ig Point S t. George Patricks Point Cape Mendocino North R ailroad S outh Hookton S lough Mad R iver S lough Humboldt B ay National Wildlife R efuge S ee Figure 2.6-114 for details C

h e

t c

o R

i v

e r

Sm ith Rive r

K l

a m

a t

h R

iv e

r Redw oo d

Cre ek M

a d

Rive r

Ri v

e r

E e

l Bear R

i v

e r

M a

t t

o l

e Riv er J acoby Creek Mars h E ureka Humboldt B ay Power Cascadia Subdu c

t i

on Zone Little Salmon Fault Zone E XPLANATION S ite having evidence of tsunamis S ite having no evidence of tsunamis P A C I F I C O C E A N N

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-89

Cross section of a typical intertidal marsh. Figure shows the idealized relationship between tsunami sand deposits and stratigraphic and biostratigraphic features caused by coseismic subsidence. The key to the numbers is shown in Table 2.6-23.

Revision 0 January 2006 High marsh Low marsh S and dunes Mud flat

High marsh Low marsh Channel 1

2 3

6 9

10 19 24 12 18 13 8

11 Lithologies Low marsh High marsh S and Mud Contacts S harp Parting E rosive Gradational S ymbols Marsh plant R ip-up clast Bivalves LM Low marsh diatoms MF Mud flat diatoms (Modified from Carver and others, 1998)

LM LM LM MF MF

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-90

Cross section of a typical coastal freshwater marsh. Figure shows an idealized tsunami sand layer interbedded with peat and mud. The key to the numbers is shown in Table 2.6-23.

Revision 0 January 2006 4

4 6

6 7

4 4

16 5

8 9

7 5

16 17 17 18 19 20 21 18 22 23 24 22 23 24 24 24 9

10 11 12 11 12 9

13 14 15 15 8

Lithologies Contacts Peat S and Mud Diamicton S harp Parting E rosive Gradational S ymbols S pruce cone S tick Twig R ip-up clast Freshwater diatoms Wood chunk Brackish-marine diatoms "Flopover" Leaf (From Carver and others, 1998)

This example is based on the W layer in core CC-1 from the Crescent City marsh.

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-91 IDEALIZED DETAILED SECTION SHOWING MULTIPLE GRADED SANDS IN A TSUNAMI DEPOSIT Revision 0 January 2006 (From Carver and others, 1998)

Depth (cm)

Material Diatoms Interpretation 90 100 110 120 130 Peat Peat Muddy Peat Mud Wood, twigs Approximately 12 layers, some graded, interbedded thin mud layers with Carix sp.

flopovers Peat S and S and CC-1 F

F, F-B, B-M, M F

F, F-B F, F-B, B-M, M F, F-B, B-M, M F, F-B, B-M, M F, F-B, M F, F-B, M F, F-B, B-M, M Interseismic Distant tsunamis Interseismic Postseismic disturbance Tsunami debris Local tsunami deposit showing wave pulse sand layers alternating with washback mud layers F

F-B B-M M

- Freshwater

- Freshwater to brackish

- Brackish to marine

- Marine

Gouge coring at Crescent City marsh. Hans Abramson, collecting a gouge core in the marsh, is employing a typical technique for obtaining a reconnaissance core.

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-92 Revision 0 January 2006

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-93 TYPICAL GOUGE CORE. THE FINGER POINTS TO A THIN LAYER OF FINE-GRAINED TSUNAMI SAND, WHICH IS INTERBEDDED WITH MARCH PEAT Revision 0 January 2006

Drilling using the Vibracore at Lagoon Creek.

The 3-inch-diameter core tube is shown in position before being driven into marsh sediments.

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-94 Revision 0 January 2006

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-95 TYPICAL DRIVE CORES.

THE TWO SPLIT-SAMPLE TUBES SHOW TSUNAMI SANDS (ARROWS) IN CORES FROM THE ORICK MARSH Revision 0 January 2006

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-96

Comparison of ages for Cascadia earthquakes from tsunami data between northern California and Washington. Width of lines showing Cascadia events ("Y", "W", "U", "S", "N", "L", and "J" ) from Kelsey and others, 2002).

Y W

U S

L J

N Crescent City, Orick, Lagoon Creek and S outh Bay data from Carver and others (1998); Washington data from Atwater and Hempill-Haley (1997);

Hookton slough data from Patton and others, (2002); and Oregon data from Kelsey and others (2002).

Closely limiting age range-Measured on detritus within or at top of sand layer Limiting minimum age range-Measured on plant material above sand layer Limiting maximum age range-Measured on plant material below sand layer 23

1. of samples used to estimate the most likely age range for each event in Washington S tate Key

• This age, from a small seed interpreted to be reworked into sand layer S, is not considered to be a closely limiting age for the horizon Cres cent Lagoon Oric South Approximate age, in calibrated radiocarbon years before 1950 0

1000 2000 3000 4000 Y

W Q

U S

N L

Y W

U N

S L

L Y

Y Y

Y W

W U

U U

S L

J J

N N

N S

S S

L L

L J

E VE NT C

D E

27 5

3 2

2 2

2 3

3 4

5 5

2 7

23 9

12 Washington State Sixes River Coquille Estuary Hookton Slough 5

S outhern Oregon Northern California Revision 0 January 2006

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-97 LOCATION OF CORES IN CRESCENT CITY MARSH Revision 0 January 2006

Crescent City Marsh S ite FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-98 CRESCENT CITY VIEW TO WEST Revision 0 January 2006

Cres cent City Mars h s ite Cres cent City Mars h s ite Cres cent City Mars h s ite FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-99 CRESCENT CITY MARSH Revision 0 January 2006

Capital letters ("Y ", "W", "U", "S", "N" and "L") designate sand layers correlated to dated Cascadia subduction zone earthquakes, queried layers are uncorrelated sand layers interpreted to be of Cascadia origin, arrows indicate sand layers from distant-source tsunamis. BP dates refer to calibrated radiocarbon years before 1950. "Q" is a local event intermediate between "Y " and "W".

(From Carver and others, 1998)

Q FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-100 CORRELATION OF TSUNAMI SANDS IN SELECTED CORES ACROSS CRESCENT CITY MARSH Revision 0 January 2006 CC-1 CCVB -14 CCVB -1 CCVB -3 CCVB -5 CCVB -6 CCVB -8 CCVB -9 West E ast 150

Location of cores in the Lagoon Creek marsh. Map shows topography, bathymetry (dashed contours) and vibracore locations.

Cross section A-A' is shown on Figure 2.6-105.

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-101 Revision 0 January 2006 9

13 10 19 20 21 3

2 1

8 7

4 6

5 15 14 16 11 7

12 18 BE ACH 40 120 80 120 160 80 40 80 120 160 200 280 240 US 101 A

A' N

P A C I F I C O C E A N 0

0 500 m 1000 ft.

Contour interval 40' (12.2 m); Bathymetry interval 1 41°36' 124°06' U.

S.

1 0

1 41°32' 30" 124° 05' False Klamath Cove Lagoon Creek 0

1 km (From Carver and others, 1998; Garrison-Laney, 1998)

The Lagoon Creek pond and marsh. View is to the south, showing the beach ridge, pond, and marsh in this narrow valley. Tsunami sand layers were found in the marsh sediments inland to the upper end of the marsh visible in this photograph.

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-102 Revision 0 January 2006

R edwood Creek Valley Lagoon Creek Wilson Creek Wilson Creek and Lagoon Creek. Wilson creek during the Pleistocene flowed around where the sea bluffs are today and down Lagoon Creek to Redwood Creek. Sea erosion has cut off Lagoon Creek from Wilson Creek, leaving Lagoon Creek as a stable site undisturbed by stream erosion.

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-103 Revision 0 January 2006

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-104 BEACH BERM AT LAGOON CREEK 23-FEET ABOVE MLLW. VIEW IS TO THE NORTH FROM THE NORTHERN PART OF THE LAGOON CREEK MARSH Revision 0 January 2006

(From Carver and others, 1998; Garrison-Laney, 1998)

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-105 CORRELATION OF TSUNAMI SANDS IN SELECTED CORES ACROSS LAGOON CREEK MARSH. THE LOCATION OF CROSS SECTION A-A' IS SHOWN IN FIGURE 2.6-101 Revision 0 January 2006 1400-1720 BP 1290 1550 BP 980-1300 BP W

U S

N Y

W U

S Y

970-1290 BP 1270-1520 BP 910-1300 BP 2340-2760 BP 3060-3470 BP W

U Y

W U

Y W

U S

W S

1060-1330 BP 1290-1710 BP 270-560 BP 1260-1530 BP 2790-3210 BP 1050-1300 BP 2890-3370 BP*

1280-1520 BP 1160-1350 BP 1280-1520 BP 1510-1820 BP S and Other deposits Water BP dates refer to calibrated radiocarbon years before 1950. Asterix (*)

indicates age is from a small seed interpreted to be reworked into the sand layers and is not considered to be a closely limiting age for the horizon "Y" "W", "U", "S ", "N" and "L" are events from Cascadia earthquakes 2890-3570 E XPLANATION LAGOON CR E E K 0

1 2

3 4

5 Depth (meters) 18 16 4

9 21 3

2 283 m 35 m 169 m 257 m 69 m 39 m North S outh A

A' L

(From Garrison-Laney, 1998)

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-106 DETAILED STRATIGRAPHY OF CORE LC-16 FROM THE LAGOON CREEK MARSH.

DIAGRAM SHOWS TYPICAL MARSH, SAND DEPOSITS AND DIATOMS NEAR THE COAST Revision 0 January 2006 low med c

c c

f 1540-1290 1330-930 2780-2360 3540-3120 cm 0 50 100 150 200 250 300 350 f

f m

ru p

p m,ru p

m p

p,ru m

m f

1300-1060 0-550 0

20 40 60 80%

0 20 40 60 80 100%

0 1

2 3

4 5

6%

Abrupt ( 1 mm)

S harp (1-3 mm)

Gradational (4-10 mm)

Diffuse (11-20 mm)

Diffuse ( 50 mm)

CONTACTS AND SYMBOLS DIATOM PRESERVATION Very good to excellent Fair to poor Moderate stick twig spruce cone roots sand tunnel d detritus ru rip-ups leaves wood chunks charcoal s sandy m muddy p peaty c coarse f fine Lithologic Modifiers Lithologies peat muddy peat peaty mud mud sand LITHOFACIES CODES Quantity Broken Diatom Preservation 1/3 2/3 Calibrated radiocarbon years before 1950

% Brackish-Marine Diatoms

% Marine Beach Diatoms CORE LC-16 Freshwater Diatoms Y

W U

S N

L Cascadia Event

(From Garrison-Laney, 1998)

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-107 DETAILED STRATIGRAPHY OF CORE LC-2 FROM THE LAGOON CREEK MARSH.

DIAGRAMS SHOW TYPICAL MARSH, SAND DEPOSITS AND DIATOMS NEAR THE COAST Revision 0 January 2006 Quantity B roken Diatom Preservation

% Brackish-Marine Diatoms

% Marine Beach Diatoms CORE LC-2 Freshwater Diatoms 0

50 100 150 200 c,p f

c p

c c

m m

p 1870-1540 m

m f

s low med 0

10 20 30%

0 20 40 60 80 100%

0.00 Y

W U?

S N?

0.20 0.40 0.60

%.80 1/3 2/3 Abrupt ( 1 mm)

S harp (1-3 mm)

Gradational (4-10 mm)

Diffuse (11-20 mm)

Diffuse ( 50 mm)

CONTACTS AND SYMBOLS stick twig spruce cone roots sand tunnel d detritus ru rip-ups leaves wood chunks charcoal s sandy m muddy p peaty c coarse f fine Lithologic Modifiers Lithologies peat muddy peat peaty mud mud sand LITHOFACIES CODES Calibrated radiocarbon years before 1950 DIATOM PRESERVATION Very good to excellent Fair to poor Moderate Cascadia Event

Townsite of Orekw (Oreck) and location of cores in Orick marsh.

Map shows the village Orekw, the site of Tskerkr's oral history, A Flood (Kroeber, 1976; Carver and Carver, 1996). Also shown is Ida's house site, where floodwaters came to "the front door." Both stories document flooding to about 66 and 69 feet elevation (MLLW). The cores from the Orick marsh record the "Y," as well as earlier tsunami intrusions, and one later tsunami.

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-108 Revision 0 January 2006 20 20 404' 693' Idas House Idas S tory 66 ft. (MLLW)

Otmekwor R edwood National Park Visitors Center S iwits u Orekw US 101 20 Tskerkrs S tory 69 ft. (MLLW)

Core O-Core O-N P A C I F I C O C E A N Redwood Creek Freshwater Lagoon 0

300 m Contour interval 40' (12.2 m) 0 1000 ft 500

Orick Townsite Orick Marsh FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-109 TOWNSITE OF ORICK AND THE ORICK MARSH AT THE MOUTH OF REDWOOD CREEK (ON LEFT SIDE OF PHOTO). THE TOWN WAS BUILT ON THE HILLSLOPE ABOVE THE BEACH AND MARSH Revision 0 January 2006

Revision 0 January 2006 FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-110 GEOMORPHOLOGY OF THE NORTH AND SOUTH SPITS OF HUMBOLDT BAY E ureka S amoa Humboldt B ay Power Plant X 25 X 20 X 30 X 40 X 40 X 40 X 20 NOR TH S PIT SOUTH SPIT P A C I F I C O C E A N HUMBOLDT BAY 1854 Bay E ntrance X 19 X 17 X 20 X 10 X16 E ureka City Airport BE ACH R IDGE S Indian Island North Jetty S outh Jetty E

l k

R i

v e

r N

Arcata Bay South Bay X 40 Active sand and developed areas S outh S pit pre-jetty dunes S outh S pit beach sequence Intermediate dune sequence Marsh E levation (feet)

E XPLANATION 0

4 km 0

2 mi (From Leroy, 1999)

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-111 SOUTH SPIT.

VIEW LOOKING NORTH FROM TABLE BLUFF.

SOUTHWESTERN HUMBOLDT BAY (SOUTH BAY)

MARSH SITE IS IN MIDDLE RIGHT OF PHOTO Revision 0 January 2006

S outh Bay S ite Hookton S lough S ite Tompkins Hill FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-112 MOUTH OF HUMBOLDT BAY AND THE SOUTH BAY HOOKTON SLOUGH SITES.

SOUTH BAY IS SEPARATED FROM EEL RIVER VALLEY BY TOMPKINS HILL AND TABLE BLUFF Revision 0 January 2006

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-113 LAG PEBBLES AT EL. 27 FEET (MLLW) ON THE SAND DUNES ON THE NORTH SPIT BELIEVED TO BE DEPOSITED BY A TSUNAMI THAT INUNDATED THE DUNES Revision 0 January 2006

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-114 MAP OF THE NORTH SPIT SITE, SOUTH BAY, AND OTHER HUMBOLDT BAY MARSH SITES Revision 0 January 2006 Ma d

R i

ver Sl o

u g

h NOR TH S PIT S OUTH S PIT E ureka R ailroad Hookton S lough North S pit HBNWR Humbolt Bay National Wildlife R efuge E ureka S lough Jacoby Creek Marsh Mad R iver S lough S amoa Arcata Tyee City Humboldt B ay Power Plant Area of S outh B ay N

P A C I F I C O C E A N Arcata Bay South Bay HUMBOLDT BAY E XPLANATION S ite having evidence of tsunamis S ite having no evidence of tsunamis S outh Bay PACIFIC OCEAN l

l l

l l

l l

l l

l l

l l

l l

l l

l l

l l

l l

l l

l l

l l

l l

l l

l l

l l

l l

l l

l l

l 1 2 3 4 5

7 6

10 9

8 S outh Bay core sites S outh Jetty R oad MARSH S outh S pit Levee 0

0 3 mi 5 km S outh B ay S ite

S outh Bay S ite FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-115 SOUTH BAY SITE.

TABLE BLUFF IN THE MIDDLE OF THE PHOTO SEPARATES THE EEL RIVER VALLEY IN THE MIDDLE DISTANCE FROM SOUTH BAY ON THE LEFT Revision 0 January 2006

FIGURE 2.6-116 Correlation of tsunami sands in selected cores across the South Bay marsh.

Revision 0 January 2006 SAFETY ANALYSIS REPORT HUMBOLDT BAY ISFSI S B VB -2 S B VB -8 S B VB -4 S B VB -5 S B VB -6 S B VB -10 0

1 2

3 Depth (meters)

Lithologic Modifiers and Symbols Lithologies Diatom Samples Contacts BP dates refer to calibrated radiocarbon years before present.

(From Carver and others, 1998)

"Y" and "S " are events from Cascadia E arthquakes (Figure 2.6-96)

Preliminary Survey of Humboldt Bay, California, U.S. Coast Survey, 1858 (edition of 1879), (original scale 1:30,000) (aids to navigation corrected to 1885). Depths are in feet below mean lower low water to lowest dotted line, then in fathoms. Red line delineates present shoreline and jetties from USGS Fields Landing 7.5 minute Quadrangle (1989). Brown area is plant site.

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-117 PRESENT COASTLINE SUPERIMPOSED ON THE 1858 MAP OF MOUTH OF HUMBOLDT BAY Revision 0 January 2006 0

0.5 mi 0

0.5 km Plant site IS FS I S ite

Soundings are in sazhens (Dr. Lydia Black, personal communication, 2001) (1 sazhen is about 7 feet); numbers in parentheses in the entrance channel clarify the original sounding. Original map in Golovnin, Vasili, undated, Voyage of Kamchatka and maps which accompany - Russian ed., Alaska State Historical Library, Juneau, Alaska FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-118 THE 1806 MAP OF HUMBOLDT BAY (BAY OF REZANOV) MADE BY RUSSIAN EXPLORERS Revision 0 January 2006

FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-119 PLOT OF MOMENT MAGNITUDE VERSUS AVERAGE MAXIMUM TSUNAMI RUNUP FOR THE BETTER-DOCUMENTED TSUNAMIGENIC EARTHQUAKES Revision 0 January 2006 100 50 10 1

7.0 7.5 8.0 8.5 9.0 9.5 5

10 E arthquake magnitude Maximum near-source tsunami runup (meters)

Maximum near-source tsunami runup (feet) 2 20 30 60 70 80 90 100 200 300 40 50 18 14 13 12 5

3 6

4 7

2 1

1979 Colombia 1964 Alaska 1991 Costa R ica 15 11 11 10 9

17 16 19 1994 Java 1993 Hokkaido 1993 Flores Is.

1995 Mindoro 1992 Nicaragua GR OUP GR OUP 17 8

1946 Aleutian Tsunamigenic earthquake Major continental margin earthquake Cascadia earthquake S low earthquake Known or inferred landslide-generated wave runup associated with a tsunamigenic earthquake E arthquake in which tsunami is generated by submarine landslides E XPLANATION 1960 Chile Cascadia earthquake

Dunes MLLW MLLW E ast end +24 West end +75 MLLW Mean sea level MHHW

+6.9

+3.7

+5-6

+12 Buhne Point

-25

+23

+5-6 Marsh on east side of Buhne Point Vertical exaggeration 40x Maximum runup at entrance to Humboldt Bay (estimated from studies of paleotsunamis along coast 30 to 40 feet above MLLW and 37 to 47 MHHW)

Notes:

1. MLLW is reference for bathymetry and topography at Humboldt Bay Power Plant and IS FS I sites.

0 50 100

-50 E levation at yard +12, (all surveys referenced to MLLW)

E s timated Maximum R unup at Plant S ite (Tables 2.6-26 and 2.6-28)

Paleotsunami (attenuated)

Lamberson and others, 1998 Bernard and others, 1994 PG&E, 1985 (Houston and Garcia)

PG&E, 1985 (Brandsma)

Wiegel (PG&E, 1966)

Meyers and others (1999)

E mpirical 8.8 Cascadia event E XPLANATION R ange of tsunami runups between MLLW and MHHW Maximum runup estimate Minimum runup estimate True scale Feet S outh spit Northwest S outheast Channel Buhne Point Plant S ite IS FS I S ite IS FS I S ite Inlet channel 200 0

-200 FSAR UPDATE HUMBOLDT BAY ISFSI FIGURE 2.6-120 SCHEMATIC DIAGRAM SHOWING ESTIMATED TSUNAMI RUNUP HEIGHTS AT THE HUMBOLDT BAY ISFSI SITE Revision 0 January 2006