ML20052A768

From kanterella
Jump to navigation Jump to search
Discusses 771029 Site Visit Re Geologic Relationships. Geotechnical Engineer Should Be Assigned to Project Due to Possible Presence of Extremely Large & Atypical Landsildes
ML20052A768
Person / Time
Site: Vallecitos File:GEH Hitachi icon.png
Issue date: 11/07/1977
From: Rolonda Jackson
Office of Nuclear Reactor Regulation
To: Gammill W
Office of Nuclear Reactor Regulation
Shared Package
ML20052A734 List:
References
FOIA-81-483 NUDOCS 8204290146
Download: ML20052A768 (10)
v • d • e


Text

-

3

)

l

.[.. u y,ag L:t s tne t.TATES i

j i

/ *.,.

,.# ' S FRICLEAll 1:1.GlllA*e Oily C07..*lSSION

!. 8.(:' L,'fl $

wAsume,ws, o. c. 20 5s

- 2 m,.y - ;

t. i!-Qi2,/,.i l

% '.u f l

1:0Y 7 W

MD' ORA'OUM FOR:

W. P. Ga::ill, Assistant Director for Site Technology, DSE e

f ROM:

R. E. Jackson, Ccologist, Ccology and Scismology I

Se,ction, Geosciences Branch, DSE 7

J. C. Stepp, Chief, Geosciences Branch, DSE [,W-

'DIRU:

l R. B. Hofmann, Leader, Geology and Scistolofjy' t.'!$.j

  • ~ '

g Section, Cecsciences Branch, DSE

SUBJECT:

SITE VISIT - VA1.LECITOS NUCLEAR CE"TER - OCTOBER 29, 1977 On Saturday, October 29, 1977, I visited the Vallecitos site ecccc-panied by J. C. Stepp, GE consultants cnd two ACRS ccusultants. An attendance list is attached to this cero. After a sunciary introduction to the new trenching and investigntions acconplished in the past week, we procccded with a field visit.

I We re-examined trench 1 pri=arily for the benefit of thonc who had not viewed it before. Evidence for a thrust offset of a caliche-rich gravel unit over a well-deve. loped soil horizon is still obvious. At l

the north end of trench 1, a 36" calyx auger hole has been drilled to approximately 50' below the surfacc. At the 33 foot level a 1 foot shear zone was discovered. This shear zone is well developed and has rotated caliche clasts within it.

A projection of this zone to the t

trench aligns it with the green clay horizon which acts es a wetar barrier.

ESA consultants also indicated that below approximately 45-50 feet depth they encountered a large shear zone which caused extensive caving of the hole.

This latter zone would project approximately to the thrust offset observed in the trench.

f, Another trench, labeled trench 3, has been excavated across a prominent cast-vest ravine approximately 1200 feet north of trench 1.

CE consul-l tants believe this ravine may be the backscarp of a slide which gener-

.ated the thrust offset observed in trench 1.

Sand and gravel units observed in the trench dip to the north at approximately 20 degrees at the north end of the trench and approxi=ately 20 degrees south at I

the south end of the trench (see trench log number 3, attached). The central area of this trench is filled with core recent slope wash material and no structures are evident.

e 8204690 @

..... ~...

W. P. Canafil

  • I:0V y n77 We re-examined trench 2 and noted that continued drying had made rore features evident.

It appears that there is a caliche-rich gravel unit thrust over a well developed soil horizon. This offnet now seems to be generally similar to the of fset obacrved in trench 1.

Such an observation could not be made prior to this time.

A preliminary log of trench 2 has been attached to this report.

GE consultants excavated approximately 1000 fect along a ravine in=cdfately to northwest of trench 2.

This exposure revealc*the first strong evidence of landslide dcvelopacr.t that tre have seen. The observeble b'edding is overstcepened in dip relative to !.iverrore gravel units nearby and dips of cpproxi=ately 60-70 dearecs north are observed.

On airphotos, au crcuare fceture etn be obccrved at the north end of this ravinc which could be indicative of the bach-scarp of a large landslide block.

After the field visit a su==ary tecting tras held to discuss our observations. We indicated that we believed thet a conplete under-standing of the site subregion' is needed tu assess the geologic problecs of the site.

For exanple, two preminent linears can be projectcd into the immediate site area and cay relate to the proposed landslide development.

Another linear exists in the vicinity of the site pond.

This pond is apparently spring fed and may represent bedding or a possible fault surface.

We indicated that a landslide origin for the offsets observed in trench 2 appearc to be scientifically reasonabic, but further investigations are needed to confirm this.

If these offsets are gencrcted by land-sliding, relationships are likely to be extremely co= plex and exten-sive investigationswill be necessary to resolve the issue. We stated that although the thrusts observed in trenches 1 and 2 may eventually be shown to be landslide generated, this would-nat_ resolve the geologic problems at the site, in particular the issue of faulting.

The GETR s

site is located in an area of active tectonism and, as evi'denced by the recent studies, the sit'e area geology is poorly understood and

~

appears to be complex. A topographic break in slope occurs i=cediately north of the GETR site, two prominent air photo lineations pass into

,,the site area and a number of geomorphic features exist in the Vallecitos Valley: All of these are indicative of possible faulting consistent with the regional tectonism which is ongoing at a rapid rate. A resolution of the potential for faulting at the plant site vill require a determination of whether these features are fault related.

This will involve investigations in areas where possible landsliding can be discounted.

e e

^

l U. P. Ca:.m.111 '

!!DY 7 Yd7 f

j If the offr.ets observed to date are the result of landsliding, then

,1 the potential for reactivation of these slides t,ust be evaluated.

An airphoto evaluation indicates the presence of at 1 cast two recent landslides (debris flous) at the head of a prc-inent drainage which passes in clot:c proxinity.to the CETR site.

It appears that there is a potential for future debris flows along this ravine and the icpact of such an cccurrence on GETR should be evaluated.

Our understa nding of the geologic relationships in the site is evolving and we shou]d stay in close contact with the ongoing investigations.

I would sugacut that due to the complicati,ons generated at this site due to tha possibic presence of extreacly large and atypical land-slides that a geotechnical engineer be assigned to this project.

In addition, we should retain the services of a local landslide expert who is familiar with the Pleasonton, California region.

[ hi,f

$-C'R t c.

Robert E. Jackson, Geologist Ccology and Seiscology Section Ccosciences Branch Division of Site Safety and Environmental Analysis

Enclosures:

Attendance List Preliminary Log - Trench 2 Preliminary Log - Trench 3 cc v/encls:

E. Case J. Kc11cher l

H. Denton W. Burkhardt V. Stello R. Hofcann R. Cunningham R. ' Jackson W. Cammill J. Ciceves K. Coller R. Turnbull

[

A. Schwencer PDR

[

..L. Chandler Local PDR ACRS (18)

J. Scinto J. Stepp A. Berger t

9

e i

~

4 l

1 Attendance List N. Fifer General Electric D. IIarding Earth Science Associates D. Hamilton Earth Science Associates R. Jackson USNRC C. Stepp USKP.C J. Scott Fugro, Inc.

P. Davis Fu;;ro, Inc.

C. Tho:npson ACRS Consultant B. Page ACRS Consultant O

se I

e j

?

I 4

0 G

S b

e 4

e t

. ~.

..1......._...........

'".....S..

~

I 0-l

.. l j

.i.,.

i.

3

...: "n e

s t

  • <. y l

.?

.S,. :

.e

,.\\.

.s 4 ;.

1

  • t.

p e

e i

I

.s ?..

?.. 2

  • v:..'

-..g l

':'g b.

l e

s l

. e.

.s >

  • w 3

e,

/...% {

t

/..

i.f.j? *.,..

r g ;

to b

e

\\.:.

. s.. i; o

e h.g

f....

4.l i.

..s... :..

~

s y.

t s

s

\\

l I

[-. f..y

,.l I

a.. *.

g.';d...

o e

-s 8

r v.

s.t

.i e...: j g G. ;...~.

,,t

<o

  • :{* s, l. * ~ ~..,

i, " -; =

\\-

I
: i.-

s l

s..

.','.../.... :...,t

..,t.:

1-

. t.

co.

o

.,o.

.,,2,s

.*.,,. V,-

cl y..

. g. :.p K *: *

. u.h ~. A (.\\ -

,y:,

t*a

. e ;. I -)I -..:/

?,f e g.'a :

t.

?.

.?.

t-s g ra. *

.j

  • s

- s Q..*.. -

,t.

r,.

.r ).

  • e u.,..,..

gt

.. 4

.j.

.=

l

.'g e) t.. ;. $,g.p \\

'h

~.

s

. ~.

i :

et

..... ' -..?pl;.'...... :....

..V. J.*

J:. o..

)U

's. c. /

{

e s.1s..

e :/. ',i.

...t

. :),,

.e. w...:.. :y s

i v....

s

. a.. 1rs l

-.4

' ;,."_ f &y a.

.~a; a

.,.. <:.e

  • s' 13..;

t t '-

  • l**

I s

1 t?:.<f i.6. :-W. Y' '. 14,:,ll :

V !

lI

  • p 2;. A.?.;;. -

t e

s e

I

~7~fr

':.' d;:. & ' -.

  • k

?l ti s.

k t.<g:, ' ' ? )n.;Q.,* *.,.:. 7.f..?,

l

. : *

  • s'.

8

?l t

O V.

!.1 s

.e. C'.:~..

l

\\

?.

t ~'s:e.

e c

l y(

c.

g

.~.

l. s..j.n.se. t g

e :s%..> >..=c.~....

1

  • .it

.n

t. 4>,

f.,p

.s. t,,;;

s

  • p t. t.g... i s..:

. e.s,

l c.e.

.. v.;s Y.....

4 e:

s

. f r; ;...,

e s

a

  • i' l.,. / *?
  • f t l

l*

g. l [

\\

g.

y

, : y.*, it v.

.C.... s.. si' 3

s,l

. g.

..1 I

t O

g g.

,e %) '.'.'. a,8.#.

.yg2 -., ; !

. f'. i l b J

./.r

, e.

t;.

.J. st.,1,.!.f I:e.

.. j. p.

.a.

.J";.

=

< e i

s.

e we

.c

,c,...,..o'ec. ;g.'.

w.

(

g

.a

%.... ),: \\.,. -e. e,..e ' s..

e

. e... Ov.....

s

,z

.s.

s

.g

, e.

,, ; g,,,

g y

s,

g 3. v.. )... g.. S... t i -.;

g. *. g.. T

s. j.

.,s.

.s :

t}:%! -

y

.m.

8 e, ',

e*

.h

.'l l;

e

..s g.

1., k.

t.:r%.'o a

f -.,?

fx~is}

l

=

~ t 4

~

\\

t o.

k,

.ar

%g.r.,.....t. '), :.e

.s

. s.t.e

.4 :o.:. 4.*.-

l s..

.,v.,. e, s..,.

t.

. f. I,t :,r,g g ;.,s.

..6.

s.

g c.,,%.

s.. i..s.,.

.a e

.e

..",A,.,,,.c f. e. 'e s s

s,;

.i fir.-

t j j i ).

C..? ::',:3 :;. 'g i;*;;

i.j
<,: t.,i.b st

//.2: :. :(3

....... f s.t. e : ~

s:::)

c.,7..
f. ;..;

,.e. /.r 3

, n..; s.

. :.: y

. s.....

c-

& : s ;.

4 s.

l y

.n., t*.

' ;: s. :.., v, -

..a

.. w.

s,

$8-

.W.7c..l.L *

' ? i ei i-g.th:.:: '.

'I.%:: ' ! ss. :i t,1.~4' i.:eg.

. ;\\ p,..e

.e..

,. 6 A *:a it a G..*. j e.

r

.{ g t :. e..,.. !

4.]

s.

e

{
.I*qg,,

.-. s f..lf.,,

.,s f

. e

,i s

..t I

,e.

g.4., *.....g

. t % ;;+ 9y e 4,!.*. I

. a..... t... ' t

... - r Ja,,

..a F..

,,r.,e. *, e..,. f,* *);

i

m. \\.r,:, 2. % 2.e.e ll 3 } :* lm(.,w:s e

t t

f w a n-.

,e.

.s

-l, s

p

.j

n..
  • t m.

t.t, g spe w ** /. Q..-w..ff t,

s.

s w'. :

    • ..e

. v.M I.:[; s

  • ;. :.i.*

,g :

.~

e 2.4.-

h-r*

l U. 3 4 * *t.:

St:e*ElI.

. g'. r.f j.**

$"l

! 8 g

l 9

Q

  • ..l ! '.
,i U. 's'@, !' <

=

r

.i h.

' }.}'k.;,,ff. Q eg. !. ',.

l',. '

.w. ' s ;

w.

I

.. t. :. ~. s<:<

..v,,

si i, j. t.1 s.::1'.i;c.h.

I

\\

v -. e..

f...

e s #;p. i

,;.f.

J 4 e

i::

r:

[:g, ;n }' ~* s'.e

., ;.0; g.; - r.

.a ;.;

J.J..

m..

}

s i f:

g f}

a' A li

\\..

.\\.:

s 4

,-y--.-

E

.-~s, s

p *.

g

o

.............__.....___.____.__l...-._.__......

I l

f s

i n

e.99. g.:

o 4

~~..4;..;.a.%S[jl-Q s

P

?

.,',8.4 s.

..I

.{I l O o

.p.

b

.,o L,.

y.. -

.g t

f-W

.n.. J.

l d

J 3

.n..

l-

.r..

-. T -

73. - (;T...

-./

~)er-l-

..-!.'i".V-w t.

1.

I....

! I

/./-

,/

/

~$:.?

% ~ T [*{ - i, /..' 7',* : g-6j ~ (= ~.

  1. t l

i s.-).

.. f.

,f.

g

..e Z.

f, s.

q

" },~,.

g..,

f

.j e

< /.7:..g s.u.

t.

s.

l s

j. * *. ;

., )..e- - Q.)

lpj-
  • /

) A.6 :.yt.8p,;i' d ?

t b.

i c

l.. /........., l,

t

. i.,, >

l

.i./,

M.

(

s'/..'#

,.,e

'.lt

,r

.: a,/ : -

q..

.s 1

i.

J

  • . g /.

j r.

..(.

e.

o

=*

a t

f

.t.

<s

w. e p /

. h.i i

s p.

s s..

1.

,,s l s.,

. ' e.

,,g../ e,r g _s,

(..

e j

i.

8. /

.f.

/

3.f s g C../.*, g.,. -

i

=. ;.

,I t

.c

.s,

.c

.s j 1J s

I,.

.,l e.*

i

% *.;y,~-* Q W.'

78

.4 g.

t

  • -l

,.N

  1. */

s

=.Q ~ :

I -}i E

. ' k W Q,T E \\'g ' 4..i N

\\ - = = * - - ~ = -~~

l

'g -

e. -

~;'

t s

-f 1

t. '

l a'.,'s:y'/. m..e..t

~.,

..b. I s....

i t * * <.

s.

L

,p 9

r..

t...-

,. as I

.,,, / / '.f.:/.;.t.': *,,j t, f..,

8) e s

.(

s...... _...

./

., g......, /r.

.< s

,, 7 Ys.

.s,

~

I t ;.

?.x:',..i.t.h c,

I,5

1..u,;s s t;

.h

~ ---

v.

n., <

3v

.. i t..

s Q....ys

n l

n

. \\.:.,.

l $,;.',s. s.

c,

. '. r-@>

i

/.1.

t, i,.j..p,y;/e-.ya?,...r..

s.

k c..

. s, g-g

.o s

n.

s

~,. A., 1

<.3 o Es y

l v

s lli, ;f 1

/.::

. ' ' 4. $ t-

  • /

y a)s e

g, y%

... l..

i

~

. //88,.

8 (

[

. '

  • A4

.e l e m.

d. a

. =

m, e

...e_.s.--e.,.e."

(

g y

3 q p e

t.

s

=s a-t.

c.

,,,u l

i l

c.

is s.

t-

t..

. s

.?

. f.]

p.

. ' g 's J

  • t I ji i

e.

o, (l

4-ge

>l,

.g y.

t.

s o t g;i

[.

M e

. i.

)

4 a

f

'..s*

s 3

'.> t. , (

i e

s

  • b b

e

'1 ' '. l I

  • - )

4 5 ',

\\

t e.

g a

!.,) s j.

s.. '.dl

- ( 4l

%/

e e

s t

i.. ff.

g s

i *

  • t' it t y

$1 s

s r.

'.4g\\ 4 i

)

\\

s.

e g.

gn s

g

, i 1.:

Y,e

\\

3

),.

,c.r s s

r

t..

@s s

s 3

vg g,-

s.

'))

  • w i, -

i t'

i

' \\ 'i - g., i c:

i V,

e

'y

.*, y - : ;. 5 a

s i

.-s s

.sr.

t..

'. }x

.i l

t, l

n i s A

.s r;

's a

. g.1,s i

f v c i

a.:.9 4

t

,s i

s.

s..n.;

4 s.

I s '.

c.

i s e

.s :

,m v.' i;.,;-
s. t t

l e!

i

. +.. 9a4 -

i

. ('

\\

  • ~-

o.

e

~.l

.. 9,','

i i.

, i$

..e iU-1 s

s g.,.

,i -

i

.f.

.li,p,.4...s-h.g

'E u

L,'

,c, e *:: e

/

',/

~

,/S'".'.

'f~

'd I

{,ii 7.

{

e ;,k',.,'

6 e

, se e

u:

i

.I

,s. -(

e

j,.,

e*

~

e a..

1 I

e l

b s

s T. '

a'-

V

(%y'6';. M

'M iii o!

1 t

s Q.

s o

s f, **

f s

e

? g,

r s

ab I

i

.e s

ss-

\\

l sI

  • I I

t t*,

e

\\:

u'

I.

t, g /,

s, l

i i

s e

t

]4 e

~

s

.. \\.

.)

y_ Q.

tt bc.co msy i

e' s

u N2]Cr4 l Ts e nvaut ro

  • We

~

).

N'

(, *.

s,t t

st, s.

q.

\\ n,.

2 b'

01 d

r

's V :;

h l

L

~

c, s

f 4

J5 I

t,.

..s. g I

(,.

at i

.u'

... o

.u

.v.

I sr e

l

..i i,

J.,

.s$.

1 g

g t, s:.a u

. t i

t, t

~

r

~

, s,,

t. : p{ y.

V.,.

vi i

c.its i

}.

t. -

2,t.i..t.e.

')

.\\

!o lL' l '.

5 2

i

.I -

}~:.f! -. V,

.t s,*,3 t

%s

t -

s t' 4

%t,

s. g g.

1 g.,

t 7.i t.'

s o

g.

o

.i g.a n~

f i

e t

a 4

8

.i i 3

.1 g

I:n m

y m

Til t

~=

i l

. *8 hi l

e

~

4 8

e.

0 g

t.,

~

l l

g,

8 I.

j t

A$~ M/ h!&

f N s pf pq l

4p

  • y a

q o ?, m _. a 1$.*

d m e d*

d"% WM o

ll i

l s

+

/.

.I

..l e

i e

f-e (3

g w

h 8

e

{

}

i 1

0 l

e D

se

?,

6.

f 8

.e l

I k

e g

.i l

8 0

s I

.I t

.t

(

.e 4

.e e "

.8 i

j I

e e

el O

t

.ol II t

e i

.\\

y l.

L i

l e

s a

e I

b.

y gy e

e l

J

?

.e e

4 4

t. Y

...,e na i'

I 4

i I

A (e g

a g

i t

y g

g.

I:::

l s

e 4

.Ly g

y i

I!

iii r% bg e

f I,

.n -

i

  • l.t It!

,o oe a

.t'

(

1 ;.

E.

I r

! s a

/

/.

e.

)

)

N.

r I

i i

j e

i

}

.i t

/

=

... g.

l l

a-tr.d me nmn,., !

4-k

~

4l

vn

~. ' ~%

~

\\

@n cM-w n

}

s.s

,,{,j (A tt

{ :. ' & ]

[

~ j,

)

e C,;;( u

(

s

~

d\\ j*, -

t 8

at

~

y 4

~-

1 1.

y

'. l 3

o r> 5-e t } <J ss e

-)

m.)

s

\\ '

e

\\

$. ;(,vgb.

,g i

s I

{f)l',*.4i M.

t s r. ;" v s; "t

.g

.3 g

.'G _3,lf s c\\ t 1

(

i n

.\\.

s.

i.

7

.f"ir h

sl., '/*\\

p.'

I t

I:t}l' 4 !'D @' Xh !

{

1S t r

l s,.

i.

c s.-

(

s (Mw l

v 1 r }' < d i{t ~D

.(t

& ( $'t L Y._

/[Y.a.

1)1'i's.i,n'eI!:,ili, V

b fe s,l s

s a

b ';;

k-

'Q;, t, L. i

.ic %

',c:r-

!:. h

';[-; D-:.p (Ni: 4ti$:tftat

.., 1, o

.\\:

';;...,;,(

3

....,i,.

pe v.

s W l' 5, 0

k7.,* :.\\ /

s* d i F..

s, w-w, b,,e:u}{,

.ii'

( F.,

s sy u.,

t,

),.,.....e

.m: 4 s

11 i

g.>

35

~s.

r \\

g:4,ta;,it.er,,,

t

=

i

.. y

.111;3r 1: tIi f:<

a

=

(r i

t Mt

( a s 4 4.

  • t l t 4 (

lii

,e

)

4 e

f 4

4 8

9 e

M e

e' J

38

.4 J.-te d of M r>

m,,,,,,4 4>

?.'f.

~

~

c=o f

.2%.wwr1 29

Retrieved from "https://kanterella.com/w/index.php?title=ML20052A768&oldid=4512396"