ML20071D838

Seismic Activity Near VC Summer Nuclear Station,Jul-Sept 1982

ML20071D838
Person / Time
Site:	Summer
Issue date:	09/30/1982
From:	Talwani P SOUTH CAROLINA, UNIV. OF, COLUMBIA, SC
To:
Shared Package
ML20071D832	List: ML20071D828 ML20071D838
References
82-3, NUDOCS 8303110343
Download: ML20071D838 (20)

Text

.

TECHNICAL REPORT 82-3 SEISMIC ACTIVITY NEAR THE V.C. SUMMER NUCLEAR STATION For the Period July - September 1982 i

by Pradeep Taiwani Principal Investigator Geology Department University of South Carolina Columbia, S.C. 29208 Contract No. N301315 DR DO K c5

s Technical Report 82-3

{ .

e-SEISMIC ACTIVITY NEAR THE V. C. SUMMER NUCLEAR STATION i

For the Period 4

July - September 1982 l

by Pradeep Talwani Principal Investigator

. Geology Department i'

University of South Carolina Columbia, S.C. 29208 Contract No. N230519 I

1 INTRODUCTION This report presents a sumary of seismic activity near the V. C. Summer Nuclear Power Station in South Carolina for the three month period between July 1 and September 30, 1982. During this reporting period a total of 63 locatable events were recorded. The largest events were of magnitudes between 1.0 and 2.0 and are listed in Table 1.

SEISMIC NETWORK The report is based on the data recorded by a four-station network operated by S.C.E. and G. In addition, data from a permanent station (JSC) of the South Carolina seismographic networl: is also used.

Location of all these stations is shown in Figure 1, and their coor-dinates are listed in Appendix I.

DATA ANALYSIS

. Location of the events is determined using HYP071 program (Lee and Lahr, 1972) and the velocity model given'in Appendix II. The event magnitude (M t

) is determined from signal duration at Station JSC, using the following relation:

Mg = -1.83 + 2.04 Log D where D is the signal duration (seconds).

An estimate of daily energy release is determined using a simplified magnitude (M L

) energy (E) relation by Gutenberg and Richter,1956.

log 10E = 11.8 + 1.5 ML RESULTS The 63 locatable events recorded during this reporting period (July 1 - September 30, 1982) are listed in Appendix III. Five events had

2 TABLE 1 Date Magnitude July 29 1.42 July 29 1.12 July 30 1.15 August 27 1.32 September 18 1,44 I

1 4

3 magnitudes between 1.0 and 2.0 and the rest were small (ML < l .0).

Their depth estimates indicate that 35% of the activity during this period occurred below 2.0 km depth, the deepest event being 4.7 km deep. How-ever, in the past, relocation of these events with magnetic tape data suggests that these may be shallower than the true depths.

A sequence of 14 events occurred near Newberry, S.C., about 25 km west of the V. C. Summer station, in July and August. The main event (ML = 2.3) occurred July 16 and was followed by eight smaller shocks between July 16 and July 22, and five on August 12 and 13. (See also Robinson et al., 1982.)

A cumulative plot of the epicenters of the events located during this reporting period is shown in Figure 2. A cross section along the line AA' (Fig. 2) 48 0NW including events within 0.5 km of the line is shown in Figure 3. The hypocentral locations are shallower below the Monticello Reservoir than outside it. The clusters of activity do not appear to define any fault plane. A monthly breakup of their locations is shown in Figures 4-6.

RESERV0IR WATER LEVEL AND ITS COMPARISON WITH SEISMICITY Monticello Reservoir is a pumped storage facility. Any decrease in reservoir level associated with power generation is recovered when water is pumped back into the reservoir. There can be variations up to about 4 feet per day between the maximum and minimum water level. We have been monitoring this water level to see if there is any correlation between the daily or seasonal changes in the reservoir level and the local seismicity.

Figure 7 shows the comparison of water level to seismicity. The top two graphs show the water level and the change of water level per day. The

4 number of events per day and log of energy released per day are shown on

the lower two graphs. The histograms showing events per day and log of energy release, include the unlocated events around the reservoir. i CONCLUSIONS j This reporting period, July 1 through September 30,1982, is characterized by a low level of seismic activity. Figure 8 shows a histogram of the number of events per month from December,1977 through September,1982, which suggests a long term seismic trend at Monticello

Reservoir of discrete earthquake swarms separated by relatively quiet periods. The low level of seismicity for this three month period is in agreement with the long term trend in that it follows the large swarm that occurred during the previous reporting period.

4 l

REFERENCES Gutenberg, B. and Richter, C. F. (1956). Magnitude and energy of earthquakes, Ann. Geof. 9, p.1-15.

Lee, W. H. K. and Lahr, J. C. (1972). A computer program for determining

, hypocenter, magnitude and first motion pattern of local carthquakes,

, Revisions of HYP0 71, U.S.G.S. Open-File Report,100 pp.

Robinson, A. W., Rawlins, J. and Talwani, P. (1982). The Newberry County, '

S.C., earthquakes of July and August,1982, Earthquake Notel,

v. 53, no. 3, p. 33.

l l

\ -

l l

,,,...c _

.,_,_.-_.,,_r..r-----n- ,c-

5 Il 4

MONTICELLO RESERVOIR A

y JIM O

^JSC STUDY AREA a

SOUTif 'a t,Ot s t'i A 0 SKM -

2 Figure 1

6 MONTICELLO EARTHOUAKES JULY - SEPTEMBER 1982 R. O 21.0 30.0 19.0 38.0 37.0 . 15.0 81

• 1 I I I i i 1 I i i i i i 1

- 25.b

_ .23.5

.23.0

_' O .22.5 1

O

_ 22.O

_21.5 8

_ _21.0 l

j ,

a _ma.s

, , 3m . _20.0 Q E3

• e

- 19.0

_ e

• 15.5

, _ 10.0 i

[ _ _ 17.5

_} _ sv.o 16.5 p,

_ 15.0 l _ 1s.5 i i i i i i i i i i e i i i 34 "

l l 0 KILUMETERS 5 l

l 1 i l I i e a a Bl0 C 8 G Al+ X o

-3 0 3 2 3 5 5 0 8 2 3 4 5 3 MAGNITUDE DEPTH (KM)

I l Figure 2 l

l i

7 R 9,

.. .r

+ +

1. 0 . +

++

t. e +

e

+ + +

5 2

s.o .

S + .

5 s.o .

+

5. 0 ,

. e. 0 .

Figure 3

8

~

MONTICELLO EARTHOUAKES JULY 1982 22.0 21.D 20.5 te.s 3s.0 37.0 . 35.0 26.0 23.5 23.0 l 22.5 0

22.0

' fi.5 21.0

- ** 20.5 20.0 cp 19.0

, F,, % . . i...

-. T' k' . e.o 17.5 11.0

- D ,...

35.0 15.5 I I I I I I I I I 3 11 "

I I I I i 0 KILOMETEMS 5 t l l t I e

- a e e 0 0 e o a + x o

-3 0 3 2 3 4 5 d 1 2 3 4 5 E MAGNITUDE DEPTH (KP)

Figure 4 w_

9 MONTICELLO EARTHOUAKES AUGUST 1982 32.0 21.0 30.0 40.0 10.0 37.5 , 18.0 81 "

1 I i 1 I f f I f I f i 1 I

.. _2s.D

- _ ts.5

- _23.0 t

- _ st.s

- _ 22.0

_et.s

- += _at.o

.. 20.5

• a, _ so.o

-/ ,e _ is.s

- _ Is.o l \ .1's. 5

_ _ 17.0

_ _is.s

- _ts.O

_ 15.5 i e i i i i i i i < i i i 0 KILOMETERS 5

. I i 1 i  ! J l e e [D L5 e O ^ + X oj

-1 O I 2 3 4 5 0 1 2 3 *J 5 E Mr.CNITUDE DEPTH (KHI Figure 5

10 MONTICELLO EARTHOUAKES SEPTEMBER 1982 22.5 21.0 30.5 t9.0 15.0 37.0 .15.0

- _es.o 23.5

- . 23.o

- _ 22.5

- _22.5

- 21.5

- 25.0 j _20.5 6,

. . . _20.o

-l

-i _ 19.S

_ 19.0

- 18.5

- 10.0

- 17.5

- 17.0

- 16.5

_16.0

_. 15.5 i i i i i I i i I i i i i i 0 KILOMETERS 5 I I I i I i

= = 0 O DO O O A + X e

-1 0 3 2 3 5 5 0 1 2 3 4 5 4 MAGNITUDE DEPTH (KM)

Figurc 6

11 no.a.

C "l?

• W zw u g" S25. C.

E o W

• e i i i a i i . i 82.232 82.242 82.252 82.262 82.,12 82.182 32.192 82.202 82.212 82.222 JULIAN DATE S...

_, p ww k

> LL) 11111. \ [

2.5 . k/

Cw \1 w t.o D-- Z CC 3 T. g u <

S.,

St.l., S,:,oi .,:m sm .:2,, .,:m .,:2,, .,:m 2,:m 82.3 2

• JULIAN DATE g ... .

C LL)

Z W

15.0 . -

1 . ._

.... Ini lf e i r

i fl lh.

82.242 I.m 82.252 02.262 i

62.272 32.182 82.192 82.202 32.232 82.222 M.232 JULIAN DATE y) 80.0 .

6--

Z -

R&l 113 Lt S.8 .

D .

C y . . .. . . . .. . .

0.0 82.202 Ss.212 82.222 82.232 82.242 8 .252 82.262 82.2?2 82.182 S .192 JULIAN DATE Figure 7

,. l~

N e 8 9

1 2

I $

y 1 8

L 9

1

_ I 0

_ 8

_ 9

, 1, f-I

_ s e 9 7

9 1

I 8

• - 7

- 9 1

/l - .

. // -

i h 7

_ fr . .

4 7 0 0 0 9 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 6 8 7 6 5 4 3 2 1 1

e.c*>w_o.oz o

i

APPENDICu -

e

i 4

APPENDIX I STATION LOCATION NO. STN. LAT. N. LONG. W.

1 001 340 19.91' 81017.74' 2 002 340 11.58' 81 13.81' 3 003 3a021.09' 81027.41' l 4 004 340 25.72' 81012.99' 5 JSC 34 16.80' 81015.60'

6 008 34 24.53' 81 24.55' i

i l

, , . . , .. - . _ - - . . ~ . . . . . , - . . - . . . _ , , _ - - . - . . , . - - - . , . - - . _ - - _ . - - - - _ . . _ _ . . . . , - -

t' d

i 1 .

l APPENDIX II MONTICELLO RESERVOIR VELOCITY MODEL

! Velocity Depth km/sec km 1.00 0.00 5.40 0.03

5.90 0.18 6.10 0.46

, 6.30 0.82 8.10 30.00 I

\

l 4

l I

- . . ~ , , . - . , - . - . - - . - ,#- - _ ,,,,, ,,ev.,m,e, .. - - - , . . . . . _ . ,_ y .-,,, - - , - . , , . _ - . , , . - - < - . , . , . . - -

e e

APPENDIX III r

1 l-i l

l I

e l

l l

l l

MOHTICELLO EARTHQUAKES JULY - SEPTEMMER 1982 DATE 1RIGIN LAT N LONG a UEPTH MAG NO GAP OMIN RMS ERH ERZ M 820708 033 55.82 34-19.52 61-18.80 3,03 -0.24 6 262 1 0.04 0.7 0 8 0708 548 35.64 4-18.40 81-18.95 1.34 -0.24 7 203 384 0.09 0.7 2,.4

8 070A 651 1.69 4-17.97 81-18.95 1.85 -0.60 212 4.0 0.08 0.7 1 656 22.43 4-19.33 8 0708 1.85 -0.66 190 2.6 0.07 81-19 0.4 1 8 0708 8 0708 8'4 8 1 .07 4-18.45 81-19 2h 81-17 0M 1.90 -0.60 204 3.4 0.08

-0.86 5 234 2.6 0.09 0.6 1.1 03

1. 1 8 0708 848 3 .39 34-18.51 1 9955 0 1 8 206 3.6 0.07 13 1 849 . 01-19 91 14 1. 0.5 1.0 1

8 0708 853 3 .29 35 34-18.38 34-1A.3Q 81-1 . 55 0.56 0 9 8 212 4.1 0.08 0.5 1.4 1 8 0708 854 1 .08 34-18.40 81-1 .%b 1.43 -0. 6 6 243 2.7 0.08 0.6 0.9 1 8 0708 M56 1 .17 34-18.56 81-1 31 0.12 -0.60 5 204 2.6 0.06 0.6 1.3 1 39 34 0.09 0.01 8 178 2.9 0.08 0.5 1.0 61 8 0708 0708172~0 1523 35.82 7.36 3rl-14 34-19 32 81-17 81-18 52 1.34 -0.40 9 130 1.6 0.03 0.1 0.3 81 8 0708 1917 12.66 34-19.53 81-18.89 1.60 -0.60 5 246 1.9 0.05 1.5 0.9 C1 8 0708 20 2 44.87 34-20.55 81-16.63 2. 7 0.21 9 224 2.1 0.02 0.2 2 C1 820709 239 46.11 34-18.84 81-17.68 1. 1 -1.22 7 146 2.0 0.05 3 0

0. 5 81 820709 1522 32.36 34-18.28 84 81-17 50

0. 5 -0.40 6 234 3.0 0.06 03

1. 1 0 .0 9 C1 820710 334 12.13 34-19.16 81-18 1.00 -1.83 3 355 1.8 0.01 0.0 8 0711 547 2.98 34-le.44 81-22.25 2.65 -0.60 6 236 7.4 0.04 0.4 1.6 C1 8 0713 to 6 57.69 34-10.72 81-17.84 0.07 0 7 163 0.4 0.06 0.7 0.5 1 8 0713 1073 3.95 34-10.50 15 1.00 -0 07 75 3 355 1.0 0.02 0.0 0.0 1 820714 449 54.03 34-23.13 81-18 81-1M.71 2.69 20 7 167 6.1 0.05 0.2 1.0 1 8?0715 1712 53.56 34-19.26 81-19.19 -0 86 5 249 2.5 0.06 0.37 -0 0.4 0.3 C1 640718 177 12.92 34-20.84 Mi-20.80 1.38 -0, 24 10 173 5.1 0.06 0 1.7 1 2014 8 81-1A.47 1.80 0.73 to 135 6.1 0.06 0. 1 9 1578 5 67 9 20a0 38 84 34-23.164-19.59 4-19.93 81-33.54 81-32.08 1.97 1.98 1.42 9 3uo 1.12 9 295 4 5 0.06 8 0.05 0. 254 0.

1.15 6 164 79 1

28

!10719 8

88!S 0 Sue 58.72 l'! 23:3! 12:$f:sf 8 0802 1518 32.R1 34-19.81 8 0803 845 29.76 34-21.06 56 4-22.51 81-20.02 21:18:1A 81-10 81-20 54 49 1.90 1:33 0.30 5.

8: 51*ili1::8:8)8:

-U.40 4 269 2.7 0.0 0.08 9 143 4.8 0.04 0.

0.

6:1 0.0

.5 -

1 1

3.60 01 0 0.5 1 8 0803 10 9 46.e4 34-20.01 81-1e.52 0.86 0 0 57 8 244 1.2 0.06 0.8 1 8 0803 1010 57.89 34-20.01 81-18.23 4.60 -0.24 10 122 098 03

0. 0.5 1 8 0803 1014 50.47 34-19.74 81-18.95 0.67 =0.60 7 247 1. 0.08 Oo04 0.4 0.4 C1 6 0803 1152 1.33 34-20.01 M1-18.51 0.67 0 01 10 123 1. 0.04 0.2 0.3 81 8 0803 13 3 34.80 34-20.16 81-19.49 0.31 -0 40 4 268 2.{s 0.06 0 0.0 C1 8 0803 1840 24.73 34-20.10 88-19.37 1.83 0.37 10 127 2.5 0.04 02

0. 0.4 81 6 0803 2 53 4.98 34-19.23 81-19.86 3.92 -u.24 8 162 3.5 0.04 0.2 0.3 81 8 0804 1 54 24.p2 30-g9,49 81-18.32 0.72 -0.40 8 127 1 0.2 0.4 81 8 0804 2 19 34.91 34 co.01 81-21.05 3.65 -0.24 7 156 5.12 0.06 0.04 0.3 0.7 B1 8 0806 1159 8 81-20.99 2.40 -0.11 9 140 0 0.02 0.3 81 8 0817 836 18.10 56 34-19.79 34-20.01 M1-17.45 0.10 -0 11 7 145 5 5 0.04 07 1 1.1 B1 8 0821 311 24.78 34-19.90 820824 2030 33.54 34-19.61 81-17 R4 1.94 -0 24 6 237 0 2 0.03

0. 05

0. 0.5 C1 81-18 2.62 0.82 9 129 1 0.00 0.4 1 820826 227 51.57 34-20.28 41-19.65 72 2.66 0.37 to 128 360 0.09 0.4 0.8 5 B1 B1

620827 113.19.76 34-19.09 81-16.36 't.32 820827 222 39.19 34-19.6o 1 9 Ido 1 0.04 0.2 0.5 U1 M1-20.14 2 80 45 -0.40 6 257 307 0.01 0.2 0.4 C1 820828 1556 12.68 34-19.47 81-16.50 1.36 -0.11 8 129 0.4 820829 1019 0.0M 34-20.53 81-19.70 3.80 -0.40 9 129 1.4 0.08 0.8 81 8 0907 1154 54.33 34-20.01 81-17.8n 1 -0.40 8 237 3.1 0.2 0.07 0.07 0.3 1.0 0.6 B1 8 0910 2258 49.96 34-20.S2 el-20.82 3.19 88 -0.86 7 135 0.5 C1 8 0918 1819 42.72 34-20.41 81-20.M4 2.60 0.01 8 147 4.9 0.04 0.2 0.4 0.7 81 820918 1820 9.36 14-20.14 81-2n.27 0.44 1.44 8 131 4.8 0.06 1.0 81 820918 19 1 10.27 34-2u.02 81-19.29 4.71 -0.60 6 251 3.9 0.05 0.2 1.0 B1 820918 2071 32.27 3u-20.42 81-20.33 1.94 0.91 10 132 2.4 0.06 1.1 0.7 C1 820918 4.1 0.08 0.3 820919 2338 34.5P 34-29.35 81-20.60 2.67 1.2 81 3s4 48.61 34-19.78 81-20.71

-0.24 6 177 4.5 0.02 0.3 0.6 81 2.35 11 h 138 820922 227o 22.89 34-20.22 81-20.41 1.94 -0 24 9

-0 131 4.6 4.1 0.05 0.08 0.3 0.3 0.9 81 820922 2251 35.76 34-20.01 81-20.17 4.22 -0 60 8 132 3.7 0.05 1 . 2 B l.

8 0922 2337 51.35 34-19.79 8 0923 81-20.12 1.94 -0 69 4 154 R.9 0.04 0.3 0.5 81 0.0.C1 8 0923 4012 42.25 34-20.lo Mi-20.1S 2.98 0.0 1 0.01 10 130 3.8 0.05 0 0.4 B1 B.0a 3u-20.01 81-20.59 3.45 -0 11 9 135 4.4 0.08 8 0925 2220 48.87 34-20.28 81-20.60 1.67 0 21 10 131 4.4 0.09 0

0 0

2 .1 8 B1 81 i

l 1

1