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11-15 February 2008

Ground Motion at Various Sites in Japan

R. Sugahara, M. Nozaki, S. Takeda, H. Yamaoka KEK

S. YamashitaICEPP, The University of Tokyo

Y. NakayamaElectric Power Development Co., Ltd.

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11-15 February 2008

Motivation of this study

• The beam size at the interaction point is very small in a future very high energy electron-positron linear collider. The vertical beam size is about 6nm at the interaction point (IP) in the ILC.

--> Relative stability of the vertical position between final focusing quadrupole magnets installed at both sides of IP is required to be higher than 1nm. In the frequency region higher than 10Hz, the stability of about 10nmis also required in the BDS area and 30nm in the main linac area.

The stability of the ground is one of important issues forthe construction of a future very high energy electron-positron linear collider.

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11-15 February 2008

Contents

1. Comparizon of GM (Ground Motion) at various sitesin Japan

2. Influence of traffic nearby to the GM

3. GM at the time of an earthquake

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11-15 February 2008

Measured Sites

6. Esashi Earth TideObservatory

5. Mitsuse Ro･ad

Tunnel, Sefuri Mt.

1, 2 KEK

4. Shintoyone HydroelectricPower Plant3. SPring-8

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11-15 February 2008

Measured Sites (cont.)Pont 1: Surface near to the D9 electric power station of KEKB at KEK

Geology -- Kanto diluvium formation

Pont 2: KEKB tunnel near to the D9 electric power station at KEK10m deep undergroundGeology -- Kanto diluvium formation

Pont 3: Bottom of the access tunnel of Shintoyone Hydroelectric Power PlantGeology -- granite layer

Pont 4: On the crop of bedrock in the west area of SPring-8Geology -- Kamigori metagabbro layer

Pont 5: Refuge of Mitsuse road tunnel in Sefuri Mountain, SagaGeology -- granite layer

Pont 6: Esashi Earth Tide Observatory of Mizusawa Astronomical ObsevatoryGeology -- granite layer

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11-15 February 2008

KEK site is soft ground area (alternative layers of sand, clay and gravel).The other areas are hard rock areas.

Ground motion was measured with velocity sensors:

VSE355G2 of Tokyo Sokushinn Co., Ltd.at the points 1 - 3

STS-2 of G. Streckeisen AGat the points 4 - 6.

VSE355G2 STS-2 Frequency range (Hz): 0.012 - 70 0.00833 - 50Sensitivity (V/kine): 2.5 15

(* kine = cm/sec)

Measured Sites and Instruments (cont.)

7

11-15 February 2008(a) X-component

(horizontal)in the daytime

(b) Y-component(horizontal)in the daytime

(c) Z-component(verticalal)in the daytime

(d) X-component(horizontal)in the nighttime

(e) Y-component(horizontal)in the nighttime

(d) Z-component(vertical)in the nighttime

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11-15 February 2008(a) X-component(horizontal)in the daytime

(b) Y-component(horizontal)in the daytime

(c) Z-component(vertical)in the daytime

(d) X-component(horizontal)in the nighttime

(e) X-component(horizontal)in the nighttime

(f) X-component(horizontal)in the nighttime

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11-15 February 2008

(a) Z-component(vertical)in the daytime

(b) Z-component(vertical)in the daytime

Power Spectrum Density Integrated Spectrum(Square root of integrated PSD)

1. KEK2. KEK

4. SPring-8

3. Shin-Toyone5. Mitsuse

6. Esashi

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11-15 February 2008

• Amplitude of spectrum density and the integrated spectrum for KEK are larger by 2-4 orders of magnitude and 1-2 orders of magnitude respectively than those for the hard rock area. This is because the KEK site is located in the soft ground area and close to a main road.

• Peak is observed clearly in the KEK site around 3Hz which is said to be caused by artificial vibrational noises such as traffic, motors, etc. This peak around 3Hz is not observed or quite small in the hard rock sites.

• It is interesting that the amplitude of the spectra for Mitsuse road tunnel is as small as those for SPring-8 in spite of frequent traffic near by in the frequency region higher than 1Hz.

Characteristics of Spectra

P2J

P1J

6m

7m

4m

P2A

P1A2. 5m

2m

Edge of the road

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11-15 February 2008

• Amplitude of spectra for Esashi site is the smallest in the frequency region higher than 1Hz. This is because the Esashi site is located in the hard bedrock area and the environment is very quite.

• Amplitude of spectra for sites of hard rock area (points 3 - 6) is almost the same in the frequency region lower than 1Hz. This is because the vibrational source around 0.3Hz is the natural phenomena such asocean swells, winds, etc.

Characteristics of Spectra (cont.)

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11-15 February 2008

0

50

100

150

200

250

300

350

400

450

500

普通車

大型車・ 特大車

124 124 143 151 91 288 220 152 100 66 44 33 4 5 4 12 34 209 429 294 215 193 206

【特記事項】

　・ 18 時台は欠測

　・ 5時台はV TR 不調により7分30 秒分をカウント

　 その後、1 0分あたりに換算（1 0分/7 分3 0秒をかける）

Traffic(a) Mitsuse road tunnel

(b) Higashi O-dori near KEK

0 8 16

0 816

400

200

400

200

Num

ber o

f car

s/H

our

Time slot (Hour)

40

20

0

0

0

Num

ber o

f lig

ht o

r pas

seng

er c

ars/

H

Num

ber o

f tru

cks/

Hou

r

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11-15 February 2008

Main street

At D3 Electric Power Station in KEK

0 .0 0 00

0 .0 0 05

0 .0 0 10

0 .0 0 15

0 .0 0 20

0 .0 0 25

0 .0 0 30

0 .0 0 35

0 .0 0 40

0 .0 0 45

0 .0 0 50

13:0

0～

13:

10

14:0

0～

14:

10

15:0

0～

15:

10

16:0

0～

16:

10

17:0

0～

17:

10

18:0

0～

18:

10

19:0

0～

19:

10

20:0

0～

20:

10

21:0

0～

21:

10

22:0

0～

22:

10

23:0

0～

23:

10

00:0

0～

00:

10

01:0

0～

01:

10

02:0

0～

02:

10

03:0

0～

03:

10

04:0

0～

04:

10

05:0

0～

05:

10

06:0

0～

06:

10

07:0

0～

07:

10

08:0

0～

08:

10

09:0

0～

09:

10

10:0

0～

10:

10

11:0

0～

11:

10

12:0

0～

12:

10

速度

標準

偏差

（(

/)）

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

1 0 0

大型 ・特大車輌通 過台数

D3-P1

D3-P2

D3-P3

D3-P4

0 .0 0 0 0

0 .0 0 0 5

0 .0 0 1 0

0 .0 0 1 5

0 .0 0 2 0

0 .0 0 2 5

0 .0 0 3 0

0 .0 0 3 5

0 .0 0 4 0

0 .0 0 4 5

0 .0 0 5 0

速度

標準

偏差

（(

/)）

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

1 0 0

大型 ・特 大車輌通 過台 数

D3-P 1

D3-P 2

D3-P 3

D3-P 4

RM

S of

Sig

nals

(kin

e/ho

ur)

016 8Time Slot (H)

Num

ber o

f Tru

cks

Pass

ing

By

/ H

Number of Trucks/H

(a) Horizontal component(N-S)

(b) Vertical component

• GM has a good correlation with the passage of heavy cars

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11-15 February 2008

JP1

JP2JP3 JP4

GROUND MOTION AT THE TIME OF AN EARTHQUAK

SPring-8 site

JP1: on an outcrop of the bedrock

JP2: on a granite base block in a room

JP3: a mound covering the XFEL beam line

JP4: ground at the east gate

Earthquake was observedat 00:05:30 on 11 July 2004at the time of remeasurementat Spring-8

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11-15 February 2008

Beats caused by mortors working nearby

P-waveS-wave

Output From Sensors

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11-15 February 2008

Power Spectrum Density at The Time of an Earthquake

(a) Horizontal component(N-S)

(b) Vertical component

0.1 1 1０

JP1

JP2JP3

JP4

Frequency (Hz)

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11-15 February 2008

JP1

JP2JP3

JP4

Integrated Spectra at The Time of an Earthquake

0.1 1 1０

10-2

10-４

10-６

10-2

10-４

10-６

Am

plitu

de (m

m)

Frequency (Hz)

(a) Horizontal component (N-S)

(b) Vertical component

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11-15 February 2008

< --- >

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11-15 February 2008

GM in the Midnight at SPring-8

(a) Horizontal component (N-S)

(b) Vertical component

0.1 1 1０

Frequency (Hz)

PSD

(mm

2 /Hz)

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11-15 February 2008

GM in the Midnight at SPring-8 (cont.)

(b) Vertical component

(a) Horizontal component (N-S)

0.1 1 1０

Frequency (Hz)

Am

plitu

de (m

m)

10-2

10-４

10-６

10-2

10-４

10-６