SLOW GROUND MOTION STUDIES IN KEK · Slow Ground Motion Studies in KEK Frequency Dependence of Ground Motion ... KEK Earthquake and Artificial Noises Ocean Swell Ground motion in

Yamamoto and Takeda

Slow Ground Motion Studies in KEK

SLOW GROUND MOTION STUDIES IN KEK Geology DependenceGeology DependenceGeology DependenceGeology Dependence

Noboru Yamamoto and Shigeru Takeda

KEK, High Energy Accelerator Research Organization

Power Spectrum Density and Coherence Slow Ground Motion and Geology Slow Ground Motion and Excavation MethodsSlow Ground Motion and Excavation MethodsSlow Ground Motion and Excavation MethodsSlow Ground Motion and Excavation Methods

Slow Ground Motion Studies in KEK Typical Parameters of JLC

Typical Parameters of Linear Collider

XXXX----bandbandbandband CCCC----bandbandbandband Beam Energy Entrance/Exit Beam Energy Entrance/Exit Beam Energy Entrance/Exit Beam Energy Entrance/Exit E0/E1E0/E1E0/E1E0/E1 10/50010/50010/50010/500 10/50010/50010/50010/500 GeVGeVGeVGeV Particles/bunch Particles/bunch Particles/bunch Particles/bunch N N N N 0.8 0.8 0.8 0.8 1.0 1.0 1.0 1.0 10 10 10 1010101010

Invariant Emittance Invariant Emittance Invariant Emittance Invariant Emittance ε N y 30 30 30 30 30 30 30 30 nm nm nm nm Bunch length Bunch length Bunch length Bunch length σ z 80 80 80 80 200 200 200 200 µµµµmmmm β at entrance at entrance at entrance at entrance β 0 4 4 4 4 4 4 4 4 m m m m Rf Rf Rf Rf frequencyfrequencyfrequencyfrequency ffff 11.4 11.4 11.4 11.4 5.7 5.7 5.7 5.7 G G G GHHHHzzzz Accel. gradient Accel. gradient Accel. gradient Accel. gradient dE/dsdE/dsdE/dsdE/ds 45 45 45 45 32 32 32 32 MeV/mMeV/mMeV/mMeV/m Iris radius/wavelength Iris radius/wavelength Iris radius/wavelength Iris radius/wavelength a / λ 0.16 0.16 0.16 0.16 0.14 0.14 0.14 0.14

ATL coefficient ATL coefficient ATL coefficient ATL coefficient A A A A 1 1 1 1 1 1 1 1 nm nm nm nm2222/s/m/s/m/s/m/s/m Stable time for Stable time for Stable time for Stable time for ∈ =0.1 =0.1 =0.1 =0.1 tttt 3 3 3 3 24 24 24 24 hours hours hours hours

Yamamoto and Takeda

Slow Ground Motion Studies in KEK Sensors for Ground Motion Studies

Yamamoto and Takeda

ATL COEFFICIENT in JAPAN

No Site Name A (nm2/m/sec) Geology of the Place1 Tunnel of KEKB 4.0E+01 Clay and Gravel2 Rokkoh-1 3.6E+01 Granite (near Fault)3 Rokkoh-2 3.3E+01 Granite4 Miyazaki 1.5E+01 Diorite5 Kamaishi-1 1.4E-01 Granite (Crack and Water)6 Kamaishi-2 5.7E-02 Granite7 Sazare 5.0E-02 Green Schist8 Esashi-1 5.7E-03 Granite (Floating Stone)9 Esashi-2 2.0E-03 Granite

Geological Map of Japan and the Present Data Taking Site.

Described numbers are the same in figures and Table.

No. 1

No. 2, 3

No. 4

No. 5, 6

No. 7

No. 8, 9

GRANITE GOOD for LC

Sedimentary Layer

Volcanic Rock

Slow Ground Motion Studies in KEK Geological Map and Sites for Data Taking

Yamamoto and Takeda

Yamamoto and Takeda

Slow Ground Motion Studies in KEK Frequency Dependence of Ground Motion

1E-71E-61E-5 1E-41E-31E-2 1E-1 1 1E1 1E21E-161E-151E-141E-131E-121E-111E-10

1E-91E-81E-71E-61E-51E-41E-31E-21E-11E01E11E21E31E41E51E61E71E81E9

1/f4

1/f 2

OCEAN SWELL

SAZARE

EARTH-TIDESPo

wer

Spe

ctru

m D

ensi

ty ( µ µµµ

m2 /H

z)

frequency (Hz)

frequency range f<0.1 Hz: The measured power spectrum of ground motion can be characterized by 2/ fk . This coefficient k has site dependence and changes from 1 to 102 nm2/Hz. The earth-tide, one of the elastic motions in this low frequency range, becomes cause of inelastic motion through its dissipation. One of the models describing this inelastic ground motion is the ATL model.

frequency range f>0.1 Hz: The power spectrum density decreases very rapidly with frequency being proportional to 4/1 f .

Slow Ground Motion Studies in KEK What Happen in the Noisy Site (f>0.01Hz)

1E-2 1E-1 1 10 1E21E-12

1E-11

1E-10

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

1E-2

1E-1

1

10

1E2

Quiet Site: Sazare

Traf

fic N

oise

s

Pow

er S

pect

ral D

ensi

ty ( µ µµµ

m2 /H

z)

frequency (Hz)

Noisy Site: KEK

Earth

quak

e an

d Ar

tific

ial N

oise

s

Ocean Swell

Ground motion in the noisy site (KEK). Coherence between two points at a distance of 48 m. Power spectra for the two points are the same. Incoherent spectrum is given by the equation shown in the figure. A big bump spectrum, around 0.2 Hz, corresponds to the ocean swell. The incoherent spectrum around 3 Hz comes from traffic noises. This incoherent vibration gives an amplitude of 83 nm. That is, the tunnel in KEK should have a depth of 900 m, providing we want the amplitude of 1 nm.

1E-2 1E-1 1 101E-5

1E-4

1E-3

1E-2

1E-1

1

10

Pow

er S

pect

rum

Den

sity

(µ µµµm

2 /Hz)

frequency (Hz)

1E-3

1E-2

1E-1

1

(1-Coherence) x (RAW SPECTRUM)

RAW SPECTRUM

Coh

eren

ce

Yamamoto and Takeda

Slow Ground Motion Studies in KEK What Happen in the Noisy Site (f>0.1 Hz)

1 10 1E21E-12

1E-11

1E-10

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

1E-2

1E-1

QUIET SITE No. 4

NOISY SITE No. 3

Spec

trum

(µ µµµm

2 /Hz)

frequency (Hz)

1E-2 1E-1 1 10

1E-1

1No 3

No 2

CO

HER

ENC

E

frequency (Hz)

Coherence in the Granite tunnel. Two sensors at a

distance of 60 meters are used to get coherence. No. 3

shows that both sensors stand on the good granite rocks.

No. 2 shows that there is a fault, about 10 m wide, among

the sensors. The amplitude of No. 2 is rapidly decrease in

the frequency range higher than 0.4 Hz. No. 2 also shows

the amplitude is about 0.85 in the frequency range lower

than 0.3 Hz. But A is not so different each other as shown

in the table of ATL COEFFICIENT.

Yamamoto and Takeda

Slow Ground Motion Studies in KEK What Happen in the Tidal Frequency Region

2627282930313233343536

0 2880 5760 8640 11520 14400 17280 20160 23040-33-32-31-30-29-28-27-26-25-24-23

-3-2-101234567

#2

time (min)

Ground Motion at Esashi (by LSHF)

#1

#3Ve

rtica

l Pos

ition

(µ µµµm

)

The time series data on the vertical ground motions observed at three points being 14 m apart between one another.

Yamamoto and Takeda

Yamamoto and Takeda


1E-6 1E-5 1E-4 1E-3 1E-21E-4

1E-3

1E-2

1E-1

1

10

1E2

1E3

1E4

1E5Ground Motion at Esashi (by LSHF)

#2

#1

Pow

er S

pect

rum

Den

sity

( µ µµµm

2 /Hz)

frequency (Hz)

1E-6 1E-5 1E-4 1E-3 1E-2

1E-1

1

1E-1

1

#1-#2

CO

HER

ENCE

frequency (Hz)

#2-#3

Coherence in the Granite Tunnel Having a Floating Lumped Rock.

Except the #1 lumped rock position, we get good coherence.

#1 shows no earth-tide spectrum. ATL coefficient in this point is a little bad as shown in the previous ATL Table.


Yamamoto and Takeda

N

3 km from the Entrance

<Dam>:Controls the Ground Water Level

Excavated by Slow Blasting Method

#1～#4:Geodetic Platform Tiltmeter (Resolution: 0.05μrad)Auxiliary Sensor: 3D Velocity Vibration Meter

Granite Flat Base, on which the sensor is setting up.

#1 17 m#2 17 m

#3 17 m#4

1E-6 1E-5 1E-4 1E-3 1E-2

1E-1

1

1E-1

1

1E-1

1

COH

EREN

CE

9910frequency (Hz)

X1-X2

X1-X3

X2-X3

EFFECT of BLASTING CREVICE:

We executed several experiments to get detailed information

about the surface layer of the granite tunnel cut by SBM.

The coherence shows very complex changes without the dam.


Yamamoto and Takeda

1E-5 1E-4 1E-3 1E-21E-4

1E-3

1E-2

1E-1

1

10

1E2

1E3

1E4

1E5

EARTH-TIDES

2 mHz

X1

X2

X4

Tilt

( µ µµµra

d2 /Hz)

Frequency (Hz)

1E-1

1

1E-1

1

1E-6 1E-5 1E-4 1E-3 1E-2

1E-1

1

X1-X2

X3-X2

X4-X2

CO

HER

ENC

E

Frequency (Hz)

In order to check the activity of underground water, we built

a dam across the flow to control the water level in the crevice.

• #2 was mostly suffered by the reaction between the crevice and

the water.

• #4 is another effect, such as lumped rock like Esashi.

SLOW GROUND MOTION STUDIES IN KEK · Slow Ground Motion Studies in KEK Frequency Dependence of Ground Motion ... KEK Earthquake and Artificial Noises Ocean Swell Ground motion in

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