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Underground Water Observation in Wari-ishi Hot Spring, Gifu Prefecture
Shigeki Tasaka[1]; Yoshimi Sasaki[2]; Masaya Matsubara[3];
Norio Matsumoto[4]; Akito Araya[5][1] IMC, Gifu Univ; [2] Faculty of Educ., Gifu Univ.; [3] IMC, Gifu Univ.; [4] GSJ, AIST; [5] ERI, Univ. Tokyo
7th Japan-Taiwan International Workshop on Hydrological and Geochemical Research for Earthquake Prediction
Date:Oct.7, 2008Place: Site C-7, Geological Survey of Japan, AIST,
Tsukuba, Japan
IntroductionThe observation result of underground-water discharge are related to the crustal stress accompanying the earth tide or the occurrence of earthquakes through change of the pore pressure of aquifer layer.
The purpose of this presentation is to clarify the relations of water changes and crust distortion. Analysis of discharge water were performed in the following five viewpoints;
1.Observation site and method2.Detection of co-seismic changes3.Earth Tide Analysis4.Hydro-Seismic Oscillation in 1Hz Sampling Data5.FFT Analysis of Discharge Water and Local Strain
Observation Method(1)Water Discharge were observed in Wari-
ishi Hot Spring by Gifu Univ. and Gifu Pref.• 1st period:1977-1998 Observed by Bucket
and Stopwatch on every Monday• 2nd period:1998-2003 Electromagnetic
Flow Meter in 10 min interval• 3rd period:2004-2008 Electromagnetic
Flow Meter in 1 Hz sampling(2)Broadband Observation with Laser Strain
Meters in KAMIOKA-Mine by Earthquake Research Institute, Univ. of Tokyo
Observation Site Wari-ishi Hot Spring and Kamioka Mine
36.3N,137.2E
5km from site
8) Off Tokachi
(2003:M8.0)
5) Gifu Hida
(1998:M5.2)
10) Chuetsu (2004:M6.8)
2) Western Nagano(1984:M6.8)
6) Western Ishikawa (2000:M5.8)
4) Off Noto
Peninsula(1993:M6.6)
1)Central Japan Sea (1983:M7.7)
7) Western Tottori (2000:M7.3)
Wari-ishi Hot Spring9)Off Kii
Peninsula(2004:M6.9/M7.4)
3) Northern Nagano (1986:M5.9)
13) Off Chuetsu (2007:M6.8)
11)Gifu Hida
(2005:M3.0)
12)Noto Peninsula (2007:M6.9)
•1st period :EQ 1)- 4)•2nd period:EQ 5)- 8)•3rd period :EQ 9)-15)
14) Off Kushiro (2004:M7.1)
15) Off Ibaraki (2008:M6.7)
Epicenter Distribution with Co-seismic Changes of Water Discharge (1977-2008)
Dilatation
Dilatation
Compression
Seismic Changes of Water Discharge in Wari-ishi (1977-2008)Earthquake date Distance (km) Magnitude FMAX :Max Water Flow (L/min)
1)Central Japan Sea 1983/05/26 472 7.7 -45.0
2)Western Nagano 1984/09/14 66 6.8 21.4
3)Northern Nagano 1986/12/30 64 5.9 4.0
4)Off Noto Peninsula 1993/02/07 145 6.6 20.0
5)Gifu Hida 1998/08/12 35 4.7 12.0
6)Western Ishikawa 2000/06/07 165 6.2 2.0
7)Western Tottori 2000/10/06 375 7.3 3.2
8)Off Tokachi 2003/09/26 856 8.0 3.3
9)Off Kii Peninsula(1) 2004/09/05 377 7.1 0.5
9)Off Kii Peninsula(2) 2004/09/05 363 7.4 4.5
10)Chyuetsu 2004/10/23 176 6.8 6.3
11)Gifu Hida(close to site) 2005/02/25 7 3.0 14.7
12)Noto Peninsula 2007/03/25 109 6.9 34.1
13)Off Chyuetsu 2007/07/16 178 6.8 0.5
14)Off Kushiro 2004/11/29 7.1 Oscillation Waveform
15)Off Ibaraki 2008/05/08 6.7 Oscillation Waveform
A) Sumatra 2004/12/26 5609 9.3 Oscillation Waveform
B) Taiwan 2006/12/26 2285 6.7 Oscillation Waveform
C) Far Chishima 2007/01/13 1804 8.3 Oscillation Waveform
D) China Cichuan 2008/05/12 7.8 Oscillation Waveform
Time variations of Water Discharge (3rd period:2004-2008)
9)Off Kii2004/9/5
M7.4 D=360kmStep:5L/min
10) Chyuetsu2004/10/23
M6.8 D=185kmStep:6.3L/min
11) Gifu Hida2005/2/25
M3.0 D=7kmStep:10L/min
12) Noto2007/3/25
M6.9 D=108kmStep:35L/min
13)Off Chyuetsu2007/7/16
M6.8 D=172kmStep:1L/min
14) Off Kushiro2004/11/29 M7.1
Oscillation
B) Taiwan2006/12/26 M7.1
Oscillation
C) Chishima2007/01/13 M8.3
Oscillation
15) Off Ibaraki2008/5/8 M6.7
Oscillation
Base Water Flow:30(L/min)
A) Sumatra2004/12/26 M9.0
Oscillation
Date(2004-2008)
1
10
100
0 30 60 90 120 150day
Wat
er
Decre
ase (
L/m
in)
2)Nagano1998
12)Noto2007
11)Hida2005
5)Hida1998
10)Chyuetsu2004
Attenuation Curve to steady state after 5 EQ
Earthquake (with Step) FMAX (L/min)Max Water Flow T1/2 (day)
2) Nagano 1984(M6.8) 21.4 1315) Hida 1998(M5.4) 12.0 151
10) Chyuetsu 2004(M6.8) (added to Kii) 11.3 165 11) Hida 2005(M3.2) 14.7 13812) Noto 2007(M6.9) 34.1 162
Half Time to steady stateT1/2 =149±15(day)
F (t)=FMAX EXP(-λt), T1/2 =LN2/λ
Tidal Response AnalysisStart and end Time 2007/01/15-2007/3/25
•Trend component•Irregular component
Flow Rate/Discharge WaterAtmospheric Pressure
BAYTAP-GTidal ResponseAtmospheric Response
•Tidal Amplitude•Solved Gas
0.74 l/min
2007/01/15
12)Off Noto 2007/3/25
Trend Component
Atmospheric Pressure Response
Tidal Response
Irregular Comp.
Discharge Water(observation)
Atmospheric Pressure(observation)
Tidal Amplitude of Discharge Water in Wari-ishiM2: 0.158(L/min) O1: 0.099(L/min)
Tidal Strain Calculated by GOTIC2 M2:0.997, O1:0.671(10-8 cubic strain)Sensitivity of Discharge Water M2:0.16, O1:0.15(L/min)/(10-8 cubic strain)
0.04
0.08
0.12
0.16
0.20
Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Jan-08
amplitude M2 amplitude 01
M2
and
O1
Am
plitu
de (L
/min)
12)Noto2007/3/25 M6.9
5)Gifu Hida1998/8/16 M5.2
8)Off Tokachi2003/9/26 M8.0
9)Off Kii2004/9/5 M7.4
Tidal O1 and M2 Amplitude(1998-2007)
26283032343638
0 50 100 150 200 250 300
2 L/min
Hydro-seismic waveform with step-like increase
29
30
31
32
33
0 50 100 150 200 250 300
2 L/min
34
35
36
37
38
0 50 100 150 200 250 300
2 L/min10) Chyuetsu (2004/10/23 17:56) M 6.8 D=178km
9) Off Kii(1) Peninsula (2004/9/5 19:07) M 6.8 D=374km
9) Off Kii(2) Peninsula (2004/9/5 23:57) M 7.2 D=362km
Time(sec)
Step FMAX =4.5
Step FMAX =0.5
Step FMAX =6.3
P-Wave :Dilatation
P-Wave :Dilatation
P-Wave :Compression
51
52
53
54
0 30 60 90 120 150 180 210 240 270 300
2 L/min
13) Off Chyuetsu (2007/7/16 10:28) M6.8 D=173km
Step FMAX =0.5
P-Wave :Compression
30
35
40
45
0 50 100 150 200 250 300
5 L/min12) Noto Peninsula (2007/3/25 09:41) M6.9 D=108km
Step FMAX =34.1P-Wave +:Dilatation
36
38
40
42
44
0 30 60 90 120 150 180 210 240 270 300
2 L/min
11) Gifu Hida (2005/2/25 06:27) M3.0 D=7km(close to site)
Step FMAX =14.7
38
39
40
0 30 60 90 120 150 180 210 240 270 300
2 L/min 14) Off Kushiro (2004/11/29 03:32) M 7.1
Oscillation
-2
-1
0
1
2
0 30 60 90 120 150 180 210 240 270 300
2 L/min
Time(sec)
Hydro-seismic Waveforms step-like increase and Oscillation
Oscillation
15) Off Ibaraki (2008/5/8 1:45) M6.7
Hydro-seismic Waveforms of Far Big Earthquakes
33
37
41
45
0 240 480 720 960 1200 1440 1680 1920 2160 2400
9.1 L/min
29
30
31
0 240 480 720 960 1200 1440 1680 1920 2160 2400
0.9 L/min
28
30
32
0 240 480 720 960 1200 1440 1680 1920 2160 2400
3.7 L/min
29
31
33
0 240 480 720 960 1200 1440 1680 1920 2160 2400
3.7 L/minD) Cichuan(China) (2008/5/12) M7.8
C) Chishima (2006/1/13) M8.3
B) Taiwan(2006/12/26) M7.1
A) Sumatra(2004/12/26) M9.0
Time(sec)
Oscillation
Oscillation
Oscillation
Oscillation
FFT Analysis of Discharge Water and Area strain
Frequency Region: 10-50mHzAmplitude Ratio (Water/Strain)0.13±0.05(L/min)/(10-8strain)
(a) Waveforms
(b) FFT Amplitude
(c) Amplitude Ratio Water/Strain
0 .13±0 .05
Water
Strain
Water
Strain
KII Earthquake(2)(2004/9/5 M7.4)with step-like increase
FMax =3.5(L/min)
FFT Analysis of Discharge Water and Area strain
Frequency Region: 3-50mHzAmplitude Ratio (Water/Strain)0.17±0.07(L/min)/(10-8strain)
(a) Waveforms
0.17±0 .07
(b) FFT Amplitude
(c) Amplitude Ratio Water/Strain
Water
Strain
Water
Strain
Sumatra Earthquake(
2004/12/26 M9.3 )
without step increase
Summary(1) Seismic Change of Water Discharge in Wari-ishi 19
Earthquakes (1977-2008) (2) Attenuation Curve to steady state after 5 Earthquake
F(t)=FMAX EXP(-λt), T1/2 =149±15(day)(3) Tidal Analysis of O1 and M2 Amplitude(1998-2007)
O1(25.8h):0.16M2(12.4h):0.15 (L/min)/(10-8 strain)
(4) Initial water change (Dilatation/Compression) consistent with the Focal Mechanism Solution of Earthquake.
(5) FFT Analysis of Discharge Water and Area Strain Region of Frequency 3mHz-50mHz
Kii Peninsula EQ (1) (2) :
0.13±0.05Sumatra EQ:0.17±0.07 (L/min)/(10-8 strain)