japan earth-quake november 15, 2006
DESCRIPTION
Serendipitously recorded at MGL Using 5 Newly Built Pet Meters (The meters were not ready for shipment). Japan Earth-Quake November 15, 2006. Earth-quake recorded with seismometers in Salt-Lake City, UT. Earth-quake recorded with PET 28 gravity meter in Lafayette, CO. Pre-Earthquake Data - PowerPoint PPT PresentationTRANSCRIPT
Japan Earth-QuakeNovember 15, 2006
Serendipitously recorded at MGL
Using 5 Newly Built Pet Meters
(The meters were not ready for shipment)
0 1 2 3 4 5 6
x 104
0
2000
4000
6000
8000
10000
12000
14000
16000
18000PET 28
Seconds
mic
roG
al
Earth-quake recorded with seismometers in Salt-Lake City, UT
Earth-quake recorded with PET 28 gravity meter in Lafayette, CO
0 0.5 1 1.5 2 2.5 3 3.5 4
x 104
-9000
-8900
-8800
-8700
-8600
-8500
-8400
PET 35Tidal Portion
0 0.5 1 1.5 2 2.5 3 3.5 4
x 104
6700
6800
6900
7000
7100
7200
7300
7400
PET 37Tidal Portion
0 0.5 1 1.5 2 2.5 3 3.5 4
x 104
6250
6300
6350
6400
6450
6500
6550
6600
6650
PET 39Tidal Portion
0 0.5 1 1.5 2 2.5 3 3.5 4
x 104
3700
3750
3800
3850
3900
3950
4000
4050
PET 34Tidal Portion
0 0.5 1 1.5 2 2.5 3 3.5 4
x 104
8650
8700
8750
8800
8850
8900
8950
9000
PET 28Tidal Portion
Pre-Earthquake Data
(Meters are not yet ready to ship)
*Time series data (1s) prior to earth quake. Note that PET 35 has high drift
0 2000 4000 6000 8000 10000 12000 14000 160000
2000
4000
6000
8000
10000
12000
14000
16000
18000PET 28
sec
uGal
0 2000 4000 6000 8000 10000 12000 14000 16000-18000
-16000
-14000
-12000
-10000
-8000
-6000
-4000
-2000
0PET 35
sec
uGal
0 2000 4000 6000 8000 10000 12000 14000 16000-2000
0
2000
4000
6000
8000
10000
12000
14000
16000PET 37
sec
uGal
0 2000 4000 6000 8000 10000 12000 14000 16000-2000
0
2000
4000
6000
8000
10000
12000
14000
16000PET 39
sec
uGal
* All Plotted on Same Scale (18 mGal scale)
After onset of Earthquake (4 hour record, 1s data)
0 2000 4000 6000 8000 10000 12000 14000 16000-5000
-3000
-1000
1000
3000
5000
7000
9000
11000
13000PET 34
Sec
uGal
1100 1150 1200 1250 1300 1350 1400 1450
0.6
0.8
1
1.2
1.4
1.6x 10
4
Seconds
mic
roG
al
Onset of Earthquake (PET 28)
Onset of earthquake from PET 28
(6 minutes)
2600 2700 2800 2900 3000 3100 3200 3300 3400 35000
2000
4000
6000
8000
10000
12000
14000
16000
PET 28Japan Earthquake
2600 2700 2800 2900 3000 3100 3200 3300 3400 3500
-4000
-2000
0
2000
4000
6000
8000
10000
12000
14000
PET 34Japan Earthquake
2600 2700 2800 2900 3000 3100 3200 3300 3400 3500
-16000
-14000
-12000
-10000
-8000
-6000
-4000
-2000
0
PET 35Japan Earthquake
2600 2700 2800 2900 3000 3100 3200 3300 3400 3500-2000
0
2000
4000
6000
8000
10000
12000
14000
16000
PET 37Japan Earthquake
2700 2800 2900 3000 3100 3200 3300 3400 3500 3600-2000
0
2000
4000
6000
8000
10000
12000
14000
16000
PET 39Japan Earthquake
All Pet Meters
(Time series data - 15 minutes during earthquake)
1300 1400 1500 1600 1700 1800-2
-1.5
-1
-0.5
0
0.5
1
1.5
2x 10
4
sec
uGal
Pet Meters During Earth-Quake (10 minutes)
Five PET meters during earth-quake
Plotted with original feedback offsets of meters (±10 mGal)
-300 -200 -100 0 100 200 300-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1PET 28-X-PET 34
-300 -200 -100 0 100 200 300-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1PET 28-X-PET 35
-300 -200 -100 0 100 200 300-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1PET 28-X-PET 37
-300 -200 -100 0 100 200 300-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1PET 28-X-PET 39
-300 -200 -100 0 100 200 300-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1PET 34-X-PET 35
-300 -200 -100 0 100 200 300-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1PET 34-X-PET 37
Cross covariance (± 5minutes Lag)
*Correlation is limited to about 90-98% because of clock differences (±0.5s)
-300 -200 -100 0 100 200 300-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1PET 37-X-PET 39
-300 -200 -100 0 100 200 300-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1PET 34-X-PET 39
-300 -200 -100 0 100 200 300-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1PET 35-X-PET 37
-300 -200 -100 0 100 200 300-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1PET 35-X-PET 39
Cross correlation (± 5minutes Lag)
Continued….
*Correlation is limited to about 90-98% because of clock differences (±0.5s)
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.50
1
2
3
4
5
6
7
8
9x 10
5
Frequency
PET 28 - (6 minutes of data after first shock)
Linear-Linear Plot
Spectrum of 1 hour of data
(after start of earthquake)
10-4
10-3
10-2
10-1
100
0
1
2
3
4
5
6
7
8
9x 10
5
Frequency
PET 28 - (6 minutes of data after first shock)
Linear-Log Plot
Continued….
Spectrum of 1 hour of data (after start of earthquake)
10-4
10-3
10-2
10-1
100
102
103
104
105
106
Frequency
PET 28 - (6 minutes of data after first shock)
Log-Log Plot
Continued….
Spectrum of 1 hour of data
(after start of earthquake)
Low frequencies in earth-quake (1 hr record)
22.4 s 19.6 s 17.7 s26.1 s29.1 s32.3 s40.0 s51.3 s69 s
1000 2000 3000 4000 5000 6000 7000 8000 9000
-6000
-4000
-2000
0
2000
4000
6000
8000
Seconds
mic
roG
al
All 5 Pet Meters Stacked (Averaged)
Onset of Earth QuakeStacking of all 5 PET meters
Onset of Earth QuakeStacking of all 5 PET meters(a closer look at beginning)
1200 1400 1600 1800 2000 2200 2400 2600 2800 3000
-6000
-4000
-2000
0
2000
4000
6000
8000
Seconds
mic
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al
All 5 Pet Meters Stacked (Averaged)
Continued…
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.50
20
40
60
80
100
120
Frequency
mic
roG
al
FFT of 5 Stacked PET Meters (4.3 hours during quake)
FFT (full)
0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.080
20
40
60
80
100
120
Frequency
mic
roG
al
FFT of 5 Stacked PET Meters (4.3 hours during quake)
FFT (low frequencies)
Continued…
Frequencies in Earthquake
y = 0.0051x + 0.0092
0
0.01
0.02
0.03
0.04
0.05
0.06
1 2 3 4 5 6 7 8 9
Harmonic #
Fre
qu
en
cy
0
10
20
30
40
50
60
70
80
Se
co
nd
s
FrequenciesPeriodsLinear (Frequencies)
Linear Fit
Plot of Frequencies in FFT
*The frequencies appear to be harmonics
y = 124590x-1.9205
0
100
200
300
400
500
600
0 10 20 30 40 50 60 70 80
Sec
mG
al
Amplitude of earth-quake peaks (plotted versus period)
(4 hours of data after start of shock)
Amplitude appears to follow power law
y = 124590x1.9205
10
100
1000
0.01 0.1
Sec
mG
al
Amplitude of peaks (4 hours of data after start of shock) plotted against frequency
Conclusions All five PET meters saw essentially the
same earth-quake signal of 18mGal p-p The main differences in the signal were
due to fact that time synchronization was not set (± 0.5s discrepancies between meters).
The peaks appeared to be harmonics that roughly followed a power law in amplitude