Документ взят из кэша поисковой машины. Адрес оригинального документа : http://zebu.uoregon.edu/~uochep/talks/talks03/G030641-00.pdf Дата изменения: Tue Oct 12 21:46:16 2004 Дата индексирования: Tue Oct 2 11:25:03 2012 Кодировка: Поисковые слова: storm

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S2 Intersite Environmental Transients
Investigation

lightningphotography.com

Robert Schofield (Oregon)

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QUESTIONS
1) Do large local voltage spikes and lightning strikes show up on AS_Q? If not, smaller events that show up at both sites probably wont either. 2) Is there any evidence of coincident PEM events at greater than chance? 3) Correlations on a time scale longer than light travel time? 4) GPS associated events?

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Nearby Lightning Not Seen on GW Channel
Storm during S2 over Rattlesnake Mountain ~ 10 km Strike seen on fluxgate magnetometers at both stations:
600 400

Signal

200 0 -200 -400 19.1
H0:PEM-BSC10_MAGX H0:PEM-BSC10_MAGY H0:PEM-BSC10_MAGZ H0:PEM-BSC1_MAG1X H0:PEM-BSC1_MAG1Y H0:PEM-BSC1_MAG1Z

19.12

19.14

19.16

19.18

19.2 Time (s)

19.22

19.24

19.26

19.28

19.3

T0=14/04/2003 04:56:27

Avg=1

Not seen on H1 AS_Q
0.06
H1:LSC-AS_Q

0.04 0.02

Signal

0 -0.02 -0.04 -0.06 19.1 19.12 19.14 19.16 19.18 19.2 Time (s) 19.22 19.24 19.26 19.28 19.3

T0=14/04/2003 04:56:27

Avg=1

High-pass and comb-filtered time series

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Strike at LHO Not Obvious at LLO Coil Magnetometers
LHO fluxgate magnetometers:
400 300 200

Signal

100 0 -100 -200 99.6

H0:PEM-BSC10_MAGX H0:PEM-BSC10_MAGY H0:PEM-BSC10_MAGZ H0:PEM-BSC1_MAG1X H0:PEM-BSC1_MAG1Y H0:PEM-BSC1_MAG1Z

99.65

99.7

99.75

99.8 Time (s)

99.85

99.9

99.95

100

T0=14/04/2003 04:59:47

Avg=1

LLO coil magnetometers:
8000
H1:LSC-AS_Q

6000 4000 2000 0

L0:PEM-COIL_MAGZ L0:PEM-COIL_MAGY L0:PEM-COIL_MAGX

Signal

-2000 -4000 -6000 99.6 99.65 99.7 99.75 99.8 Time (s) T0=14/04/2003 04:59:47 Avg=1 99.85 99.9 99.95 100

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Line voltage glitch that appears at multiple LHO stations does not show up on AS_Q

400 300 200 100 H0:PEM-EY_V1 H0:PEM-EX_V1 H0:PEM-LVEA2_V2 H0:PEM-LVEA2_V1

Signal

0 -100 -200 -300 99 99.2 99.4 99.6 99.8 100 100.2 100.4 100.6 100.8 101

Time (s)
T0=20/02/2003 13:36:42 Avg=1

0.04 0.03 0.02 0.01

H1:LSC-AS_Q

Signal

0 -0.01 -0.02 -0.03 -0.04 99 99.2 99.4 99.6 99.8 100 100.2 100.4 100.6 100.8 101

Time (s)
T0=20/02/2003 13:36:42 Avg=1

High-pass and comb-filtered time series

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magMon algorithm for detecting PEM bursts that are coincident between sites
· Modification of an older version of glitchMon · Coincidence before trigger generation to explore low thresholds · Can insist on coincidence between multiple channels (e.g. on 2 of 3 voltage monitors at each site) · Coincident event rates for aligned and offset LHO and LLO time series

No excess over chance coincidence found in coil magnetometers:
L0:PEM-COIL_MAGX; H0:PEM-COIL_MAGY; 560-580 Hz 4th order butterworth; 2,370,460 seconcs of S2

Threshold (sigma) 5.1 4.65 4.2 3.75 3.3 2 29

Events exceeding threshold 3

Events for offset time series

(on - off) -1 -6 -10 63 28

sqrt(on+off) 2.24 8 22.7 61 172

35 263 1826 14711

253 1889 14739


No excess found in LLO and LHO line voltage monitors:
L0:PEM-EX_V1;;L0:PEM-EX_V2;L0:PEM-LVEA_V1;H0:PEM-H0:PEM-LVEA2_V2;

Threshold (sigma) 3.5 3.1 2.7 2.3 1.9 3

Events exceeding threshold

Events for offset time series 10 121 3924 109989 960138

(on - off) -7 31 -82 345 1224

sqrt(on+off) 3.60 16.5 88.1 469 1386

152 3842 110334 961362

MY_V1; H0:PEM-LVEA2_V1; 1,144,260s of S2 data; only 1 event allowed each second; only 2 signals in excess of threshold demanded from each site.

No excess found in radio channels:
H0:PEM-RADIO_LVEA; H0:PEM-RADIO_LVEA; 1,994,456 s

Threshold (sigma) 7.35 6.7 6.05 5.4 4.75 2 2 10 50

Events exceeding threshold 0 6

Events for offset time series

(on - off) 2 -4 0 14 14

sqrt(on+off) 1.41 2.8 4.5 9.3 15.7

10 36 116

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Correlated Increase In LHO and LLO Event Rates During Working Hours
Average number of triggers (for hours with triggers) First 27 days of S2; TFC triggers with SNR > 120, central f > 100, duration < 1 50 H1 L1 40

30

20

10

0

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Hour of the day, Pacific Standard Time

Probably associated with up-conversion of anthropogenically increased seismic signal. Time shifts for background calculations should be small; look for correlations on scale of time shifts.

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No Evidence of Increased Trigger Rate During Particular Part of GPS Second
small sample, though
6000 5500 TFClusters slope

number of burst triggers

5000 4500 4000 3500 3000 2500 2000 1500 1000 500 0 0 0.2 0.4 0.6 0.8 1

trigger start time within GPS second

Triggers for LHO; H1 or H2 SNR: TFC :7; slope: 8 Total number of events: TFC: 40000; slope: 60000 Total number of seconds with events: TFC: 21120; slope:50165

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