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I,on.!: rC/ngc s/roc/.. II'(/\'CS /rol/1 (/ largc cxplo.liol7 /lndcrwatcr: cx/Jt'rill/cnt and data response oE a layered halE-space in terms oE reElection and transmission properties oE the medium, for both up- and down-going waves. The method therefore includes all possible reflections and reverberations. The disadvantages are that Reflectivity is computationally expensive, CPU being proportional to the square of the number of layers; secondly, ray training support is required to help in the interpretation of wave arrivals. Reflectivity has already been used to model typical explosion/shallow sea scenarios (MacBeth 1985) appropriate to the North Sea. Shock waves from an underwater explosion are modified in both shape and wave velocity by the geometrical arrangement sediments and strata (including the sea) and physical properties of through which the waves propagate. After attempting theoretical modelling using Reflectivity, the need to compare observational data with theory became apparent. The need was for an experiment which would provide pressure data, for example, recorded at an array of sensors from a large explosion (say 2 ton) near to the Firth of Forth. This would serve to "calibrate" the modelling software and correlations between the improved modelling, using realistic sea-bed parameters, and observational data would be sought. Pressure observations would also allow evaluation of similitude equations used by Britt (1984) to model the maximum direct shock or free-field pressure wave. Improved modelling also relies on evaluation of realistic sea-bed parameters, because of the need to consider re flee t ions and shock wave/sea-bed interactions. Sea-bed sediment properties relevant to seismo-acoustic modelling, with the emphasis on the North Sea, have been reviewed by Allen (1988) . A simple structural seismic velocity-depth model of the Firth of Forth region, including the effect of sea-bed sediments on seismic propagation, has been obtained by MacBeth and Burton (1988) for the analysis of seismic surface waves generated by underwater explosions (in Kirkcaldy Bay, offshore Scotland). This model can be improved and extended into the North Sea using the seismic data obtained from the controlled explosion experiment described herein. The ultimate aim is to combine knowledge of the sea-bed sediment properties and 3
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Page 11 and 12: Appendix G: Picking list for travel
Page 13 and 14: Figures Fig. 2.1 Fig. 2.2 Fig. 2.3
Page 15: Fig. 7.3 Plot of travel time agains
Page 20 and 21: I. II 17 g ,. (/ 11 g (' ; II (1 ('
Page 22 and 23: LOllg ral/ge shock wa\'cs (rom a la
Page 25 and 26: .Ollg rallge shock \I'a\'('s (rolll
Page 28 and 29: I, (I 11 g /' a 11 g (' S " (> C k
Page 30 and 31: I,(/I/g rOl/ge sho('k lI'a\'es {ro/
Page 34 and 35: Long range shnc4 1I'0\'es frOIl1 a
Page 36 and 37: Long range shock waves from a large
Page 63 and 64: Browne, M.A.E., Palaeozoic Hargreav
Page 65 and 66: Lund, C-E., Roberts, R.G., Johlin,
Page 67 and 68: Turbitt, T., Browitt, C.V.A., Horga
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Table 2.4 Estimated upper bounds to
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Table 3.2 ARE pressure gauge calibr
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Table 3.4 SSP SPECIFICATIONS S500 a
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• (a) Geophone channels: (b) Hydr
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Table 4.1 Revised shot windows for
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Table 6.1 Geological characteristic
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* Table 7.2 Preliminary results fro
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Fig. 3.3 VHS - RECORDING CONFIGURAT
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System arrangement at BGS station N
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o o \() 92 o o
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6 7 8 9 14.00 - 14.10 15.20 - 15.30
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(2) Table log of deployaent of PUSS
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PUSS 2 (instrument 10) REDEPLOYED 2
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PUSS 5 (INSTRUMENT 13) REDEPLOYED 2
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12:32:45 12:33:30 12:35:15 12:36:00
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Standard deviation over 2 fixes: a
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No evidence of dragging. Yeight and
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3 ARE HYDROPHONE STRING Deployed fr
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Table 01: Paraaeters of preliminary
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Appendix 8: Data inventory Table 81
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Appendix 82 Inventory of PUSS data
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(b) 900lb shot All records start at
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Appendix P: Display of the data F1:
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.... w (J1 Fig. F.1.1 PUSS 10. RANG
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.... w en Fig. F .1.4 PUSS 13. RANG
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I-' ::. w Fig. F .1.9 PUSS 10, RANG
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t-' & Fig. F .1.14 BGS Sea Bottom P
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... U1 ....;j Fig. F.2.8 BGS Sea Ve
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.... en .... Fig. F.2.12 PUSS 09, R
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..... en w Fig. F.2.14 BGS Sea Bott
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I-' 01 01 Fig. F.2.17 BGS Sea Verti
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Fig. F.3.8 T enbmuir, 450OL.B SHOT,
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.... -..J w Fig. F.3.6 BGS Sea Bott
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Fig. F.3.15 PUSS 14. RANGE=85.291 K
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Start of record = 15:22:05.0 Filena
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BGS Sea bottom package: acceleratio
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Appendix H: Photographic record of
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Plate 1 Plate 2 Plate 3 •••
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Plate 7 Plate 8 Plate 9
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Plate 24 Plate 25
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Plate 32 Plate 33
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