Tango, Gerard J. and Ali, Hassan B. (1987): Full wave theoretic modeling of comparative performance of deep sea floor and subsea floor hydrophone and geophone sensors

Leg/Site/Hole:
DSDP 76
DSDP 76 534
Identifier:
1991-013661
georefid

Creator:
Tango, Gerard J.
Nav. Ocean Res. and Dev. Act., United States
author

Ali, Hassan B.
author

Identification:
Full wave theoretic modeling of comparative performance of deep sea floor and subsea floor hydrophone and geophone sensors
1987
In: Anonymous, Expanded abstracts of the 57th annual international Society of Exploration Geophysicists meeting and exposition
Society of Exploration Geophysicists, International Meeting and Exposition, Tulsa, OK, United States
57
188-191
The full wave theoretic fast field/reflectivity method [Schmidt and Tango, Geophys. J. R. astro. Soc., March, 1986] is applied to determining the propagation characteristics governing reception of intermediate and long range low frequency seismo-acoustic signals, by horizontal and vertical arrays of hydrophones and geophones. Seismically equivalent stratigraphic models for fine-scale sediment P and S wave velocity are examined for a thickly sedimented DSDP site in the western North Atlantic, to determine the relative effects of P-S conversion, intrinsic attenuation, and stratigraphic layer transmission loss, on predicted signal strength level and coherence vs source receiver range, depth, and sensor depth. Synthetic CW reflection and transmission loss, in conjunction with synthetic OBS and VSP data, reveal an overall trend of monotonically decreasing signal level with depth, interrupted by localized zones of relatively lower (3-7 dB) signal loss, in agreement with synthetic and experimental borehole data from exploration seismic studies [Keho et al, 1984]. Within the seafloor, shear-specific loss effects may be as great as 10+ dB on the vertical component geophone. Only at isolated ranges does the vertical component exceed in signal level the horizontal component geophone or pressure hydrophone. The "optimum" subbottom depth for triaxial geophones and colocated hydrophones (i.e., minimum ambient noise and signal interference with direct and multiply-reflected water arrivals) is governed by the absolute level and directionality of ambient noise, seafloor boundary roughness, shear wave velocity, and depth to basement, or equivalent stratigraphic target zones.
English
Coverage:Geographic coordinates:
North:75.0000
West:-80.0000East: 20.0000
South:0.0000

Applied geophysics; Atlantic Ocean; Deep Sea Drilling Project; DSDP Site 534; geophones; geophysical methods; geophysical surveys; hydrophones; IPOD; Leg 76; marine methods; models; North American Atlantic; North Atlantic; seismic methods; surveys;

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