Vertical seismic profiling

Hardage, Bob A.

doi:10.1190/1.1487141

Cited by 115 publications

(63 citation statements)

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“…We processed data from 20 clamping depths. The depth interval between tool locations was most often 25 ±2 m (12 intervals), but ranged from 15 (3 intervals) to 31 m (1 interval) and averaged 23 m. Hardage (1983) discussed depth-spacing requirements to avoid spatial aliasing. At a spacing of 23 m, frequencies greater than 98 Hz are spatially aliased for seismic velocities greater than 4.5 km/s (the minimum sonic velocity, Unit IV).…”

Section: Methodsmentioning

confidence: 99%

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Seismic Stratigraphy in a Transverse Ridge, Atlantis II Fracture Zone

Swift¹,

Hoskins²,

Stephen³

1991

Proceedings of the Ocean Drilling Program

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During Ocean Drilling Program Leg 118, we conducted a vertical seismic profile in Hole 735B, a 0.5-km-deep borehole in 720 m of water on the eastern wall of the Atlantis II Fracture Zone, Southwest Indian Ridge. Seismograms were collected at 20 borehole depths, alternately using a water gun and then an air gun at each depth. The overall velocity is 6.5 km/s. The lowest interval velocities occur in the foliated gabbros (lithologic Unit I) and olivine gabbro-troctolite (Unit VI). We separated up-and down-going wavefields with frequency-wave number filtering and deconvolved the up-going field by spectral division using the down-going field at each receiver depth. The processed sections show irregular reflections from the base of the foliated gabbros (Unit 1, 50-70 mbsf) and from the Fe-Ti rich gabbro (Unit IV, 225-250 mbsf). We tentatively interpret coherent events at ~560 and 760-825 mbsf as reflections from Moho raised tectonically to shallow depths within the transverse ridge.

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Section: Methodsmentioning

confidence: 99%

“…We separated up-and down-going energy with a frequencywave number (F-K) filter (Hardage, 1983;Christie et al, 1983). This method assumes constant spacing of seismometer stations.…”

Section: Data Processingmentioning

confidence: 99%

Seismic Stratigraphy in a Transverse Ridge, Atlantis II Fracture Zone

Swift¹,

Hoskins²,

Stephen³

1991

Proceedings of the Ocean Drilling Program

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“…They are useful indicators of other components showing a steep reflection event but may be confused by the migration. The seismic record can be considerably improved, and interpretation facilitated by the use of two special techniques, the construction of synthetic seismograms, and the use of vertical seismic profiling (VSP) [38]. Synthetic seismograms are generated by the conversion of sonic and density data reflection coefficients.…”

Section: Sequence Stratigraphic Analysismentioning

confidence: 99%

Sequence Stratigraphy of Fluvial Facies: A New Type Representative from Wenliu Area, Bohai Bay Basin, China

Li¹,

Zhang²

2017

Seismic and Sequence Stratigraphy and Integrated Stratigraphy - New Insights and Contributions

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The application of sequence stratigraphy to the fluvial portion of sedimentary basin fills is most challenging, especially where the fluvial deposits under analysis are isolated or far away from coeval shorelines and marine influences. Taking the Wenliu Area as an example, this chapter aims at addressing researches about another type of river. High-resolution stratigraphic analysis of the lower second member of the Shahejie Formation of the W79 Block of Bohai Bay Basin (China) has revealed that the study area, previously interpreted as a shallow water delta system, actually originated in a subaerial setting with a distributional pattern. The base level fluctuations are mainly controlled by the regional tectonic setting. Active subsidence stages tend to make base level rising semi-cycles, while relative stable stages tend to make base level falling semi-cycles.

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“…In a zero-offset vertical seismic profile (Garperin, 1974;Hardage, 1983;Balch and Lee, 1984), a seismometer is clamped in a borehole at different depths, and the seismic wavefield generated from a source at the surface directly above the borehole is recorded. This technique bridges the observational gap between surface reflection profiling at frequencies of 10-200 Hz and borehole sonic logs at frequencies of 10-20 kHz.…”

Section: Introductionmentioning

confidence: 99%

Vertical Seismic Profile at Site 765 and Seismic Reflectors in the Argo Abyssal Plain

Bolmer¹,

Buffler²,

Hoskins³

et al. 1992

Proceedings of the Ocean Drilling Program

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The first Ocean Drilling Program (ODP) vertical seismic profile (VSP) experiment in a thick sedimentary section was conducted at Site 765 to measure compressional wave velocities and to correlate drilling results with seismic data. Measurements were performed through the cased portion of the hole between 186 and 915 mbsf using both air-gun and water-gun sources. Average velocities for the air-gun source were 1.967 km/s (284-915 mbsf), 1.815 km/s (186-284 mbsf), and 1.633 km/s (seafloor to 186 mbsf, extrapolated). Separation of the wavefield into upgoing and downgoing components by f-k filtering plus deconvolution of the upgoing wavefield produced good VSP records and revealed reflectors that correlate well with seismic profiles. These data were used to correlate the drilling results (lithologic units) with the seismic sequences at the drill site, which will be used to extrapolate the drilling results regionally. A weak sub-basement reflection at approximately 600 m into basement may correspond to the contact between pillow basalts and sheet flows. A comparison between VSP velocities, laboratory measurements, and sonic logs shows generally good agreement below about 420 mbsf.

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Vertical seismic profiling

Cited by 115 publications

References 0 publications

Seismic Stratigraphy in a Transverse Ridge, Atlantis II Fracture Zone

Seismic Stratigraphy in a Transverse Ridge, Atlantis II Fracture Zone

Sequence Stratigraphy of Fluvial Facies: A New Type Representative from Wenliu Area, Bohai Bay Basin, China

Vertical Seismic Profile at Site 765 and Seismic Reflectors in the Argo Abyssal Plain

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