Upper crustal poisson's ratios in the Colorado Plateau from multicomponent wide-angle seismic recording

Johnson, Roy A.; Hartman, Kenneth

doi:10.1029/gd022p0323

Cited by 9 publications

(4 citation statements)

References 15 publications

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“…Our borehole analysis confirmed that the uppermost part of the crystalline basement is likely weathered and/ or contains fluid-filled fractures. The presence of fluids can decrease the P-wave velocity of a rock unit by up to 20% (e.g., Goodwin and Thompson, 1988;Johnson and Hartman, 1991;Smithson et al, 2000;Healy et al, 2009), which can lead to strong impedance contrasts, and therefore, high-amplitude reflections that may be stronger than reflections from primary lithological changes (Hyndman and Shearer, 1989;Harjes et al, 1997). Fluid-filled fractures can cause scattering and crosscutting horizontal reflections (Ganchin et al, 1998).…”

Section: Sf1mentioning

confidence: 99%

Structural architecture and composition of crystalline basement offshore west Norway

et al. 2019

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Numerous studies have investigated the geodynamic history and lithological composition of the Proterozoic basement, Caledonian nappes, and Devonian extensional basins and shear zones onshore west Norway. However, the offshore continuation of these structures, into the northern North Sea, where they are suspected to have influenced the structural evolution of the North Sea rift, is largely unknown. Existing interpretations of the offshore continuation of Caledonian and Devonian structures are based on simple map-view correlations between changes in offshore fault patterns and pronounced onshore structures, without providing evidence for the presence, nature, and geometry of offshore, basement-hosted structures. By integrating three-dimensional (3-D) seismic, borehole, and onshore geological and petrophysical data, as well as two-dimensional (2-D) forward modeling of gravity and magnetic data, we reveal the structural architecture and composition of the crystalline basement on the Måløy Slope, offshore west Norway. Based on 3-D mapping of intrabasement reflection patterns, we identified three basement units that can be correlated with the Caledonian thrust belt, and the major Devonian Nordfjord-Sogn detachment zone, located only 60 km to the east, onshore mainland Norway. Similar to that observed onshore, offshore crystalline basement of the Proterozoic basement (Western Gneiss Region) and allochthons is folded into large-scale antiforms and synforms. These units are separated by the strongly corrugated Nordfjord-Sogn detachment zone. Our analyses show that different types of crystalline basement can be distinguished by their seismic reflection character, and density and magnetic properties. We speculate that the main causes of the observed intrabasement reflectivity are lithological heterogeneities and strain-induced structures such as shear and fracture zones. Our interpretation of the architecture of crystalline basement offshore west Norway has important implications for the location of the suture zone between Baltica and Laurentia.

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Section: Sf1mentioning

confidence: 99%

Structural architecture and composition of crystalline basement offshore west Norway

et al. 2019

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“…For initial results the reader is referred to: Benz and others (1990); Benz and McCarthy (in press); Howie (1991); Howie and others (1991); Parsons and others (1992); Johnson and Hartman (1991); Kohler and McCarthy (1990); McCarthy and Parsons (in press); Parsons and McCarthy (submitted), and Wolf and Cipar (1993).…”

Section: Geologic Backgroundmentioning

confidence: 99%

“…The University of Arizona deployed a 192-channel, 9.6-km-long recording spread between shotpoints 84 and 71 along the azimuth of the Colorado Plateau profile (Johnson and Hartman, 1991).…”

Section: Arizonamentioning

confidence: 99%

Data report for the PACE 1989 seismic refraction survey, northern Arizona

McCarthy¹,

Köhler²,

Criley³

1994

Open-File Report

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“…This can be partly overcome if S-wave information is also available (Christensen & Fountain 1975), as a more limiting set of petrological types can be constrained using the ratio of P-wave velocity to S-wave velocity (V,/V,), or equivalently Poisson's ratio. Previous studies of Poisson's ratio on a crustal scale have involved the use of high-resolution wide-angle reflection/refraction data (Sandemeier & Wenzel 1990 and references therein; Goodwin & McCarthy 1990;Johnson & Hartman 1991;Gohl & Pedersen 1995), and also P-wave and S-wave normal-incidence reflection data (Luschen, Nolte & Fuchs 1990;Ward & Warner 1991). Models of Poisson's ratio are typically determined using P-wave and S-wave velocity models produced with forward modelling methods (Gohl & Pedersen 1995), or by calculating the ratio of P-wave and S-wave traveltimes of prominent correlatable reflected phases (Goodwin & McCarthy 1990).…”

Section: Introductionmentioning

confidence: 99%

Determination of Poisson's ratio from pre-critical wide-angle seismic reflection data from the BABEL project

Law¹,

Snyder²,

Singh³

1995

Geophysical Journal International

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S U M M A R YThe pre-critical wide-angle seismic reflection data collected during the BABEL survey using multireceiver spreads contain high-amplitude P-wave and modeconverted S-wave reflected arrivals. The two phases can be partially separated and their signal-to-noise ratio emphasized by exploiting the multifold nature and the increased sensitivity of velocity analysis afforded by these data to produce zero-offset-corrected stacked sections. Using these sections, a method has been developed to derive estimates of Poisson's ratio by optimizing the cross-correlation of P-wave and S-wave arrivals, and hence to constrain petrological models of the crust sampled by these data. Although the apparently high degree of temporal and spatial resolution of reflected arrivals that are visible within the stacked sections must be reduced to achieve a satisfactory degree of correlation robustness, the results shed some light on crustal petrology, and concur with existing estimates of Poisson's ratio for the Baltic shield.

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Upper crustal poisson's ratios in the Colorado Plateau from multicomponent wide-angle seismic recording

Cited by 9 publications

References 15 publications

Structural architecture and composition of crystalline basement offshore west Norway

Structural architecture and composition of crystalline basement offshore west Norway

Data report for the PACE 1989 seismic refraction survey, northern Arizona

Determination of Poisson's ratio from pre-critical wide-angle seismic reflection data from the BABEL project

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