New Insights from Seismic Imaging Over the Youanmi Terrane, Yilgarn Craton,Western Australia

Ahmadi, Omid; Juhlin, Christopher; Gessner, Klaus

doi:10.1016/j.egypro.2014.10.356

Cited by 4 publications

(3 citation statements)

References 5 publications

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“…Other authors have used the same slant stack approach but with manually determined cross-dip values (Kim and Moon, 1992;Kim et al, 2014). A more simplistic approach is applying the cross-dip correction as a static shift to the whole trace (Wu et al, 1995;Rodriguez-Tablante et al, 2007;Lundberg and Juhlin, 2011;Ahmadi et al, 2014). However, this approach generally decreases the quality of all other reflections in the trace and is consequently mostly used for analyzing the cross-dips without applying the correction (Urosevic et al, 2007;Malehmir et al, 2009;Dehghannejad et al, 2010;Dehghannejad et al, 2012;Hedin, 2015).…”

Section: Previous Applications Of the Cross-dip Correctionmentioning

confidence: 99%

“…Since 2007, a couple of reflection seismic profiles over post-glacial faults have been recorded. In the case of the Pärvie (Juhlin et al, 2010;Ahmadi et al, 2014) and Suasselkä faults (Kukkonen et al, 2009;Abdi et al, 2015), the fault scarps could be linked with dipping reflections, but for the Burträsk fault (Juhlin and Lund, 2011), no reflection directly connected to the fault scarp was observed. However, Juhlin and Lund (2011) imaged a dipping reflection which they could indirectly link to the fault.…”

Section: Introductionmentioning

confidence: 99%

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The cross-dip correction as a tool to improve imaging of crooked-line seismic data: a case study from the post-glacial Burträsk fault, Sweden

Beckel

Juhlin

2019

Solid Earth

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Abstract. Understanding the development of post-glacial faults and their associated seismic activity is crucial for risk assessment in Scandinavia. However, imaging these features and their geological environment is complicated due to special challenges of their hardrock setting, such as weak impedance contrasts, often high noise levels and crooked acquisition lines. A crooked-line geometry can cause time shifts that seriously de-focus and deform reflections containing a cross-dip component. Advanced processing methods like swath 3-D processing and 3-D pre-stack migration can, in principle, handle the crooked-line geometry but may fail when the noise level is too high. For these cases, the effects of reflector cross-dip can be compensated for by introducing a linear correction term into the standard processing flow. However, existing implementations of the cross-dip correction rely on a slant stack approach which can, for some geometries, lead to a duplication of reflections. Here, we present a module for the cross-dip correction that avoids the reflection duplication problem by shifting the reflections prior to stacking. Based on tests with synthetic data, we developed an iterative processing scheme where a sequence consisting of cross-dip correction, velocity analysis and dip-moveout (DMO) correction is repeated until the stacked image converges. Using our new module to reprocess a reflection seismic profile over the post-glacial Burträsk fault in northern Sweden increased the image quality significantly. Strike and dip information extracted from the cross-dip analysis helped to interpret a set of southeast-dipping reflections as shear zones belonging to the regional-scale Burträsk Shear Zone (BSZ), implying that the BSZ itself is not a vertical but a southeast-dipping feature. Our results demonstrate that the cross-dip correction is a highly useful alternative to more sophisticated processing methods for noisy datasets. This highlights the often underestimated potential of rather simple but noise-tolerant methods in processing hardrock seismic data.

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Section: Previous Applications Of the Cross-dip Correctionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The cross-dip correction as a tool to improve imaging of crooked-line seismic data: a case study from the post-glacial Burträsk fault, Sweden

Beckel

Juhlin

2019

Solid Earth

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“…Other authors have used the same slant stack approach, but with manually determined crossdip values (Kim and Moon, 1992;Kim et al, 2014). A more simplistic approach is applying the crossdip correction as a static shift to the whole trace (Lundberg and Juhlin, 2011;Ahmadi et al, 2014). However, this approach generally decreases the quality of all other reflections in the trace and is consequently mostly used for analyzing the crossdips without applying the correction (Urosevic et al, 2007;Rodriguez-Tablante et al, 2007;Malehmir et al, 2009;Dehghannejad et al, 2010Dehghannejad et al, , 2012Hedin, 2015).…”

Section: Previous Applications Of the Crossdip Correctionmentioning

confidence: 99%

The crossdip correction as a tool to improve imaging of crooked line seismic data: A case study from the post-glacial Burträsk fault, Sweden

Beckel¹,

Juhlin²

2018

Preprint

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Abstract. Understanding the development of post-glacial faults and their associated seismic activity is crucial for risk assessment in Scandinavia. However, imaging these features and their geological environment is complicated due to special challenges of their hardrock setting, such as weak impedance contrasts, sometimes high noise levels and crooked acquisition lines. A crooked line geometry can cause time shifts that seriously de-focus and deform reflections containing a crossdip component. Advanced processing methods like swath 3D processing and 3D pre-stack migration can, in principle, handle the crooked line geometry, but may fail when the noise level is too high. For these cases, the effects of reflector crossdip can be compensated for by introducing a linear correction term into the standard processing flow. However, existing implementations of the crossdip correction rely on a slant stack approach which can, for some geometries, lead to a duplication of reflections. Here we present a module for the crossdip correction that avoids the reflection duplication problem by shifting the reflections prior to stacking. Based on tests with synthetic data, we developed an iterative processing scheme where a sequence consisting of crossdip correction, velocity analysis and DMO correction is repeated until the stacked image converges. Using our new module to reprocess a reflection seismic profile over the post-glacial Burträsk Fault in Northern Sweden increased the image quality significantly. Strike and dip information extracted from the crossdip analysis helped to interpret a set of southeast dipping reflections as shear zones belonging to the regional scale Burträsk Shear Zone (BSZ), implying that the BSZ itself is not a vertical, but a southeast dipping feature. Our results demonstrate that the crossdip correction is a highly useful alternative to more sophisticated processing methods for noisy datasets. This highlights the often underestimated potential of rather simple, but noise-tolerant methods, in processing hardrock seismic data.

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Seismic signatures of complex geological structures in the Cue-Weld Range area, Murchison domain, Yilgarn Craton, Western Australia

et al. 2016

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New Insights from Seismic Imaging Over the Youanmi Terrane, Yilgarn Craton,Western Australia

Cited by 4 publications

References 5 publications

The cross-dip correction as a tool to improve imaging of crooked-line seismic data: a case study from the post-glacial Burträsk fault, Sweden

The cross-dip correction as a tool to improve imaging of crooked-line seismic data: a case study from the post-glacial Burträsk fault, Sweden

The crossdip correction as a tool to improve imaging of crooked line seismic data: A case study from the post-glacial Burträsk fault, Sweden

Seismic signatures of complex geological structures in the Cue-Weld Range area, Murchison domain, Yilgarn Craton, Western Australia

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