Crustal Structure in the Surroundings of the KTB Drill Site as Derived from Refraction and Wide-Angle Seismic Observations

Gebrande, H.; Bopp, M.; Neurieder, P.; Schmidt, Tim

doi:10.1007/978-3-642-74588-1_8

Cited by 22 publications

(10 citation statements)

References 5 publications

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“…These include the wide-angle reflection seismics (e.g., GEBRANDE et al, 1989), crustal studies beneath the GRF-array (KRÜ GER and WEBER, 1992;KRÜ GER, 1994), upper mantle tomographic studies (FABER et al, 1986;PLOMVol. 151, 1998 EROVÁ and, as well as the SKS splitting measurements (KIND et al, 1985;SILVER and CHAN, 1988;VINNIK et al, 1994;BORMANN et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Seismic Anisotropy and Velocity Variations in the Mantle beneath the Saxothuringicum-Moldanubicum Contact in Central Europe

Plomerová

Babuška

Šı́lený

et al. 1998

Pure appl. geophys.

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We report on results of a passive seismic experiment undertaken to study the 3-D velocity structure and anisotropy of the upper mantle around the contact zone of the Saxothuringicum and Moldanubicum in the western margin of the Bohemian Massif in central Europe. Spatial variations of P-wave velocities and lateral variations of the particle motion of split shear waves over the region monitor changes of structure and anisotropy within the deep lithosphere and the asthenosphere. A joint interpretation of P-residual spheres and shear-wave splitting results in an anisotropic model of the lithosphere with high velocities plunging divergently from the contact of both tectonic units. Lateral variations of the mean residuals are related to a southward thickening of the lithosphere beneath the Moldanubicum.

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Section: Introductionmentioning

confidence: 99%

Seismic Anisotropy and Velocity Variations in the Mantle beneath the Saxothuringicum-Moldanubicum Contact in Central Europe

Plomerová

Babuška

Šı́lený

et al. 1998

Pure appl. geophys.

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“…The B and G reflections were attributed to the EB, but whether the R reflections R1 and R10 also belong to the EB remained undetermined. It is known from wide‐angle measurements, that the EB has a considerable lateral extension [ DEKORP Research Group , 1988; Gebrande et al , 1989]. Therefore, in this study we take the view that all signals with travel times between 3.2 and 4.8 s are reflections from the EB.…”

Section: Reflections From the Se1 Reflector And From The Erbendorf Bodymentioning

confidence: 99%

“…Several papers and KTB reports were devoted to presentation and first interpretations of the ISO‐89 3D data [e.g., Dürbaum et al , 1990, 1992; Stiller , 1991, 1992; Wiederhold , 1992], and several reflecting structures were identified in the depth range from about 2 to 15 km. The two most important ones are the Erbendorf body (EB), a high‐velocity structure that was already known from wide‐angle measurements [ DEKORP Research Group , 1988; Gebrande et al , 1989], and a new reflector, SE1, steeply dipping northeast in the upper crust. The SE1 is a fault‐like continuation of the Franconian Lineament, which at the surface trends roughly NW‐SE and separates sediments in the SW from crystalline rocks in the NE.…”

Section: Introductionmentioning

confidence: 99%

Seismic reflections from the crystalline crust below the Continental Deep Drilling Site KTB: Modeling and inference on reflector properties

2002

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[1] The three-dimensional (3-D) reflection-seismic data set ISO-89 3D was recorded near the deep borehole KTB in southeastern Germany. Reflections from the SE1 reflector and from the top of the Erbendorf body (EB) in the upper crystalline crust can be identified in 5-10% of the single-shot sections. The reflectors have been first identified in previous studies of stacked and migrated seismic data. In this paper the velocity and density variations of these two structures are estimated in a new way using true amplitude single-shot (vibroseis) data. The method uses the direct wave P g as a reference phase and models the amplitude ratios of the SE1 and EB reflections to P g . Modeling in this paper uses a combination of ray theory and the reflectivity method, and the SE1 and the top of the EB are assumed to be obliquely oriented 1-D structures. P g modeling shows that a depth-dependent velocity function within the uppermost crystalline basement explains the amplitudes and travel times of this phase with sufficient accuracy. The largest observed amplitude ratios SE1/P g and EB/P g are explained by laminated models with strong velocity contrasts and with reflection coefficients of magnitude 0.1-0.2 (SE1) and 0.05-0.15 (EB). The total thickness of the reflecting zones is less than $300 m. P g amplitude modeling requires low Q p factors (<100) to a depth of $1 km, whereas at larger depths, values of several hundred are necessary to keep the SE1 and EB velocity contrasts in realistic ranges. Both reflectors can be interpreted as cataclastic zones. For the SE1 this interpretation agrees with the view that it is a steeply dipping thrust fault which continues the tectonic Franconian Lineament into the upper crust. We assume that the EB is the fractured top of a high-velocity zone at depths below $10 km, known from earlier wide-angle measurements. Both reflectors have large weakly reflecting or nonreflecting parts. The SE1 is nonreflecting at the intersection with the KTB borehole.

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“…7). The display is confined to 100 channels and trace segments from 7 to 10 s including first breaks (F) and prominent wide-angle reflections (R), which originate from the well known but less understood Erbendorf body (e.g., GEBRANDE et al, 1989;HIRSCHMANN, 1996). Every shot was observed southeast in an offset range of approximately 42 to 58 km using a 200-channel equipment, giving a nominal fold of 16.…”

Section: Application To Field Datamentioning

confidence: 99%

“…Noisy parts are characterised by frequent colour fluctuations. The crustal segment at a depth of 8 to 13 km, the Erbendorf body (EB) (e.g., GEBRANDE et al, 1989), appears in both migrations as a dominant feature. 9) and slowness-driven isochrone migration (Fig.…”

Section: Application To Field Datamentioning

confidence: 99%

Focusing in Prestack Isochrone Migration Using Instantaneous Slowness Information

Tillmanns¹,

Gebrande²

1999

Pure appl. geophys.

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Prestack migration finds increasing application in processing crustal seismic data. However, less effort has been made to incorporate slowness information in the imaging process. The combination of slowness information with migration leads to an improved image in the depth domain, especially by reducing migration artefacts and noise. A slowness-driven isochrone migration scheme is introduced for migration of 2-D seismic data. Instantaneous slowness information p(x, t) is extracted from the data using correlation analysis in moving time and space windows. Slowness values resulting from spatial coherent energy (signal) and incoherent background noise are distinguished by the simultaneous evaluation of an instantaneous coherence criterion g(x, t). In slowness-driven isochrone migration this information is used for locally weighting the amplitude A(x, t) smearing on the isochrone surface. In particular, slowness p and coherence criterion g determine position and sharpness of a Gaussian weighting function. The method is demonstrated using two synthetic data examples and is subsequently applied to two deep crustal data sets, one wide-angle (along DEKORP4) and one steep-angle reflection seismic observation (KTB8506). Both data sets were collected in the surroundings of the KTB drill site, Oberpfalz, as part of the German DEKORP project.

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Crustal Structure in the Surroundings of the KTB Drill Site as Derived from Refraction and Wide-Angle Seismic Observations

Cited by 22 publications

References 5 publications

Seismic Anisotropy and Velocity Variations in the Mantle beneath the Saxothuringicum-Moldanubicum Contact in Central Europe

Seismic Anisotropy and Velocity Variations in the Mantle beneath the Saxothuringicum-Moldanubicum Contact in Central Europe

Seismic reflections from the crystalline crust below the Continental Deep Drilling Site KTB: Modeling and inference on reflector properties

Focusing in Prestack Isochrone Migration Using Instantaneous Slowness Information

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