High-Resolution 3D Marine Seismic Investigation of Hedeby Harbour, Germany

Mueller, Christof; Woelz, Susanne; Kalmring, Sven

doi:10.1111/1095-9270.12011

Cited by 22 publications

(14 citation statements)

References 13 publications

(23 reference statements)

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“…In contrast to typical petroleum industry data, very‐high‐resolution seismic reflection acquisition methods are often technologically limited. Multi‐offset data are rare, even in the 2D case (e.g., Palamenghi et al ; Pinson et al ), while there are only a handful of very‐high‐resolution 3D data examples (Gutowski et al ; Plets et al ; Vardy et al , , ; Muller et al ; Mueller et al ). This lack of significant source‐receiver offsets allows the inversion process to be simplified, considering only the normal incident, plane‐wave case in the classical manner of Cooke and Schneider and Oldenburg et al .…”

Section: Inversion Approachmentioning

confidence: 99%

Deriving shallow‐water sediment properties using post‐stack acoustic impedance inversion

Vardy

2015

Near Surface Geophysics

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In contrast to the use of marine seismic reflection techniques for reservoir‐scale applications, where seismic inversion for quantitative sediment analysis is common, shallow‐waterm, very‐high‐resolution seismic reflection data are seldom used for more than qualitative reflection interpretation. Here, a quantitative analysis of very‐high‐resolution marine seismic reflection profiles from a shallow‐water (<50 m water depth) fjord in northern Norway is presented. Acquired using Sparker, Boomer, and Chirp sources, the failure plane of multiple local landslides correlates with a composite reflection that reverses polarity to the south. Using a genetic algorithm, a 1D post‐stack acoustic impedance inversion of all three profiles is performed, calibrating against multi‐sensor core logger (MSCL) data from cores. Using empirical relationships the resulting impedance profiles are related to remote sediment properties, including: P‐wave velocity; density; mean grain size; and porosity. The composite reflector is consistently identified by all three data sources as a finer‐grained (by one ϕ), lower density (c. 0.2 g/cm3 less than background) thin bed, with an anomalous low velocity zone (at least 100 m/s lower than background) associated with the polarity reversal to the south. Such a velocity contrast is consistent with an accumulation of shallow free gas trapped within the finer‐grain, less permeable layer. This study represents the first application of acoustic impedance inversion to very‐high‐resolution seismic reflection data and demonstrates the potential for directly relating seismic reflection data with sediment properties using a variety of commonly used shallow seismic profiling sources.

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Section: Inversion Approachmentioning

confidence: 99%

Deriving shallow‐water sediment properties using post‐stack acoustic impedance inversion

Vardy

2015

Near Surface Geophysics

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“…The problem inferred here is that 3D systems may be less sensitive to the faint signal variations which can, at times, signify archaeological features. For example, the fact that the SEAMAP-3D system, which was employed offshore from Haithabu in Haddeby Noor in 2007, did not distinguish the numerous landing piers we had mapped with an old analogue Chirp II in 1996 and furthermore verified by direct nondestructive groundtruthing could be a result of this resolution problem [23].…”

Section: Discussionmentioning

confidence: 98%

Chirping for Large-Scale Maritime Archaeological Survey: A Strategy Developed from a Practical Experience-Based Approach

Grøn¹,

Boldreel

2014

Journal of Archaeology

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Archaeological wrecks exposed on the sea floor are mapped using side-scan and multibeam techniques, whereas the detection of submerged archaeological sites, such as Stone Age settlements, and wrecks, partially or wholly embedded in sea-floor sediments, requires the application of high-resolution subbottom profilers. This paper presents a strategy for cost-effective, large-scale mapping of previously undetected sediment-embedded sites and wrecks based on subbottom profiling with chirp systems. The mapping strategy described includes (a) definition of line spacing depending on the target; (b) interactive surveying, for example, immediate detailed investigation of potential archaeological anomalies on detection with a denser pattern of subbottom survey lines; (c) onboard interpretation during data acquisition; (d) recognition of nongeological anomalies. Consequently, this strategy differs from those employed in several detailed studies of known wreck sites and from the way in which geologists map the sea floor and the geological column beneath it. The strategy has been developed on the basis of extensive practical experience gained during the use of an off-the-shelf 2D chirp system and, given the present state of this technology, it appears well suited to large-scale maritime archaeological mapping.

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“…() or Mueller et al . (, ) show very well resolved images (resolution of a few centimetres) of submarine archaeological targets, with very fast measurement progress. Nevertheless, this works only for the marine domain, where high frequency seismic sources can be applied.…”

Section: Discussionmentioning

confidence: 99%

Rayleigh‐wave Resonance Analysis: a Methodological Test on a Viking Age Pit House

Wilken

Wunderlich

Majchczack³

et al. 2015

Archaeological Prospection

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Seismic surface-waves may show amplitude resonances at certain frequencies depending on the thickness and elastic parameters of near-surface layers. We investigate if resonance frequencies of Rayleigh-waves, (seismic surface-waves polarized in the vertical plane) can be used to prospect archaeological remains of small-scale buildings such as pit houses. Our test site is a newly detected Viking age village on the island of Föhr (north Germany) where we concentrated on one typical pit house. The results from resonance analysis are compared with magnetic data, ground penetrating radar (GPR) and classical seismic refraction measurements. The method of Rayleigh-wave resonance mapping used in this paper is based on the idea that Rayleigh-wave oscillations on top of anthropogenic structures will show different resonances than on undisturbed soil. We perform spectral analysis of these oscillations to provide information related to the seismic site response. We process single vertical component recordings and map the change in resonance frequency that can be related to the archaeological objects. The test showed that the pit house can be mapped by Rayleigh-wave resonance analysis with a horizontal resolution of~0.6 m. Corresponding computations of the depth of the pit house agree with the results from GPR, magnetic modelling and refraction seismics. A modelling study helped to understand the connection between subsoil shear-wave velocity model and the signal generated by the pit house. The progress of seismic field measurement is slow compared to GPR and magnetometry. However, since seismic methods are based on elastic subsoil parameters, it can be applied in cases where magnetic contrasts are low or GPR fails because of high electromagnetic wave absorption.seismics (Models C, D, F to A, B, E), a change in topsoil velocity (Models E, F), a change in both velocities with the impedance contrast between the two layers kept constant (Model B) and a decrease in the velocity of the stiffer layer (Model C). The spectra show resonance frequencies at about 70 Hz for the Model 2 outside the pit house (Model D) and 45 Hz for Model 1 inside the pit house (Model A), which correlates well with the observation and thus supports the resonance frequency approach.The following effects can be observed: (a) Models A, B, C, and D show a strong maximum in the vertical component together with a sharpFigure 7. (a) Seismic shot gathers from the SH refraction reference profile (position see Figure 3). Picked first arrival times are indicated by blue and red dots. (b) Shear-wave velocity model obtained by the wavefront method. Numbers 1 and 2 indicate the two reference models that correspond to inside and outside the pit. For comparison, the measured magnetic signal of the profile and the location of the modelled prism are shown in (c). 2015. On the ability of geophysical methods to image medieval turf buildings in Iceland. Archaeological Prospection 22(3): 171-186.

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High-Resolution 3D Marine Seismic Investigation of Hedeby Harbour, Germany

Cited by 22 publications

References 13 publications

Deriving shallow‐water sediment properties using post‐stack acoustic impedance inversion

Deriving shallow‐water sediment properties using post‐stack acoustic impedance inversion

Chirping for Large-Scale Maritime Archaeological Survey: A Strategy Developed from a Practical Experience-Based Approach

Rayleigh‐wave Resonance Analysis: a Methodological Test on a Viking Age Pit House

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