3D Processing, Imaging and Interpretation of Dense Sub Bottom Profile Data Acquired in Avaldsnes and Hafrsfjord
Master thesis
Permanent lenke
https://hdl.handle.net/11250/3087787Utgivelsesdato
2023Metadata
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- Studentoppgaver (TN-IER) [147]
Sammendrag
This thesis addresses the challenges associated with conducting archaeological seismic surveys in shallow water and nearshore environments, focusing on the effects of dynamic elements such as wind, tide, and waves. These environments are known to contain a wealth of submerged archaeological remains, yet they are often overlooked due to the difficulties posed by their dynamic nature. While seismic geophysical methods are the preferred approach for archaeological prospection and investigations, the presence of dynamic elements hinders the acquisition of data in a regular grid pattern. The methodology employed to tackle these challenges involves creating a 3D grid of various sizes, tidal correction, interpolation and migration of the seismic dataset using the 3D grid. The proposed methodology was tested in Avaldsnes and Hafrsfjord - historically significant areas in Norway known to have shipwrecks. These locations serve as ideal test sites for evaluating the effectiveness of the methodology in addressing the problems posed by dynamic elements in shallow water and nearshore environments. Three 3D grid sizes were tested – 0.1 by 0.1 m, 0.25 by 0.25 m and 0.5 by 0.5 m - and two interpolation methods – cubic and Shepard’s interpolation – were tested. Results showed 0.1 by 0.1 m 3D grid size interpolated with Shepard’s method and migrated after showed the best seismic image and detail making identifying the shipwreck straightforward. The overall conclusion is that a 3D grid with small sizes, preferably 0.25 by 0.25 m or less, interpolated with Shepard’s method show the best seismic image for interpretation eliminating most of the problems caused by dynamic elements.