Wide-angle, full waveform inversion with a sparse ocean-bottom seismometer dataset, imaging the Cyprus Arc from the Eratosthenes Seamount to the Hecataeus Rise.

Williams, Christopher (2020) Wide-angle, full waveform inversion with a sparse ocean-bottom seismometer dataset, imaging the Cyprus Arc from the Eratosthenes Seamount to the Hecataeus Rise. Masters thesis, Memorial University of Newfoundland.

[English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (180MB)

Abstract

Tectonophysicists working with wide-angle seismic reection and refraction data generally rely on tomographic inversion and forward modelling techniques to produce P-wave velocity models of the subsurface. Only recently, researchers have produced high-resolution P-wave velocity models using full-waveform inversion (FWI). However, they use ocean-bottom seismometer (OBS) datasets with a dense instrument spacing. This study revisits a sparsely acquired OBS dataset from the geologically complex Eastern Mediterranean to explore the feasibility of applying FWI to such a dataset. With frequency domain viscoacoustic FWI, we observe an adequate decrease in the objective function, suggesting that a high-resolution velocity model for the upper 15 km is obtainable through FWI with a typical OBS dataset. This decrease in the objective function does not preclude convergence to a local minimum. The recovered FWI model suffers from uncertainties in the starting model related to a complex geological environment. Cognizant of model uncertainties, we interpret an accretionary prism between the southern Eratosthenes continental block and the northern Hecataeus Rise from the final FWI model.

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