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Disputation: Thea Sveva Faleide

Doctoral candidate Thea Sveva Faleide at the Department of Geosciences, Faculty of Mathematics and Natural Sciences, is defending the thesis Seismic imaging of faults and sedimentary systems of the Hoop region, Barents Sea – seismic facies, fault geometries and detection thresholds for the degree of Philosophiae Doctor.

Thea Sveva Faleide. Photo: Private

Thea Sveva Faleide. Photo: Private

The PhD defence and trial lecture are fully digital and streamed using Zoom. The host of the session will moderate the technicalities while the chair of the defence will moderate the disputation. It is possible to be present at the disputation in auditorium 1.

Trial lecture

As a recording:

3D evolution of normal fault systems from micro- to crustal scale 

Conferral summary (in Norwegian)

Seismikk kan avsløre geologiske strukturer i dypet, men tolkning av data kan by på utfordringer. I dette doktorgradsarbeidet er det fokus på seismiske avbildninger av forkastninger og sedimentære systemer basert på data av ulik oppløsning fra Hoop-området i det sørlige Barentshavet. Usikkerhet ved tolkning av dataene er vurdert – både objektive usikkerheter knyttet til begrensninger i foreliggende data, og subjektive usikkerheter knyttet til tolkerens bakgrunn og erfaringer.

Main research findings

Popular scientific article about Faleide’s dissertation:

Seismic imaging of faults and sedimentary systems of the Hoop region, Barents Sea – seismic facies, fault geometries and detection thresholds

Seismic data provide insight of geological structures in the subsurface, but there can be challenges to interpret the data. In this doctoral work geophysical and geological data are combined with seismic modelling to explore how structures and sedimentary systems can be imaged and mapped. Seismic data of different resolution, tied to borehole information, from the Hoop area in the southern Barents Sea are used to study limitations and uncertainties related to the datasets and the interpretation of the data.

The two first papers of this PhD work document the extent and age of a regional delta system that developed south from Svalbard to the Hoop area in the Cretaceous (approx. 125 million years ago). The depositional geometries of the past changed over geological time due to burial and deformation, and had to be reconstructed to establish a better understanding of the paleogeography and basin configuration in Early Cretaceous time. 

The last two papers in the doctoral study focus on seismic imaging of faults. In addition to the objective uncertainty associated with a limited seismic resolution quality, paper 3 deals with subjective uncertainties in relation to the interpreter's background and experience. A test panel of 20 geologists/geophysicists with different background interpreted the same dataset and their interpretations formed the basis for geological models tested with seismic modelling. In paper 4, the models are further developed with more detailed geometries and realistic properties related to faults/fractures including effects of gas (CO2) on seismic images.

Figure: Faults and clinoforms imaged in outcrop and seismic data
Faults and clinoforms imaged in outcrop and seismic data: (a) Single fault plane show what is typically interpreted in seismic data and (b) the actual fault zone with splays observed in outcrops (Photo credits: Haakon Fossen/ https://folk.uib.no/nglhe/StructuralGeoBookPhotos2ndEd.html). The photographs are mirrored, to match the faults in the thesis. Fault with splays imaged in (c) conventional and (d) high-resolution seismic data. (e) Clinoforms from outcrop data: Hanaskogdalen on Spitsbergen, from Helvetiafjellet Fm (Photo credit: Ivar Midtkandal). (f) Clinoforms imaged in high-resolution seismic data. Scales are not included. This figure illustrates the gap in resolution between outcrop and seismic data. Seismic data courtesy of TGS, WGP and VBPR. See larger version. Figure: Thea Sveva Faleide

Photo and other information:

Press photo: Thea Sveva Faleide, portrait; 500px. Photo: Private

Other photo material: Figure with description and credit as specified in the article above, size 1000px.

Published Oct. 15, 2021 10:48 AM - Last modified Nov. 1, 2021 1:00 PM