Imaging major Canadian sedimentary basins and their adjacent structures using ambient seismic noise (and other applications of seismic noise)

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dc.contributor.authorKuponiyi, Ayodeji Paul
dc.contributor.supervisorKao, Honn
dc.contributor.supervisorSpence, George D.
dc.date.accessioned2021-05-05T19:40:04Z
dc.date.available2021-05-05T19:40:04Z
dc.date.copyright2021en_US
dc.date.issued2021-05-05
dc.degree.departmentSchool of Earth and Ocean Sciences
dc.degree.levelDoctor of Philosophy Ph.D.en_US
dc.description.abstractOver a decade ago, it was discovered that the earth’s natural seismic wavefields, propagating as seismic noise, can be processed using correlation methods to produce surface waves, similar to those generated by earthquakes. This discovery represents a paradigm shift in seismology and has led to several tomographic studies of earth structures, at different scales and resolutions, in previously difficult-to-study areas around the world. This PhD dissertation presents research results on multi-scale and multi-purpose applications of ambient seismic noise wavefields under three topics: (1) Imaging of sedimentary basins and sub-basin structures in eastern and western Canada using ambient seismic noise, (2) Combining measurements from ambient seismic noise with earthquake datasets for imaging crustal and mantle structures, and (3) Temporal variation in cultural seismic noise and noise correlation functions (NCFs) during the COVID-19 lockdown in Canada. The first topic involved imaging the sedimentary basins in eastern and western Canada using shear wave velocities derived from ambient noise group velocities. The results show that the basins are characterized by varying depths, with maximums along the studied cross-sections in excess of 10 km, in eastern and western Canada. Characteristics of accreted terranes in eastern and western Canada are also revealed in the results. A seismically distinct basement is imaged in eastern Canada and is interpreted to be a vestige of the western African crust trapped beneath eastern Canada at the opening of the Atlantic Ocean. In western Canada, the 3D variation of the Moho and sedimentary basin depths is imaged. The thickest sediments in eastern Canada are found beneath the Queen Charlotte, Williston and the Alberta Deep basins, while the Moho is the deepest beneath the Williston basin and parts of Alberta basin and northern British Columbia. For the second topic, I worked on improving the seismological methodology to construct broadband (period from 2 to 220 s) dispersion curves by combining the dispersion measurements derived from ambient seismic noise with those from earthquakes. The broadband dispersion curves allow for imaging earth structures spanning the shallow crust to the upper mantle. For the third topic, I used ambient seismic data from the earlier stages of the COVID-19 pandemic to study the temporal variation of seismic power spectra and the potential impacts of COVID-19 lockdown on ambient NCFs in four cities in eastern and western Canada. The results show mean seismic power drops of 24% and 17% during the lockdown in eastern Canada, near Montreal and Ottawa respectively and reductions of 27% and 17% near Victoria and Sidney respectively. NCF signal quality within the secondary microseism band reached maximum before the lockdown, minimum during lockdown and at intermediate levels during the gradual reopening phase for the western Canada station pair.en_US
dc.description.scholarlevelGraduateen_US
dc.identifier.bibliographicCitationKuponiyi, A. P., Kao, H., van Staal, C. R., Dosso, S. E., Cassidy, J. F., and Spence, G. D. (2017), Upper crustal investigation of the Gulf of Saint Lawrence region, Eastern Canada using ambient noise tomography, J. Geophys. Res. Solid Earth, 122, 5208– 5227, doi:10.1002/2016JB013865en_US
dc.identifier.bibliographicCitationKuponiyi, A. P., Kao, H. (2021). Temporal Variation in Cultural Seismic Noise and Noise Correlation Functions during COVID‐19 Lockdown in Canada. Seismological Research Letters. 0895-0695. doi: https://doi.org/10.1785/0220200330en_US
dc.identifier.urihttp://hdl.handle.net/1828/12947
dc.languageEnglisheng
dc.language.isoenen_US
dc.rightsAvailable to the World Wide Weben_US
dc.subjectSeismologyen_US
dc.subjectAmbient Noiseen_US
dc.subjectSeismic Noiseen_US
dc.subjectTomographyen_US
dc.subjectAmbient Noise Tomographyen_US
dc.subjectSeismic Interferometryen_US
dc.subjectBayesian Statisticsen_US
dc.subjectTransdimensional Inversionen_US
dc.subjectSedimentary Basinen_US
dc.subjectWestern Canada Sedimentary Basinen_US
dc.subjectGulf of Saint Lawrenceen_US
dc.subjectMaritimes Basinsen_US
dc.subjectCOVID-19en_US
dc.subjectCOVID-19 Seismic Studiesen_US
dc.subjectdispersionen_US
dc.subjectsurface wavesen_US
dc.subjectRayleigh wavesen_US
dc.subjectsurface waves tomographyen_US
dc.titleImaging major Canadian sedimentary basins and their adjacent structures using ambient seismic noise (and other applications of seismic noise)en_US
dc.typeThesisen_US

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