Broadband Surface Wave Tomography of Ireland, Britain and Other Regions
APPROVED Over the last decades, seismic surface-wave studies have produced increasingly detailed images of the Earth s structure at a regional scale. In this study, we have tuned well-established techniques and when required implemented new ones in order to investigate regions in which important deb...
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| Format: | Doctoral or Postdoctoral Thesis |
| Language: | unknown |
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Trinity College Dublin. School of Natural Sciences. Discipline of Geology
2019
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| Online Access: | http://hdl.handle.net/2262/90896 https://tcdlocalportal.tcd.ie/pls/EnterApex/f?p=800:71:0::::P71_USERNAME:BONADIOR |
| Summary: | APPROVED Over the last decades, seismic surface-wave studies have produced increasingly detailed images of the Earth s structure at a regional scale. In this study, we have tuned well-established techniques and when required implemented new ones in order to investigate regions in which important debates are still ongoing, regarding the structure and the evolution of the Earth beneath them. Several studies suggested that the Paleogene uplift of parts of Britain and Ireland was caused by a lateral branch of the Iceland mantle plume, which played a fundamental role in the evolution of the North Atlantic Ocean over the past 60 M.y. Alternatively, among competing hypothesis, it was suggested that the uplift could be due to the far-field stress associated with the Alpine and Pyrenees Orogenies, with reactivation of old Variscan and Caledonian faults across Ireland and Britain. A major part of this study is aimed at gaining new insights into the seismic structure of the British Isles, which can help us answer these open questions. Teleseismic earthquakes and ambient noise, recorded at densely spaced seismic stations in the region, were used to determine the surface-wave dispersion across the British Isles and construct detailed images of the seismic structure beneath the area. The measurements, obtained using independent surface-wave analysis techniques (cross-correlation of teleseismic surface waves, multimode waveform fitting, and ambient noise interferometry), were applied to produce the first 3D shear-velocity model of the lithosphere and the asthenosphere of the entire region including Ireland, Britain, and the Irish Sea. The application of different methodologies yielded complementary frequency bands of the measurements, sensitive to different depths, from the shallow crust to the deep upper mantle. Abundant, newly available data was used to image the region with higher resolution than previously. The highly uneven station coverage resulted in a considerably irregular distribution of the measurements in the ... |
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