Hebert, David Lawrence2024-08-142024-08-1419821982https://hdl.handle.net/1828/18107In this thesis, electromagnetic induction in the Newfoundland region was studied using scaled laboratory analogue model and field station .measurements. Contour diagrams of the in-phase and quadrature-phase parts of the model magnetic field are used to show the field response to the bathymetry and complex coastlines in this region. The results indicate a large enhancement in the magnetic field occurs over the straits. This is due to the induced current being restricted to the strait. The maximum, anomalous magnetic field produced at the straits, found in analogue and numerical results, occurs when the depth of the strait is approximately 0.14 skin-depths. Magnetic field measurements show the deflection of induced current around capes which results in a large horizontal field seaward of the cape and a large vertical field at the cape coastline. An anomalous magnetic field is observed over the continental shelf edge for long periods, such as 900s; but not for short periods such as 100s. Comparison of single station and inter-station induction arrows shows that the difference between the two types of arrows occurs when an anomalous horizontal field is present. Over the ocean and at the coastlines, the single station in-phase arrows are smaller than the inter-station in-phase arrows, while just inland the single station in-phase arrows are larger than the inter-station in-phase arrows. The in­-phase arrows point towards the nearest and largest current density. The quadrature arrows reverse direction at the coastline for short periods, but this reversal is not evident for long periods. The model and field results differ considerably in the central region of Newfoundland. In this region, difference arrows, obtained by vector subtraction of model arrows from field arrows, point towards the major faults in the region. Model and field results also lead to the hypothesis of a horizontal conductivity contrast at depth in the central Newfoundland region.144 pagesAvailable to the World Wide WebThesis