This thesis presents the results of three independent but related studies of aspects of the Mw 7.8 2012 Haida Gwaii earthquake, which was the second largest Canadian earthquake in recorded history. This event ruptured an area of roughly 150 by 40 km on a gently northeast-dipping thrust fault off the west coast of Moresby Island, British Columbia. This event was felt over 1600 km away from the epicentre, and produced tens of thousands of aftershocks. Adjacent to the mainshock fault plane is the Queen Charlotte Fault, the site of the largest event recorded in Canada: the 1949 Ms 8.1 strike-slip earthquake whose rupture extended as far south as this 2012 event and roughly as far north as an Mw 7.5 strike slip event which occurred on 5 January 2013. The 2012 thrust event was a surprise to some members of the seismological community as it ruptured a slab offshore of a major strike slip boundary. This earthquake therefore presents an excellent opportunity to constrain the tectonics and seismic hazard off the northwest coast of British Columbia. Herein a Coulomb stress transfer analysis is performed using finite fault models which incorporate both seismological and geodetic data. Static stress changes are projected onto optimally-oriented fault planes, determined using regional tectonic stresses in addition to mainshock stress; nodal planes, determined by aftershock centroid moment tensors; and onto the Queen Charlotte Fault. I find that aftershocks are generally consistent with Coulomb stress changes using optimal planes and known nodal planes, although the latter have slightly higher percentages of events consistent with triggering. I find that the Queen Charlotte Fault experienced stress changes greater than the empirically-determined threshold for triggering. This is particularly important as the southern extent of this fault is believed to lie in a seismic gap going back at least 116 years. With added stress from the mainshock and a lack of post-mainshock seismicity occurring in this seismic gap, it is a likely location for future earthquakes on this portion of the plate boundary. To obtain estimates of rupture parameters, an empirical Green's function technique and directivity analysis is performed. This method constrains rupture kinematics of the mainshock using systematic azimuthal variations in relative source time functions. My results indicate a rupture that progressed mainly to the northwest and updip. Subevent analysis confirms the existence of at least two subevents, with the first being roughly twice as large as the second. The results herein are similar to those found using finite fault inversion, but are better able to explain observed surface wave amplification at Alaskan seismic stations. My findings help support the idea that strong surface wave shaking may have resulted in delayed-onset dynamic triggering of the 2013 Craig event, through an unknown but intermediate mechanism that accounts for the two-month hiatus. Finally, an attempt was made to relocate all offshore aftershocks for this sequence by improving locations for events during a two-week ocean bottom seismometer deployment. This dataset includes a wider range of source-station azimuths and decreases the minimum source-receiver distance, relative to locations that only use land stations. My locations therefore represent the best-constrained depths for M greater than or equal to 3 offshore aftershocks occurring during the two-week deployment, and help constrain reasonable depth estimates from other relocation techniques. For events located using only ocean bottom seismometers I determine the time residual between observed and predicted phase arrivals at land stations to be used as a correction for all aftershocks recorded at land stations through the entire aftershock sequence. Although I was not able to find consistent time residuals I present suggestions for future implementations of this technique to this dataset, and discuss challenges associated with location of offshore earthquakes in regions with sparse regional seismic networks. All of these findings contribute to a more thorough understanding of this 2012 earthquake, as well as the tectonics of southern Haida Gwaii. I pay particular attention to identification of hazard within a seismic gap south of Moresby Island, and the northwest rupture directivity of the 2012 mainshock. / Graduate / 0373 / tiegan.hobbs@gmail.com

This research contributes to the emerging dialogue concerning power relationships and the alliances that are challenging current frameworks in an attempt to create positive change. Worldwide, local people in rural places are threatened by development paradigms and conflicting social, political, economic, and ecological values. Large-scale development, such as the Enbridge Northern Gateway Project (NGP), provide a tangible example of our failing systems and make the interplay of these elements palpable. Increasingly, communities are coalescing to challenge the current models and economically motivated agendas threatening Indigenous sovereignty and local lifeways. Central to these coalitions are Indigenous peoples who are aligning with non-Indigenous neighbours to renegotiate power relationships. This research examines these dynamic alliances and uses Haida Gwaii’s resistance to the NGP as an example of the formidable strength of community coalitions mobilized by intersecting values. To contextualize the NGP within the broader discourse, I problematize Canada’s environmental assessment process and consider how media portrays the growing resistance to the proposed project. Drawing on information presented through the environmental assessment, I analyze the main messages and shared values of Haida Gwaii citizens opposed to the NGP. This thesis focuses on this unanimous and galvanizing resistance, which is largely motivated by the reliance on local food sources and an embodied connection to Haida Gwaii shared by Island citizens. The continued denial of Aboriginal title and rights was inherent throughout this consideration and is an underlying theme throughout the analyses. / Graduate

Interest is growing worldwide among utility companies and governments of maritime countries in assessing the power potential of tidal streams. While the latest assessment for Canadian coastlines estimates a resource of approximately 42 GW, these results are based on the average kinetic energy flux through the channel. It has been shown, however, that this method cannot be used to obtain the maximum extractable power for electricity generation. This work presents an updated theory for the extractable power from a channel linking a bay to the open ocean. A mathematical model is developed for one-dimensional, non-steady flow through a channel of varying cross-section. Flow acceleration, bottom drag, and exit separation effects are included in the momentum balance. The model is applied to Masset Sound and Masset Inlet in Haida Gwaii, a remote island region, to determine the extractable power and its associated impacts to the tidal amplitude and volume flow rate through the channel.

One of the primary research interests at many late Pleistocene/early Holocene sites has been the transition from bifacial technology to a focus on microblade technology. Relationships between sites in Asia, Alaska, British Columbia, Haida Gwaii and elsewhere are frequently discussed with reference to the presence or absence of these technologies. As the focus has largely been on bifaces and microblades, other technologies have received considerably less attention. However, many of these more expedient technologies comprise the majority of assemblages found at any given site and reflect a substantial portion of technological practice and behavior. At the Richardson Island site, in southeastern Haida Gwaii, the stone tool assemblage is largely composed of unifacially manufactured tools that remain somewhat prevalent throughout the record of site activity. In this thesis, I begin my analysis with an exploration of the amount of standardization present in the unifacial tool types using cluster analysis. Following cluster analysis, the artifacts are discussed within the context of a behavioral model, taking the tools through a life history approach from raw material procurement to discard. Finally, this thesis focuses on technological change and continuity, tracing unifacial technologies through the detailed record of site activity at Richardson Island.

We present here a theory for the generation of mesoscale eddies, in the context of describing the generation of dipoles seen near the Queen Charlotte Islands in British Columbia. The Regional Ocean Modeling System (ROMS) is used to show dipoles forming from the coalescence of small headland eddies at Cape St. James. These headland eddies are formed by frictional generation of potential vorticity (PV) when the tide oscillates across the cape. Only 20% of the PV generated at the cape ends up in the headland eddies, with the remainder lost due to mixing of waters with PV of opposite signs. Coalescence of the headland eddies is achieved with a much higher efficiency - the PV contained in the final eddy is near 80% of the sum of that contained in the small eddies. Not all headland eddies coalesce. Coalescence of a positive PV eddy occurs only when the eddy is formed on a strong tidal flood followed by a weak ebb. Thus, a diurnal inequality in the tides is a requirement for coalescence. The eddies in the final dipole contain roughly equal amounts of PV; each has a radius of approximately 15 km and extends to nearly 100-m depth.

Microblades were a common feature of many lithic toolkits around the North Pacific during the late Pleistocene and early Holocene epochs. On Haida Gwaii, on British Columbia's North Coast, the earliest known microblades have been recovered from the Richardson Island site and date to approximately 8750 BP. Deep, well-defined stratigraphy at the site has provided a unique opportunity to observe a major technological shift as, between 8750 BP and 8500 BP, microblades gradually replaced the earlier bifacial toolkit and came to be a definitive aspect of the subsequent Moresby tradition technological suite. Several hypotheses have been presented, including microblades as a response to increasing raw material scarcity as a result of sea-level change, microblades as a technology imported by incoming Athapaskan speaking peoples, and microblades as an in situ design response to new subsistence practices brought about by ecological changes following the end of the last glaciation: a more durable, more deadly weapon well adapted to high-risk hunting activities. In this thesis I examine the possible reasons behind that shift in lithic technology. My analysis employs multiple lines of evidence to consider the theories. I examine the microblade assemblage and consider aspects of tool manufacture, use, and discard to determine how the microblades may have been used, and how they may relate to other microblade traditions in the region; I consider the paleoecology of southern Haida Gwaii during the early Holocene; and I use a set of controlled experiments to compare bifaces and slotted points in terms of durability and wound channel creation. / Graduate

One of the primary research interests at many late Pleistocene/early Holocene sites has been the transition from bifacial technology to a focus on microblade technology. Relationships between sites in Asia, Alaska, British Columbia, Haida Gwaii and elsewhere are frequently discussed with reference to the presence or absence of these technologies. As the focus has largely been on bifaces and microblades, other technologies have received considerably less attention. However, many of these more expedient technologies comprise the majority of assemblages found at any given site and reflect a substantial portion of technological practice and behavior. At the Richardson Island site, in southeastern Haida Gwaii, the stone tool assemblage is largely composed of unifacially manufactured tools that remain somewhat prevalent throughout the record of site activity. In this thesis, I begin my analysis with an exploration of the amount of standardization present in the unifacial tool types using cluster analysis. Following cluster analysis, the artifacts are discussed within the context of a behavioral model, taking the tools through a life history approach from raw material procurement to discard. Finally, this thesis focuses on technological change and continuity, tracing unifacial technologies through the detailed record of site activity at Richardson Island.

Subsequent to the Last Glacial Maximum (LGM), complex coastal response resulted from deglaciation, eustatic sea-level change, and a relatively thin, flexible lithosphere in the Queen Charlotte Islands (QCI) region of northwestern Canada. Presented here is an interdisciplinary study that combines the methodologies and schools of thought from geology, biology, and geography to address a research problem that spans these disciplines, specifically to illustrate the environment, temporal and spatial dimensions of isostatic crustal adjustment and the Late Quaternary coastline of the northeast Pacific continental shelf. Molluscan distribution, lithology, and published sub-bottom profiles are used to deduce sea-levels, outline the influence of glacially-induced crustal displacement, and reconstruct the paleoenvironment of the northeast Pacific Late Quaternary coastline, including the absence of ice and the presence of emergent coastal plains. These data are used to ascertain the region's suitability as a home for an early migrating coastal people. A series of paleogeographic maps and isostatic crustal displacement maps chart the sequence of evolving landscapes and display temporal changes in the magnitudes and extent of crustal flexure as a forebulge developed. The wave-length and amplitude of the glacially-induced forebulge supports thermal and refraction modeling of a thin (~25 km thick) lithosphere beneath Queen Charlotte (QC) Sound and Hecate Strait. Glacial ice at least 200 m thicker than present water depth began retreating from Dixon Entrance after 14,000 and prior to 12,640 14C years BP, generating 50 m of uplift in northern Hecate Strait. The position of the forebulge remained essentially constant after 12,750 14C years BP, implying a fixed ice-front and continued ice presence on the British Columbia (BC) mainland until ~10,000 14C years BP. A 3-dimensional model shows two ice-free terrains emerged: one extended eastward from the QCI, the other developed in QC Sound. By ~11,750 14C years BP a landbridge connected the BC mainland and QCI. Malacological evidence indicates a paucity of Arctic molluscan faima subsequent to glaciation, perhaps a consequence of shallow, narrowed straits, and the presence of ice sheets that interfered with ocean currents. Water temperature, sedimentation rates, turbidity, and photoperiod are factors that limited invertebrate colonization during the Late Pleistocene - Early Holocene. The oldest dated mollusc to colonize QCI region subsequent to LGM was Macoma nasuta at 13,210 14C years BP. Once habitat and sea-surface temperatures were conducive, rates of recolonization appear to be limited only by the availability of ocean currents to bring temperate pelagic larvae into the region from outlying areas. Between ~11,000 and 10,000 14C years BP the appearance of Clinocardium ciliatum and Serripes groenlandicus, concurrent with the disappearance, or significant reduction in number and productivity of temperate intertidal molluscs, indicates the onset of a short interval of cool sea-surface temperatures coincident with the Younger Dryas cooling event. Five molluscan species: Macoma incongrua, Musculus taylori (cf), Mytilimeria nuttallii, Tellina nucidoides, Mytilus edulis/Mytilus trossulus previously categorized as possessing a Recent geologic range were collected in sediments dating older than 10,000 14C years BP. Fossil mollusc shells indicate edible intertidal biomass densities well within commercially harvested levels on southern Moresby Island by 8,800 14C years BP, and on northern Graham Island by 8,990 14C years BP. The presence and productivity of nutritious intertidal molluscs indicates the QCI region had a suitable climate, possessed open ocean conditions, and provided subsistence resources for potential early humans subsequent to at least 13,210 14C years BP. Three-dimensional modeling shows subaerially exposed land that could have been inhabited by plants, animals, including coastal-migrating early humans. Early coastlines that have not been drowned, and which may harbour early archaeological sites, are identified along the western and northern coasts of QCI and the BC mainland. / Graduate

No description available.

This thesis describes the geomorphology and morphodynamics of two embayed, sandy, macrotidal beach-dune systems in the Cape St. James region of Gwaii Haanas National Park Reserve and Haida Heritage Site. Gilbert Bay beach is a small embayment with a southwest aspect that exhibits prograding dune ridges. Woodruff Bay beach, a larger system with a SE aspect, is characterized by large erosional scarps on the established foredune. Aspect to erosive conditions and embayment size control the distinct morphologic responses of these beach-dune systems. The morphodynamic regime at Cape St. James consists of high onshore sediment transport potential combined with an increasingly erosive water level regime that is forced by PDO and ENSO climatic variability events. Conceptual models of potential future responses of these beaches to sea level rise show a possible landward migration of up to 3.5 m at Gilbert Bay beach and up to 4 m at Woodruff Bay beach.