Physical Sciences and Mathematics Commons^™

Modeling 21st Century Peak Flows In The Nooksack River Basin In Northwestern Washington State Using Dynamically-Downscaled Global Climate Model Projections, Evan A. Paul

WWU Graduate School Collection

The Nooksack River in northwestern Washington State provides freshwater for agriculture, municipal, and industrial use and serves as a vital habitat for endangered salmon, a resource that is of cultural and economic importance to the Nooksack Indian Tribe and the surrounding region. As more landscape becomes exposed to rain rather than snow and heavy winter precipitation events intensify (i.e., atmospheric rivers), peak flows and sediment delivery to streams will increase due to rapid runoff, resulting in salmon habitat degradation and increased flood risk. Thus, anticipating the effect of climate change on peak flows is crucial for salmon habitat restoration efforts …

Connections Between Eruption Style And Magmatic Reservoir Evolution: Insights From Augustine Volcano, Alaska, Usa, Mahinaokalani G. Robbins

WWU Graduate School Collection

At a single volcano, eruptive behavior can change through time as the plumbing system evolves. Augustine Volcano, a frequently active intermediate stratovolcano in the Alaska-Aleutian arc (USA), is an ideal setting to investigate magma reservoir processes due to its frequent modern and Holocene eruption history. Its most recent 2006 CE eruption included mixed effusive and moderately explosive (VEI 3) events and has been studied in detail. Proximal fall deposits from this eruption were generally mixed fine ash to lapilli with variable thickness, but typically ~5 cm on the island (Wallace et al., 2010). The Pre-contact “Tephra M” was deposited by …

A Mixed-Methods Study Of Geoscience Identity, Race/Ethnicity, And Gender In Senior Undergraduate Geoscience Majors, Willa Rowan

WWU Graduate School Collection

I conducted a mixed methods study of geoscience identity in undergraduate students to examine the cultural and social aspects of geoscience degree programs. White students are overrepresented in geoscience, and a priority of anti-racism efforts in the field is listening to the experiences of students who are Black, Indigenous, or people of color (BIPOC) to better inform equity and inclusion goals. Structural racism in geoscience pushes BIPOC students out of the field, and it can be better understood by studying socially constructed aspects of learning such as geoscience identity. This study is the first to measure geoscience identity with a …

Using Camera-Monitored Sediment Traps To Evaluate Sediment Availability And The Role Of Waves In Resuspending Seafloor Sediment, Bellingham Bay, Wa, Liam Horner

WWU Graduate School Collection

Understanding nearshore sediment budgets and processes is important for evaluating coastal hazards, habitats, and contaminant fate to enable informed decisions in coastal planning and management. I aimed to evaluate the role of waves in resuspending and redistributing sediments and by proxy contaminants in the urban/estuarine Bellingham Bay, and better understand the transport and rate of fluvial sediment moving through the nearshore. I integrated analyses using camera-mounted sediment traps, seafloor grain-size data, short-lived radioisotopes, and other fluvial, physical oceanographic, and wind data. I paired cameras with sediment traps, to identify the timing and rate of sedimentation on the seafloor at hourly …

Biomarker Study Of Bellingham Bay : Identifying How Urbanization Has Affected Carbon Storage And Eelgrass, Jess Shulman

WWU Graduate School Collection

Understanding sediment sources and fluxes throughout coastal zones is essential to evaluate shoreline stability, ecosystem health, and the potential for carbon storage. In Bellingham Bay, WA, like many developed coastal settings, urban areas have replaced forested cover and altered sediment fluxes, yet little is known of their offshore impacts. I analyzed n-alkanes, found in plant leaf waxes preserved in marine sediments of Bellingham Bay to characterize sediment sources and reconstruct changes in the relative contributions of eelgrass beds to sedimentary organic matter since pre-industrial times using a linear mixing model. Eight 2-meter-long cores were analyzed in order to determine how …

Reconstructing Wildfire Regime During The Warm Paleocene-Eocene Climate Using Molecular Biomarkers From The Chuckanut Formation In Northwest Washington, U.S.A., Alexandra Thompson

WWU Graduate School Collection

Wildfires are expected to increase in frequency and severity as climate changes in the Pacific Northwest of North America. To better understand the effect of warming climate on wildfire regimes, I present the first reconstruction of past wildfire frequency and severity during the Paleocene-Eocene transition in northwest Washington state, U.S.A. The Chuckanut Formation is a late Paleocene to Eocene sedimentary unit with a robust paleobotanical record showing the existence of subtropical forests in northwest Washington during the Paleocene, transitioning to a relatively cooler Eocene, dominated by temperate mixed forests. Geochemical records of environmental change coinciding with Paleocene-Eocene climatic change in …

Using Chemical Zoning In Minerals To Understand Magmatic Processes At Augustine Volcano, Alaska, Sloane Kennedy

WWU Graduate School Collection

The eruption behavior of a volcano is intrinsically linked to magmatic evolution. Augustine Volcano is an active stratovolcano in the Aleutian Arc (AK, USA), showing stratigraphic evidence that eruptions before 1,800 C.E. were more explosive, producing thick pumice deposits, compared to the six eruptions observed in the last 200 years. Tephra B, an understudied ~400-year-old pumice fall unit, represents the last more explosive style eruption at Augustine - making it ideal for studying how changes in magmatic evolution can result in changes in eruption style. For this thesis, I used textural zoning patterns and chemical variations (major and trace elements) …

U-Pb Zircon Geochronology And Structure Of Regional Blueschist Units In The Easton Metamorphic Suite, Northwest Cascades, Wa, Katherine Lang

WWU Graduate School Collection

The Easton metamorphic suite of the Northwest Cascades Thrust System (NWCS) is a well-preserved subduction accretion complex in Washington State. The regional blueschist units of the Easton metamorphic suite include the Mt. Josephine semi-schist, Darrington Phyllite, and Shuksan greenschist/blueschist and all are interpreted to have accreted after the onset of Jurassic subduction beneath North America. This study uses zircon U-Pb geochronology, structure, and field observations to test the regional correlations between units in the Easton metamorphic suite and address models for the timing of subduction accretion along the North American margin in the Late Jurassic – Early Cretaceous. The results …

Investigating Kīlauea’S 2018 Offshore Lava Emplacement Through Hydroacoustic Data, Olana Costa

WWU Graduate School Collection

The 2018 eruption of Kīlauea Volcano produced an unprecedented volume of lava, creating 3.5 km² of new land on Hawai`i’s Big Island (Soule et al., 2021). Lava expelled from the Ahu`aila`au vent (originally called Fissure 8) traveled ~13 km to where it entered the ocean. Over half of the lava erupted in 2018 was emplaced offshore where it produced four new submarine lava deltas (Soule et al., 2021). In response to the eruption, a network of 12 ocean-bottom seismometers (OBS) with attached hydrophones was deployed on Kīlauea’s submarine south flank. Ten of the instruments successfully recorded data from July …

Does Sediment Supply Impact The Threshold For Initial Sediment Motion In Natural, Gravel Bedded Streams?, Emily Loucks

WWU Graduate School Collection

Sediment transport in river channels control channel morphology, streamflow, and benthic ecosystems. Predicting sediment transport rates through a channel is required for sediment management for stream restoration and aquatic habitat assessment. The critical Shields stress (τ*_c), is a dimensionless parameter used in sediment transport models that characterizes the river bed surface shear stress required to initiate sediment motion. The τ*_c is typically assumed constant in transport models, yet compilations of field data have shown that τ*_c can vary wildly, causing sediment transport models to over- or under-predict fluxes by an order of magnitude or more. Understanding …

Paleomagnetic Determination Of Vertical Axis Block Rotation Near The Doty Fault In Southwestern Washington, Charles Linneman

WWU Graduate School Collection

In this paper I present the results of paleomagnetically derived vertical axis rotations (VARs) of sites in two different flows of the Columbia River Basalt (CRB) – the 16 Ma Sentinel Bluffs member of the Grande Ronde flow and the 12 Ma Pomona Member of the Packsack Lookout – near the Doty fault in southwestern Washington. In two field seasons, I collected 99 cores from 14 sites, 11 in the Grande Ronde flow and three in the Pomona member flow. Of the 227 specimens that I demagnetized, 212 had well-defined magnetic directions. Positive fold and reversal tests results confirm the …

Quantifying Channel Change Following Post-Fire Debris Flows In A Steep, Coastal Stream, Big Sur, California, Telemak Olsen

WWU Graduate School Collection

Debris flows commonly occur following wildfire in steep landscapes, introducing large volumes of sediment to downstream fluvial systems. Fire-related sediment supply perturbations impact channel morphology, and importantly, fragile aquatic and riparian ecosystems downstream of disturbance. The Big Creek watershed drains 57 km² of steep chaparral and coast redwood forest along California’s Central Coast. Streams in the Big Creek watershed typically exhibit step-pool/cascade morphology and serve as vital spawning habitat for anadromous Steelhead Trout (Oncorhynchus mykiss). In 2020, 97% of the Big Creek watershed burned in the Dolan Wildfire. In January 2021, an atmospheric river event triggered a series of …

Modeling The Effects Of Projected Climate Warming On Stream Temperatures In The Stillaguamish River Basin, Emily E. Smoot

WWU Graduate School Collection

The Stillaguamish River is a snow-and-rain mixed basin and the fifth largest river in the Puget Sound basin. Elevations in the 1700 km² Stillaguamish River basin reach roughly 2000 m and historically a snowpack is sustained above 1000 m. Snowmelt in the basin is important for sustaining spring and summer streamflow and buffering stream temperatures. Stream temperature increases are of significant concern because of the threatened Chinook salmon (Oncorhynchus tshawytscha) population.

I reexamined projected stream temperatures in the Stillaguamish River by forcing the coupled Distributed Hydrology Soil Vegetation Model and River Basin Model with dynamically downscaled meteorological …