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- Hydrologic models (2)
- Andesite -- Analysis (1)
- Atmosphere (1)
- Computer simulation (1)
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- Cryoconite -- Antarctica -- McMurdo Dry Valleys (1)
- Debris avalanches (1)
- Erosion -- Oregon -- Bull Run River Watershed (1)
- Flood control -- Economic aspects (1)
- Flood control -- Social aspects (1)
- Flood damage prevention (1)
- Flood forecasting -- United States -- Mathematical models (1)
- Geological mapping -- Eastern Oregon (1)
- Geomorphology -- Oregon -- Bull Run River Watershed (1)
- Glaciers -- Climatic factors -- Montana -- Glacier National Park (1)
- Glaciers -- Montana -- Glacier National Park -- Measurement -- 20th century (1)
- Glaciers -- Montana -- Glacier National Park -- Measurement -- 21st century (1)
- Glaciers -- United States (1)
- Glaciology (1)
- Hydration (1)
- Igneous differentiation (1)
- Igneous rocks -- Inclusions (1)
- Impact processes (1)
- Landslide hazard analysis (1)
- Landslides -- Oregon -- Linn County (1)
- Magmas -- Oregon -- Mount Hood -- Case studies (1)
- Mars (1)
- Mass-wasting (1)
- Meltwater (1)
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Articles 1 - 14 of 14
Full-Text Articles in Physical Sciences and Mathematics
From Probabilistic Socio-Economic Vulnerability To An Integrated Framework For Flash Flood Prediction, Sepideh Khajehei
From Probabilistic Socio-Economic Vulnerability To An Integrated Framework For Flash Flood Prediction, Sepideh Khajehei
Dissertations and Theses
Flash flood is among the most hazardous natural disasters, and it can cause severe damages to the environment and human life. Flash floods are mainly caused by intense rainfall and due to their rapid onset (within six hours of rainfall), very limited opportunity can be left for effective response. Understanding the socio-economic characteristics involving natural hazards potential, vulnerability, and resilience is necessary to address the damages to economy and casualties from extreme natural hazards. The vulnerability to flash floods is dependent on both biophysical and socio-economic factors. This study provides a comprehensive assessment of socio-economic vulnerability to flash flood alongside …
Ensemble Data Assimilation For Flood Forecasting In Operational Settings: From Noah-Mp To Wrf-Hydro And The National Water Model, Mahkameh Zarekarizi
Ensemble Data Assimilation For Flood Forecasting In Operational Settings: From Noah-Mp To Wrf-Hydro And The National Water Model, Mahkameh Zarekarizi
Dissertations and Theses
The National Water Center (NWC) started using the National Water Model (NWM) in 2016. The NWM delivers state-of-the-science hydrologic forecasts in the nation. The NWM aims at operationally forecasting streamflow in more than 2,000,000 river reaches while currently river forecasts are issued for 4,000. The NWM is a specific configuration of the community WRF-Hydro Land Surface Model (LSM) which has recently been introduced to the hydrologic community. The WRF-Hydro model, itself, uses another newly-developed LSM called Noah-MP as the core hydrologic model. In WRF-Hydro, Noah-MP results (such as soil moisture and runoff) are passed to routing modules. Riverine water level …
Measuring And Modeling Evolution Of Cryoconite Holes In The Mcmurdo Dry Valleys, Antarctica, Felix Jacob Zamora
Measuring And Modeling Evolution Of Cryoconite Holes In The Mcmurdo Dry Valleys, Antarctica, Felix Jacob Zamora
Dissertations and Theses
Cryoconite holes are vertical columns of meltwater within the shallow subsurface of glaciers. In the McMurdo Dry Valleys (MDV) of Antarctica cryoconite holes are a source of meltwater and harbor microbial communities in an otherwise arid environment with low biologic activity. The holes form as sediments on the ice surface, which are darker than the surrounding ice, are preferentially heated by solar radiation. The warm sediments melt the underlying ice and migrate downwards. An ice lid forms, isolating them from the below-freezing atmosphere enabling them to remain thawed. In this study, field observations, laboratory experiments, and numerical modeling are used …
Rock Glaciers Of The Contiguous United States: Spatial Distribution, Cryospheric Context, And Riparian Vegetation, Gunnar Forrest Johnson
Rock Glaciers Of The Contiguous United States: Spatial Distribution, Cryospheric Context, And Riparian Vegetation, Gunnar Forrest Johnson
Dissertations and Theses
Continental-scale inventories of glaciers are available, but no analogous rock glacier inventories exist. We present the Portland State University Rock Glacier Inventory (n = 10,343) for the contiguous United States, then compare it to an existing inventory of contiguous United States glaciers (n = 853), identifying geographic and climatic factors affecting the spatial distributions observed. At least one rock glacier is identified in each of the 11 westernmost states, but nearly 90% are found in just five; Colorado (n = 3889), Idaho (n = 1723), Montana (n = 1780), Utah (n = 834), and Wyoming (n = 849). Glaciers are …
Dynamics Of Magma Recharge And Mixing At Mount Hood Volcano, Oregon -- Insights From Enclave-Bearing Lavas, Molly Kathryn Ellowitz
Dynamics Of Magma Recharge And Mixing At Mount Hood Volcano, Oregon -- Insights From Enclave-Bearing Lavas, Molly Kathryn Ellowitz
Dissertations and Theses
Magma recharge events and subsequent mixing processes are understood to precede volcanic eruptions. Textural evidence of intrusion of hot, mafic magma into a cooler, rheologically locked silicic magma is commonplace. Solidified "blobs" of injected magma, called enclaves, are evidence of magma mixing, but the petrological and mechanical conditions during their formation are debated. Mount Hood, Oregon consistently erupts andesite bearing compositionally similar enclaves. These enclaves are evidence of mingling and mixing of two magmas. However, due to the compositional similarity between enclave and host lava (e.g. ~1-5 wt.% difference in SiO2), it is unclear whether the preserved enclaves …
Volcanic Glass As A Paleoenvironmental Proxy: Comparing Preparation Methods On Ashes From The Lee Of The Cascade Range In Oregon, Usa, Tessa Boe Carlson
Volcanic Glass As A Paleoenvironmental Proxy: Comparing Preparation Methods On Ashes From The Lee Of The Cascade Range In Oregon, Usa, Tessa Boe Carlson
Dissertations and Theses
Deuterium ratios (δD) of hydrated volcanic glass have been used to reconstruct paleoenvironments, although the reliability and proper sample preparation protocol have been debated. In this study, hydrated volcanic ash samples from the lee of the Cascades were prepared using two separate methods. Method 1 involves sonicating and rinsing samples with hydrochloric acid (HCl) followed by hand-selection of glass shards (125-212µm). Method 2 requires hydrochloric acid (HCl) and hydrofluoric acid (HF) abrasion as well as heavy liquid separation of shards (70-150µm). Method 2 produced more consistent results with decreased intra-replicate variability in both water content (-0.92 wt. %) and deuterium …
Using Repeat Terrestrial Laser Scanning And Photogrammetry To Monitor Reactivation Of The Silt Creek Landslide In The Western Cascade Mountains, Linn County, Oregon, Justin Craig Mccarley
Using Repeat Terrestrial Laser Scanning And Photogrammetry To Monitor Reactivation Of The Silt Creek Landslide In The Western Cascade Mountains, Linn County, Oregon, Justin Craig Mccarley
Dissertations and Theses
Landslides represent a serious hazard to people and property in the Pacific Northwest. Currently, the factors leading to sudden catastrophic failure vs. gradual slow creeping are not well understood. Utilizing high-resolution monitoring techniques at a sub-annual temporal scale can help researchers better understand the mechanics of mass wasting processes and possibly lead to better mitigation of their danger. This research used historical imagery analysis, precipitation data, aerial lidar analysis, Structure from Motion (SfM) photogrammetry, terrestrial laser scanning (TLS), and hydrologic measurements to monitor displacement of the Silt Creek Landslide in the western Cascade Mountain Range in Linn County, Oregon. This …
Quantifying Knickpoint Behavior And Erosion Mechanisms In An Urbanized Watershed, Bull Mountain, Washington County, Oregon, Max Gregory Bordal
Quantifying Knickpoint Behavior And Erosion Mechanisms In An Urbanized Watershed, Bull Mountain, Washington County, Oregon, Max Gregory Bordal
Dissertations and Theses
Quantifying spatial and temporal patterns of rapid channelized erosion, on human time scales, is critical to understanding its processes and their consequences. This investigation utilized field observations, repeat terrestrial laser scanning (TLS), and Structure-from-Motion photogrammetry (SfM) to document the size and retreat rates of a knickpoint, defined as a localized near-vertical reach of a fluvial channel, and its contribution to erosion, in an urbanizing landscape with a loess substrate. The Bull Mountain area, in Washington County, southwest of Portland, Oregon, is an ideal study area, offering a measurable knickpoint that translates the response of the rapid erosion throughout this transient …
Areal Extent And Volumes Of The Dinner Creek Tuff Units, Eastern Oregon Based On Lithology, Bulk Rock Composition And Feldspar Mineralogy, Teresa Rae Hanna
Areal Extent And Volumes Of The Dinner Creek Tuff Units, Eastern Oregon Based On Lithology, Bulk Rock Composition And Feldspar Mineralogy, Teresa Rae Hanna
Dissertations and Theses
The Dinner Creek Tuff erupted during a period of rhyolitic volcanism coeval to the flood volcanism associated with the Columbia River Basalt Group. The High Rock Caldera Complex, Lake Owyhee and McDermitt volcanic fields account for ~90% of the rhyolites erupted between 16.7-15.0 Ma. Situated at the northern end of the Lake Owyhee volcanic field, the Dinner Creek Tuff was originally mapped as a ~2,000 km2 single ignimbrite confined to the Malheur Gorge. Streck et al. (2015) correlated tuff outcrops previously mapped as generic Miocene welded tuff as well as local units such as the "Mascall" or "Pleasant Valley" …
Soil Phosphorus Characterization And Vulnerability To Release In Urban Stormwater Bioretention Facilities, Benjamin James Shetterly
Soil Phosphorus Characterization And Vulnerability To Release In Urban Stormwater Bioretention Facilities, Benjamin James Shetterly
Dissertations and Theses
Modern urban stormwater infrastructure includes vegetated bioretention facilities (BRFs) that are designed to detain water and pollutants. Phosphorus (P) is a pollutant in stormwater which can be retained in BRF soils in mineral, plant, and microbial pools. We explored soil properties and phosphorus forms in the soils of 16 operational BRFs in Portland, OR. Since soil hydrology can significantly impact P retention, we selected BRFs along an infiltration rate (IR) gradient. We conducted sequential fractionation and tests of P pools and measured P release in a subset of soils after drying and flooding samples for ten days. We hypothesized that …
The Wildcat Creek Tuff, Eastern Oregon: Co-Eruption Of Crystal-Poor Rhyolite And Fe-Rich Andesite With Implication For Mafic Underpinnings To Voluminous A-Type Rhyolites, Hillarie Jaye Sales
The Wildcat Creek Tuff, Eastern Oregon: Co-Eruption Of Crystal-Poor Rhyolite And Fe-Rich Andesite With Implication For Mafic Underpinnings To Voluminous A-Type Rhyolites, Hillarie Jaye Sales
Dissertations and Theses
The Wildcat Creek Tuff is a thin (~3-12 m), rhyolite to andesitic ash-flow tuff with a minimal extent of 1500 km2 in Malheur county, eastern Oregon. The previously undated tuff yielded a single crystal, anorthoclase 40Ar/39Ar age of 15.49±0.02 Ma and thus is closely related to mafic and silicic volcanism of the Columbia River Province. The tuff texturally stands out by its high proportion of co-mingled mafic inclusions appearing as dark, scoriaceous, and phenocryst-poor fragments, and their proportion dictate bulk tuff compositions ranging from rhyolite (74% SiO2) to andesite (59% SiO2). Glass analyses confirm …
Glacier Inventories And Change In Glacier National Park, Melissa Carrie Brett
Glacier Inventories And Change In Glacier National Park, Melissa Carrie Brett
Dissertations and Theses
Glacier National Park, in northwestern Montana, is a unique and awe-inspiring national treasure that is often used by the media and public-at-large as a window into the effects of climate change. An updated inventory of glaciers and perennial snowfields (G&PS) in the Park, along with an assessment of their change over time, is essential to understanding the role that glaciers are playing in the environment of this Park. Nine inventories between 1966 and 2015 were compiled to assess area changes of G&PS. Over that 49-year period, total area changed by nearly -34 ± 11% between 1966 and 2015. Volume change, …
Convective Transport Of Tropical Marine Boundary Layer Species Into The Upper Troposphere And Relation To Species Lifetime: In Situ Measurements And Global Model Simulation, Sofia M. Chelpon
Dissertations and Theses
This study investigates the influence of tropical deep convection on distribution of trace gasses in the tropical upper troposphere (UT) using data from the Convective Transport of Active Species in the Tropics (CONTRAST) Experiment conducted over the tropical western Pacific during January and February of 2014. Fifty-five chemical species measured during the CONTRAST campaign are analyzed with lifetimes ranging from less than a day to several years. The vertical profiles of these species suggest that they fall into three main groups delineated by their lifetime: 1) very long-lived trace gases demonstrating a nearly constant vertical structure, 2) intermediate lifetime species …
Differentiation In Impact Melt Sheets As A Mechanism To Produce Evolved Magmas On Mars, Ari Koeppel
Differentiation In Impact Melt Sheets As A Mechanism To Produce Evolved Magmas On Mars, Ari Koeppel
Dissertations and Theses
Asteroid bombardment contributed to extensive melting and resurfacing of ancient (> 3 Ga) Mars, thereby influencing the early evolution of the Martian crust. However, information about how impact melting has altered Mars’ crustal petrology is limited. Evidence from some of the largest impact structures on Earth, such as Sudbury and Manicouagan, suggests that some impact melt sheets experience chemical differentiation. If these processes occur on Mars, we expect to observe differentiated igneous materials in some exhumed rock samples. Some rocks observed in Gale crater are enriched in alkalis (up to 14 wt% Na2O + K2O) and …