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• 161. [Article] Small Tidal Channels Improve Foraging Opportunities for Calidris Shorebirds

  Estuarine intertidal habitats are heterogeneous, therefore migratory shorebirds are expected to forage in microhabitats where they can maximize their energy intake. Identifying proximate factors that migratory ...

  Citation × Citation Citation Abstract Copy Title: Small Tidal Channels Improve Foraging Opportunities for Calidris Shorebirds Author: Miller, Aileen K., de Rivera, Catherine E. Year: 2014 Estuarine intertidal habitats are heterogeneous, therefore migratory shorebirds are expected to forage in microhabitats where they can maximize their energy intake. Identifying proximate factors that migratory shorebirds use to accept or reject a particular habitat patch will help land managers make conservation and restoration decisions that provide the greatest benefits to shorebird populations during migration, a period of intense energy usage. We examined whether small semipermanent tidal channels were preferentially used by foraging Western Sandpipers (Calidris mauri) and Dunlins (C. alpina) during a spring migratory stopover in Bandon Marsh, an Oregon, USA, estuary. Further, we tested alternative hypotheses about how channels might be beneficial to shorebirds by examining infauna abundance, composition, and depth alongside channels compared with that in open mudflats. The densities of Western Sandpipers and Dunlins were at least 4 times higher along channels than in open mudflat habitats. Infauna along channels were twice as abundant as those in the surrounding mudflats, and infauna were generally found closer to the surface. Furthermore, sediment alongside channels required less than half the force to probe, probably increasing shorebirds' overall access to prey. We conclude that shorebirds selected microhabitats near channels because of the greater food abundance and availability. Additional evidence suggested that another microhabitat, patches of red algae (Gracilaria sp.), may also have conferred advantages on foraging shorebirds. Channels may be a valuable microhabitat to consider when selecting conservation areas for shorebirds, and maintaining channels (e.g., through maintaining natural hydrology and sedimentation patterns) should be considered in management practices. Title: Small Tidal Channels Improve Foraging Opportunities for Calidris Shorebirds Author: Miller, Aileen K., de Rivera, Catherine E. Year: 2014 Estuarine intertidal habitats are heterogeneous, therefore migratory shorebirds are expected to forage in microhabitats where they can maximize their energy intake. Identifying proximate factors that migratory shorebirds use to accept or reject a particular habitat patch will help land managers make conservation and restoration decisions that provide the greatest benefits to shorebird populations during migration, a period of intense energy usage. We examined whether small semipermanent tidal channels were preferentially used by foraging Western Sandpipers (Calidris mauri) and Dunlins (C. alpina) during a spring migratory stopover in Bandon Marsh, an Oregon, USA, estuary. Further, we tested alternative hypotheses about how channels might be beneficial to shorebirds by examining infauna abundance, composition, and depth alongside channels compared with that in open mudflats. The densities of Western Sandpipers and Dunlins were at least 4 times higher along channels than in open mudflat habitats. Infauna along channels were twice as abundant as those in the surrounding mudflats, and infauna were generally found closer to the surface. Furthermore, sediment alongside channels required less than half the force to probe, probably increasing shorebirds' overall access to prey. We conclude that shorebirds selected microhabitats near channels because of the greater food abundance and availability. Additional evidence suggested that another microhabitat, patches of red algae (Gracilaria sp.), may also have conferred advantages on foraging shorebirds. Channels may be a valuable microhabitat to consider when selecting conservation areas for shorebirds, and maintaining channels (e.g., through maintaining natural hydrology and sedimentation patterns) should be considered in management practices. Close

• 162. [Article] Passive Phase Separation of Microgravity Bubbly Flows Using Conduit Geometry

  The ability to separate liquid and gas phases in the absence of a gravitational acceleration has proven a challenge to engineers since the inception of space exploration. Due to our singular experience ...

  Citation × Citation Citation Abstract Copy Title: Passive Phase Separation of Microgravity Bubbly Flows Using Conduit Geometry Author: Jenson, Ryan M., Wollman, Andrew Paul, Weislogel, Mark M., Sharp, Lauren, Green, Robert, Canfield, Peter J., Klatte, Jörg, Dreyer, Michael E. Year: 2014 The ability to separate liquid and gas phases in the absence of a gravitational acceleration has proven a challenge to engineers since the inception of space exploration. Due to our singular experience with terrestrial systems, artificial body forces are often imparted in multiphase fluid systems aboard spacecraft to reproduce the buoyancy effect. This approach tends to be inefficient, adding complexity, resources, and failure modes. Ever present in multiphase phenomena, the forces of surface tension can be exploited to aid passive phase separations where performance characteristics are determined solely by geometric design and system wettability. Said systems may be readily designed as demonstrated herein where a regulated bubbly flow is drawn through an open triangular sectioned duct. The bubbles passively migrate toward the free surface where they coalesce and leave the flow. The tests clearly show container aspect ratios required for passive phase separations for various liquid and gas flow rates. Preliminary data are presented as regime maps demarking complete phase separation. Long duration microgravity experiments are performed aboard the International Space Station. Supplementary experiments are conducted using a drop tower. Title: Passive Phase Separation of Microgravity Bubbly Flows Using Conduit Geometry Author: Jenson, Ryan M., Wollman, Andrew Paul, Weislogel, Mark M., Sharp, Lauren, Green, Robert, Canfield, Peter J., Klatte, Jörg, Dreyer, Michael E. Year: 2014 The ability to separate liquid and gas phases in the absence of a gravitational acceleration has proven a challenge to engineers since the inception of space exploration. Due to our singular experience with terrestrial systems, artificial body forces are often imparted in multiphase fluid systems aboard spacecraft to reproduce the buoyancy effect. This approach tends to be inefficient, adding complexity, resources, and failure modes. Ever present in multiphase phenomena, the forces of surface tension can be exploited to aid passive phase separations where performance characteristics are determined solely by geometric design and system wettability. Said systems may be readily designed as demonstrated herein where a regulated bubbly flow is drawn through an open triangular sectioned duct. The bubbles passively migrate toward the free surface where they coalesce and leave the flow. The tests clearly show container aspect ratios required for passive phase separations for various liquid and gas flow rates. Preliminary data are presented as regime maps demarking complete phase separation. Long duration microgravity experiments are performed aboard the International Space Station. Supplementary experiments are conducted using a drop tower. Close

• 163. [Article] Population Dynamics of the Portland-Vancouver MSA

  This article offers a descriptive overview of population dynamics in the Portland-Vancouver Metropolitan Statistical Area (MSA). The MSA includes five of Oregon’s 36 counties–Clackamas, Columbia, Multnomah, ...

  Citation × Citation Citation Abstract Copy Title: Population Dynamics of the Portland-Vancouver MSA Author: Sprague, Webb, Picha, Emily Year: 2010 This article offers a descriptive overview of population dynamics in the Portland-Vancouver Metropolitan Statistical Area (MSA). The MSA includes five of Oregon’s 36 counties–Clackamas, Columbia, Multnomah, Washington, and Yamhill, as well as Clark and Skamania counties in the state of Washington (see Figure 1). (In 2007, the Portland-Vancouver-Beaverton MSA was redefined to include Skamania County in Washington. For the sake of comparability, we have therefore derived all historical data as if this definition has always applied. Because of this change, many of our historical numbers may have shifted since the last report on Oregon demography in the 2007 Metropolitan Briefing Book.) The article describes current trends for population growth; the effect of births, deaths, and migration on population growth; and how the age, sex, and ethnic composition of the population are changing. We concentrate on describing population trends rather than speculating on the causes of population change or making population predictions. An understanding of population dynamics can inform policy-making, and we hope we can provide a solid basis of understanding for decision-makers and community members in the Portland region. Title: Population Dynamics of the Portland-Vancouver MSA Author: Sprague, Webb, Picha, Emily Year: 2010 This article offers a descriptive overview of population dynamics in the Portland-Vancouver Metropolitan Statistical Area (MSA). The MSA includes five of Oregon’s 36 counties–Clackamas, Columbia, Multnomah, Washington, and Yamhill, as well as Clark and Skamania counties in the state of Washington (see Figure 1). (In 2007, the Portland-Vancouver-Beaverton MSA was redefined to include Skamania County in Washington. For the sake of comparability, we have therefore derived all historical data as if this definition has always applied. Because of this change, many of our historical numbers may have shifted since the last report on Oregon demography in the 2007 Metropolitan Briefing Book.) The article describes current trends for population growth; the effect of births, deaths, and migration on population growth; and how the age, sex, and ethnic composition of the population are changing. We concentrate on describing population trends rather than speculating on the causes of population change or making population predictions. An understanding of population dynamics can inform policy-making, and we hope we can provide a solid basis of understanding for decision-makers and community members in the Portland region. Close

• 164. [Article] Nano-structure Formation Driven by Local Protonation of Polymer Thin Films

  We report the creation of nano-structures via Dip Pen Nanolithography by locally exploiting the mechanical response of polymer thin films to an acidic environment. Protonation of cross linked poly(4-vinylpyridine) ...

  Citation × Citation Citation Abstract Copy Title: Nano-structure Formation Driven by Local Protonation of Polymer Thin Films Author: Maedler, Carsten, Graaf, Harald, Yan, Mingdi, La Rosa, Andres H. Year: 2009 We report the creation of nano-structures via Dip Pen Nanolithography by locally exploiting the mechanical response of polymer thin films to an acidic environment. Protonation of cross linked poly(4-vinylpyridine) (P4VP) leads to a swelling of the polymer. We studied this process by using an AFM tip coated with a pH 4 buffer. Protons migrate through a water meniscus between tip and sample into the polymer matrix and interact with the nitrogen of the pyridyl group forming a pyridinium cation. The increase in film thickness, which is due to Coulomb repulsion between the charged centers, was investigated using Atomic Force Microscopy. The smallest structures achieved had a width of about 40 nm. Different control experiments support our claim that the protonation is the reason for the swelling and therefore the formation of the structures. Kelvin probe force microscopy measurements suggest the presence of counter ions which compensate the positively charged pyridinium ions. We investigated the influence of the water meniscus on the structure formation by varying the relative humidity in the range from 5% to 60% for different dwell times. The diffusion of protons and counter ions is humidity-dependent and requires a water meniscus. Title: Nano-structure Formation Driven by Local Protonation of Polymer Thin Films Author: Maedler, Carsten, Graaf, Harald, Yan, Mingdi, La Rosa, Andres H. Year: 2009 We report the creation of nano-structures via Dip Pen Nanolithography by locally exploiting the mechanical response of polymer thin films to an acidic environment. Protonation of cross linked poly(4-vinylpyridine) (P4VP) leads to a swelling of the polymer. We studied this process by using an AFM tip coated with a pH 4 buffer. Protons migrate through a water meniscus between tip and sample into the polymer matrix and interact with the nitrogen of the pyridyl group forming a pyridinium cation. The increase in film thickness, which is due to Coulomb repulsion between the charged centers, was investigated using Atomic Force Microscopy. The smallest structures achieved had a width of about 40 nm. Different control experiments support our claim that the protonation is the reason for the swelling and therefore the formation of the structures. Kelvin probe force microscopy measurements suggest the presence of counter ions which compensate the positively charged pyridinium ions. We investigated the influence of the water meniscus on the structure formation by varying the relative humidity in the range from 5% to 60% for different dwell times. The diffusion of protons and counter ions is humidity-dependent and requires a water meniscus. Close

• 165. [Article] Stranding Mortality Patterns in California Sea Lions and Steller Sea Lions in Oregon and Southern Washington, 2006 to 2014

  As changing ocean conditions lead to declining fish stocks and movement of forage fish, sea lions on the Oregon coast are subject to the pressures of declining prey availability and increasing conflicts ...

  Citation × Citation Citation Abstract Copy Title: Stranding Mortality Patterns in California Sea Lions and Steller Sea Lions in Oregon and Southern Washington, 2006 to 2014 Author: Lee, Kessina Year: 2016 As changing ocean conditions lead to declining fish stocks and movement of forage fish, sea lions on the Oregon coast are subject to the pressures of declining prey availability and increasing conflicts with commercial and recreational fisheries. An analysis of strandings of California sea lions, Zalophus californianus, and Steller sea lions, Eumetopias jubatus, from 2006 to 2014, included cause of death, changing ocean conditions, and anthropogenic activity. Causes of death included disease, injury, and human interaction, such as gunshot wounds, fisheries net entanglements and boat strikes. Oregon and Washington strandings of California sea lions are primarily adult and subadult males that migrate north from California rookeries, while Steller sea lions are year-round residents and strandings are comprised of males and females of all ages. While the California sea lion population is currently at or near carrying capacity, the Eastern Pacific population of Steller sea lions was designated as Threatened under the Endangered Species Act until October 2013. Understanding impacts to these two pinniped species is vital to implementing effective management and conservation policies. Oregon and southern Washington strandings of California sea lions and Steller sea lions from 2006 to 2014 were analyzed spatially using the geographic information system (GIS), and temporally to identify possible correlations with prey availability and human interaction. Strandings were found to follow seasonal patterns from year to year: Steller sea lion strandings were highest from May to July, California sea lions peaked in September, October, and November. There was a correlation between significantly high numbers of strandings and the three largest commercial fisheries in Oregon: Chinook salmon, Coho salmon, and Dungeness crab. This analysis provides a format for continuing to monitor primary ecological and anthropogenic drivers of pinniped mortality in Oregon and southern Washington. Title: Stranding Mortality Patterns in California Sea Lions and Steller Sea Lions in Oregon and Southern Washington, 2006 to 2014 Author: Lee, Kessina Year: 2016 As changing ocean conditions lead to declining fish stocks and movement of forage fish, sea lions on the Oregon coast are subject to the pressures of declining prey availability and increasing conflicts with commercial and recreational fisheries. An analysis of strandings of California sea lions, Zalophus californianus, and Steller sea lions, Eumetopias jubatus, from 2006 to 2014, included cause of death, changing ocean conditions, and anthropogenic activity. Causes of death included disease, injury, and human interaction, such as gunshot wounds, fisheries net entanglements and boat strikes. Oregon and Washington strandings of California sea lions are primarily adult and subadult males that migrate north from California rookeries, while Steller sea lions are year-round residents and strandings are comprised of males and females of all ages. While the California sea lion population is currently at or near carrying capacity, the Eastern Pacific population of Steller sea lions was designated as Threatened under the Endangered Species Act until October 2013. Understanding impacts to these two pinniped species is vital to implementing effective management and conservation policies. Oregon and southern Washington strandings of California sea lions and Steller sea lions from 2006 to 2014 were analyzed spatially using the geographic information system (GIS), and temporally to identify possible correlations with prey availability and human interaction. Strandings were found to follow seasonal patterns from year to year: Steller sea lion strandings were highest from May to July, California sea lions peaked in September, October, and November. There was a correlation between significantly high numbers of strandings and the three largest commercial fisheries in Oregon: Chinook salmon, Coho salmon, and Dungeness crab. This analysis provides a format for continuing to monitor primary ecological and anthropogenic drivers of pinniped mortality in Oregon and southern Washington. Close

• 166. [Article] Bicrystallography in two dimensions: A graphical procedure and comparison of its results to experiments

  Three dimensional (3D) bicrystallography describes ideal structures of grain boundaries comprehensively at the atomic level as a function of the five macroscopic and two of the four microscopic parameters ...

  Citation × Citation Citation Abstract Copy Title: Bicrystallography in two dimensions: A graphical procedure and comparison of its results to experiments Author: Maas, Andrew M, Moeck, Peter Year: 2015 Three dimensional (3D) bicrystallography describes ideal structures of grain boundaries comprehensively at the atomic level as a function of the five macroscopic and two of the four microscopic parameters [1,2]. Free energy minimization of these structures leads to the real structure of these topologically distinct regions within crystals. These minimizations may either reduce the symmetries of ideal bicrystals or leave them intact. Since the symmetries of physical properties need to be compatible (by the Shubnikov-Curie and Curie-Minnigerode-Neumann principles [3]) with the symmetries of the atomic arrangements from which they arise, bicrystallography allows for predictions about which phenomena can occur in the 3D regions around grain boundaries. Because it provides atomically resolved (real space) images, the most popular structure analysis technique for grain boundaries [2] is Transmission Electron Microscopy (TEM). Since this is a projection technique, there is a need for the development of bicrystallography in two dimensions in order to make sense of TEM images in a straightforward way. We utilized a graphical procedure for 2D bicrystallography recently in the analysis of coincidence site lattice boundaries with [001] tilt axis in all cubic holohedral materials and present this procedure in this contribution in a didactic manner. We also reproduce from ref. [4] (with permission by the publisher) pairs of predicted and experimentally observed Σ13a (510) boundaries in SrTiO3 that are related by grain boundary migration, Fig. 1, in order to illustrate both the predictive power and the limitations of the bicrystallography approach. Title: Bicrystallography in two dimensions: A graphical procedure and comparison of its results to experiments Author: Maas, Andrew M, Moeck, Peter Year: 2015 Three dimensional (3D) bicrystallography describes ideal structures of grain boundaries comprehensively at the atomic level as a function of the five macroscopic and two of the four microscopic parameters [1,2]. Free energy minimization of these structures leads to the real structure of these topologically distinct regions within crystals. These minimizations may either reduce the symmetries of ideal bicrystals or leave them intact. Since the symmetries of physical properties need to be compatible (by the Shubnikov-Curie and Curie-Minnigerode-Neumann principles [3]) with the symmetries of the atomic arrangements from which they arise, bicrystallography allows for predictions about which phenomena can occur in the 3D regions around grain boundaries. Because it provides atomically resolved (real space) images, the most popular structure analysis technique for grain boundaries [2] is Transmission Electron Microscopy (TEM). Since this is a projection technique, there is a need for the development of bicrystallography in two dimensions in order to make sense of TEM images in a straightforward way. We utilized a graphical procedure for 2D bicrystallography recently in the analysis of coincidence site lattice boundaries with [001] tilt axis in all cubic holohedral materials and present this procedure in this contribution in a didactic manner. We also reproduce from ref. [4] (with permission by the publisher) pairs of predicted and experimentally observed Σ13a (510) boundaries in SrTiO3 that are related by grain boundary migration, Fig. 1, in order to illustrate both the predictive power and the limitations of the bicrystallography approach. Close

• 167. [Article] Carlton, OR: Economic and Demographic Profile

  The Carlton Post Office was founded in 1874 along the railroad stretching from Portland to the unincorporated settlement known as St. Joe’s. According to local lore, a Mr. Wilson Carl traveled to the big ...

  Citation × Citation Citation Abstract Copy Title: Carlton, OR: Economic and Demographic Profile Author: Portland State University. Northwest Economic Research Center Year: 2017 The Carlton Post Office was founded in 1874 along the railroad stretching from Portland to the unincorporated settlement known as St. Joe’s. According to local lore, a Mr. Wilson Carl traveled to the big city to ask for an intermediate stop in what became known as Carl’s town, and later Carlton. Located in the heart of Yamhill County, Carlton enjoys a lively tourism industry for a town of its size, buoyed up by the proliferation of farms and wineries that the mild climate invites. Carlton is a small town, with a population of just over two thousand. It had a median age slightly below that for Yamhill County and the state of Oregon in 2010, due to relative abundance in the youth cohorts, but a larger share of working-age population than that observed in comparable small towns in Oregon. The local economy is dominated by the wine industry, but a sizeable percent of the population in Yamhill County is employed in the Education and Health Services sector, as well. Carlton has an above-average net migration rate, compared to both Yamhill County and the state. This report will use data from a variety of state and federal sources to describe the economic and demographic attributes of the town, provide forecasts from a number of sources for several economic and demographic factors, and outline factors to track going forwards. While small towns can be difficult to analyze due to a paucity of local-level data, information on Yamhill County at large provides considerable insight. Additionally, this report will discuss recommendations for future implementations of the Carlton Satisfaction Survey, in order to provide the City with trackable indicators going forwards. Title: Carlton, OR: Economic and Demographic Profile Author: Portland State University. Northwest Economic Research Center Year: 2017 The Carlton Post Office was founded in 1874 along the railroad stretching from Portland to the unincorporated settlement known as St. Joe’s. According to local lore, a Mr. Wilson Carl traveled to the big city to ask for an intermediate stop in what became known as Carl’s town, and later Carlton. Located in the heart of Yamhill County, Carlton enjoys a lively tourism industry for a town of its size, buoyed up by the proliferation of farms and wineries that the mild climate invites. Carlton is a small town, with a population of just over two thousand. It had a median age slightly below that for Yamhill County and the state of Oregon in 2010, due to relative abundance in the youth cohorts, but a larger share of working-age population than that observed in comparable small towns in Oregon. The local economy is dominated by the wine industry, but a sizeable percent of the population in Yamhill County is employed in the Education and Health Services sector, as well. Carlton has an above-average net migration rate, compared to both Yamhill County and the state. This report will use data from a variety of state and federal sources to describe the economic and demographic attributes of the town, provide forecasts from a number of sources for several economic and demographic factors, and outline factors to track going forwards. While small towns can be difficult to analyze due to a paucity of local-level data, information on Yamhill County at large provides considerable insight. Additionally, this report will discuss recommendations for future implementations of the Carlton Satisfaction Survey, in order to provide the City with trackable indicators going forwards. Close

• 168. [Article] A Statistical Investigation of Lower Columbia River Water Temperature, 1915-2003

  The Columbia River is home to anadromous salmon populations that migrate upriver every year to spawn. These fish require cool water temperatures (Tw) to survive. In recent years, high summer Tw in the ...

  Citation × Citation Citation Abstract Copy Title: A Statistical Investigation of Lower Columbia River Water Temperature, 1915-2003 Author: Overman, Corina Christina Mae Year: 2017 The Columbia River is home to anadromous salmon populations that migrate upriver every year to spawn. These fish require cool water temperatures (Tw) to survive. In recent years, high summer Tw in the Columbia River has caused increased mortality of salmon. Different possible explanations for increased Tw include climate change, deforestation, and decreased summertime streamflow (Q) due to dams. In this study, robust linear regression models of Tw based on air temperature (Ta) and Q were developed to examine the change in Tw over time. The data was separated into an historical period (1938-1956) and a modern period (1977-2003). Seasonal regression models were used for May through October (summer) and November through April (winter) for each period. Comparison of these models showed that Tw has become less sensitive to recent atmospheric heating and cooling. By contrast, analysis suggested that Tw has become more sensitive to variations in Q. Of the 1.5ºC increase in maximum summertime Tw, approximately 1.3ºC was due to dams and reservoir management based on changes in regression coefficients and average Q. A smaller, 0.2ºC change was estimated to be caused by increasing Ta since the mid-20th century. While average maximum Tw has increased, both the statistical model and data suggest that the variability in Tw from its climatological average has decreased, probably due to reservoir management. Title: A Statistical Investigation of Lower Columbia River Water Temperature, 1915-2003 Author: Overman, Corina Christina Mae Year: 2017 The Columbia River is home to anadromous salmon populations that migrate upriver every year to spawn. These fish require cool water temperatures (Tw) to survive. In recent years, high summer Tw in the Columbia River has caused increased mortality of salmon. Different possible explanations for increased Tw include climate change, deforestation, and decreased summertime streamflow (Q) due to dams. In this study, robust linear regression models of Tw based on air temperature (Ta) and Q were developed to examine the change in Tw over time. The data was separated into an historical period (1938-1956) and a modern period (1977-2003). Seasonal regression models were used for May through October (summer) and November through April (winter) for each period. Comparison of these models showed that Tw has become less sensitive to recent atmospheric heating and cooling. By contrast, analysis suggested that Tw has become more sensitive to variations in Q. Of the 1.5ºC increase in maximum summertime Tw, approximately 1.3ºC was due to dams and reservoir management based on changes in regression coefficients and average Q. A smaller, 0.2ºC change was estimated to be caused by increasing Ta since the mid-20th century. While average maximum Tw has increased, both the statistical model and data suggest that the variability in Tw from its climatological average has decreased, probably due to reservoir management. Close

• 169. [Article] A Morphologic Proxy for Debris Flow Erosion With Application to the Earthquake Deformation Cycle, Cascadia Subduction Zone, USA

  In unglaciated steeplands, valley reaches dominated by debris flow scour and incision set landscape form as they often account for > 80% of valley network length and relief. While hillslope and fluvial ...

  Citation × Citation Citation Abstract Copy Title: A Morphologic Proxy for Debris Flow Erosion With Application to the Earthquake Deformation Cycle, Cascadia Subduction Zone, USA Author: Penserini, Brian D., Roering, Joshua J., Strieg, Ashley Year: 2017 In unglaciated steeplands, valley reaches dominated by debris flow scour and incision set landscape form as they often account for > 80% of valley network length and relief. While hillslope and fluvial process models have frequently been combined with digital topography to develop morphologic proxies for erosion rate and drainage divide migration, debris-flow-dominated networks, despite their ubiquity, have not been exploited for this purpose. Here, we applied an empirical function that describes how slope-area data systematically deviate from so-called fluvial power-law behavior at small drainage areas. Using airborne LiDAR data for 83 small (~ 1 km2) catchments in the western Oregon Coast Range, we quantified variation in model parameters and observed that the curvature of the power-law scaling deviation varies with catchment-averaged erosion rate estimated from cosmogenic nuclides in stream sediments. Given consistent climate and lithology across our study area and assuming steady erosion, we used this calibrated denudation-morphology relationship to map spatial patterns of long-term uplift for our study catchments. By combining our predicted pattern of long-term uplift rate with paleoseismic and geodetic (tide gauge, GPS, and leveling) data, we estimated the spatial distribution of coseismic subsidence experienced during megathrust earthquakes along the Cascadia Subduction Zone. Our estimates of coseismic subsidence near the coast (0.4 to 0.7 m for earthquake recurrence intervals of 300 to 500 years) agree with field measurements from numerous stratigraphic studies. Our results also demonstrate that coseismic subsidence decreases inland to negligible values > 25 km from the coast, reflecting the diminishing influence of the earthquake deformation cycle on vertical changes of the interior coastal ranges. More generally, our results demonstrate that debris flow valley networks serve as highly localized, yet broadly distributed indicators of erosion (and rock uplift), making them invaluable for mapping crustal deformation and landscape adjustment. © 2017 Elsevier B.V. Title: A Morphologic Proxy for Debris Flow Erosion With Application to the Earthquake Deformation Cycle, Cascadia Subduction Zone, USA Author: Penserini, Brian D., Roering, Joshua J., Strieg, Ashley Year: 2017 In unglaciated steeplands, valley reaches dominated by debris flow scour and incision set landscape form as they often account for > 80% of valley network length and relief. While hillslope and fluvial process models have frequently been combined with digital topography to develop morphologic proxies for erosion rate and drainage divide migration, debris-flow-dominated networks, despite their ubiquity, have not been exploited for this purpose. Here, we applied an empirical function that describes how slope-area data systematically deviate from so-called fluvial power-law behavior at small drainage areas. Using airborne LiDAR data for 83 small (~ 1 km2) catchments in the western Oregon Coast Range, we quantified variation in model parameters and observed that the curvature of the power-law scaling deviation varies with catchment-averaged erosion rate estimated from cosmogenic nuclides in stream sediments. Given consistent climate and lithology across our study area and assuming steady erosion, we used this calibrated denudation-morphology relationship to map spatial patterns of long-term uplift for our study catchments. By combining our predicted pattern of long-term uplift rate with paleoseismic and geodetic (tide gauge, GPS, and leveling) data, we estimated the spatial distribution of coseismic subsidence experienced during megathrust earthquakes along the Cascadia Subduction Zone. Our estimates of coseismic subsidence near the coast (0.4 to 0.7 m for earthquake recurrence intervals of 300 to 500 years) agree with field measurements from numerous stratigraphic studies. Our results also demonstrate that coseismic subsidence decreases inland to negligible values > 25 km from the coast, reflecting the diminishing influence of the earthquake deformation cycle on vertical changes of the interior coastal ranges. More generally, our results demonstrate that debris flow valley networks serve as highly localized, yet broadly distributed indicators of erosion (and rock uplift), making them invaluable for mapping crustal deformation and landscape adjustment. © 2017 Elsevier B.V. Close

• 170. [Article] Holocene History of Deep-Seated Landsliding in the North Fork Stillaguamish River Valley From Surface Roughness Analysis, Radiocarbon Dating, and Numerical Landscape Evolution Modeling

  Documenting spatial and temporal patterns of past landsliding is a challenging step in quantifying the effect of landslides on landscape evolution. While landslide inventories can map spatial distributions, ...

  Citation × Citation Citation Abstract Copy Title: Holocene History of Deep-Seated Landsliding in the North Fork Stillaguamish River Valley From Surface Roughness Analysis, Radiocarbon Dating, and Numerical Landscape Evolution Modeling Author: Booth, Adam M., LaHusen, Sean R., Duvall, Alison R., Montgomery, David R. Year: 2017 Documenting spatial and temporal patterns of past landsliding is a challenging step in quantifying the effect of landslides on landscape evolution. While landslide inventories can map spatial distributions, lack of dateable material, landslide reactivations, or time, access, and cost constraints generally limit dating large numbers of landslides to analyze temporal patterns. Here we quantify the record of the Holocene history of deep-seated landsliding along a 25 km stretch of the North Fork Stillaguamish River valley, Washington State, USA, including the 2014 Oso landslide, which killed 43 people. We estimate the ages of more than 200 deep-seated landslides in glacial sediment by defining an empirical relationship between landslide deposit age from radiocarbon dating and landslide deposit surface roughness. We show that roughness systematically decreases with age as a function of topographic wavelength, consistent with models of disturbance-driven soil transport. The age-roughness model predicts a peak in landslide frequency at ~1000 calibrated (cal) years B.P., with very few landslide deposits older than 7000 cal years B.P. or younger than 100 cal years B.P., likely reflecting a combination of preservation bias and a complex history of changing climate, base level, and seismic shaking in the study area. Most recent landslides have occurred where channels actively interact with the toes of hillslopes composed of glacial sediments, suggesting that lateral channel migration is a primary control on the location of large deep-seated landslides in the valley. Title: Holocene History of Deep-Seated Landsliding in the North Fork Stillaguamish River Valley From Surface Roughness Analysis, Radiocarbon Dating, and Numerical Landscape Evolution Modeling Author: Booth, Adam M., LaHusen, Sean R., Duvall, Alison R., Montgomery, David R. Year: 2017 Documenting spatial and temporal patterns of past landsliding is a challenging step in quantifying the effect of landslides on landscape evolution. While landslide inventories can map spatial distributions, lack of dateable material, landslide reactivations, or time, access, and cost constraints generally limit dating large numbers of landslides to analyze temporal patterns. Here we quantify the record of the Holocene history of deep-seated landsliding along a 25 km stretch of the North Fork Stillaguamish River valley, Washington State, USA, including the 2014 Oso landslide, which killed 43 people. We estimate the ages of more than 200 deep-seated landslides in glacial sediment by defining an empirical relationship between landslide deposit age from radiocarbon dating and landslide deposit surface roughness. We show that roughness systematically decreases with age as a function of topographic wavelength, consistent with models of disturbance-driven soil transport. The age-roughness model predicts a peak in landslide frequency at ~1000 calibrated (cal) years B.P., with very few landslide deposits older than 7000 cal years B.P. or younger than 100 cal years B.P., likely reflecting a combination of preservation bias and a complex history of changing climate, base level, and seismic shaking in the study area. Most recent landslides have occurred where channels actively interact with the toes of hillslopes composed of glacial sediments, suggesting that lateral channel migration is a primary control on the location of large deep-seated landslides in the valley. Close