Grays Harbor Research Articles

The signature of accumulated permanent uplift, northern Cascadia subduction zone

AbstractUplift of the overriding plate at a subduction zone denotes interseismic strain accumulation, which is subsequently released during a megathrust earthquake. Although most interseismic strain is thought to be released elastically, observations of uplifted coastal regions at subduction zones worldwide indicate that some strain may result in permanent uplift. The Grays Harbor and Willapa Bay (Washington, USA) coastal region of the Cascadia subduction zone hosts flights of marine terraces testifying to late Pleistocene rock uplift. Our new detailed mapping of the marine terraces recognizes nine new units, including estuarine and fluvial sediments. Luminescence dating, relative age based on soil maturity and terrace elevation, and an evaluation of previous ages from fossil shells collectively constrain the probable ages of three estuarine units to sea-level high stands during Marine Isotope Stages 5a, 5c, and 5e. We estimate an average uplift rate of 0.4 ± 0.1 mm/yr for the terraced estuarine units, consistent with other Pleistocene uplift and incision rates in Cascadia. When compared with observed interseismic vertical deformation, these rates suggest that about one-tenth of interseismic strain may become permanent. The values are permissible within the uncertainties of uplift based on regional estimates of interseismic vertical strain rates and of coseismic subsidence.

The Violence of Work: New Essays in Canadian and US Labour History ed. by Jeremy Milloy and Sangster Joan (review)

Reviewed by: The Violence of Work: New Essays in Canadian and US Labour History ed. by Jeremy Milloy and Sangster Joan James Naylor Milloy, Jeremy and Joan Sangster, eds.–The Violence of Work: New Essays in Canadian and US Labour History. Toronto: University of Toronto Press, 2021. 200 p. Discussions of violence in the workplace make one think of the latest headlines; in the wake of the COVID pandemic, the violence directed at health care workers looms large. Examples are not hard to come by. Stories of nurses being advised not to wear their scrubs on their way to their hospital shifts boggle the mind. A feature on the CBC Radio show White Coat, Black Art on the ways in which the quotidian violence in a big-city Emergency Room has been exacerbated by the multiple effects of the pandemic, and the opioid crisis, was sadly not surprising. These are, of course, “in-your-face” examples of workplace violence in a sector bearing the brunt of a combination of crises and very much under the spotlight. I was aware of the campaign by the Canadian Federation of Nurses’ Unions that declared “Violence is not part of the job” but, as they effectively acknowledge, it clearly is. Violence runs deeper in health care and far beyond. One of the contributions to this edited collection focuses on nursing: Sarah Jessup relates the story of the murder of Lori Dupont, a recovery room nurse in Windsor, Ontario, at the hands of her sexual harasser. At first glance, this is a case of intimate partner violence; when she rejected his advances, he killed her and himself. But it is very much a workplace story. The perpetrator was a doctor, and the hierarchies of hospitals are deeply entrenched and run along multiple lines of professional authority, gender, and management. What ensued, as Jessup articulately explains, was a struggle to recognize harassment and gender-based violence as an issue of workplace health and safety. We tend to look at violence as episodic and exceptional. Today, it is in health care and the pandemic. In the past, it may have been workers’ battles with police or mining disasters. But the editors and authors of this fine book explore a range of work experiences, past and present, to point out that violence pervades the world of work in many ways and for many reasons. And, to echo the nurses, it is far too often hidden or trivialized, becoming just “part of the job.” In realms which we may consider as having been particularly dangerous, such as sex work in early-nineteenth-century Montréal, violent encounters were multifarious as danger lurked, it seemed, from all directions. Mary Anne Poutanen explores how workplaces, homes, and the streets were places of danger from a range of clients, employers, authorities, and often their peers. They and other workers were embedded in a culture of violence. James Schmidt considers the violence perpetrated by workers themselves by examining Progressive Era reform schools in Iowa. He places the abuse of children within a longer history of corporal punishment where the limits of abuse were vague and shifting. As Schmidt notes, it is hard not to think of the abuse at Indian residential schools, rooted in both settler colonialism and settler notions of adult authority, and aimed at instilling, among other things, settler work habits. Chad Pearson further explores this legacy by drawing what might seem to be a tenuous connection between the antebellum wars to remove the Seminoles from Florida and the kidnapping—and forced relocation to an island near [End Page 228] Honduras!—of 13 leaders of a 1901 cigar workers’ strike in Tampa. The mastermind of the latter action was a leader of the anti-union Tampa “Citizens Committee” and historian (and enthusiast) of antebellum Florida society and the wars against the Seminoles. The language and goals of the two campaigns, 60 years apart, were remarkably similar. The West, of course, exists in American mythology as a particular place of violence and Aaron Goings’ story of Billy Gohl is fascinating. Gohl was a union leader in early-twentieth-century Grays Harbor, Washington, practising “militant, sometimes violent, forms of labour activism...

Pharmaceuticals and alkylphenols in transplanted Pacific oysters (Crassostrea gigas): Spatial variation and growth effects

Pharmaceuticals and personal care products in wastewater discharge can be stressors to estuarine species. We transplanted juvenile Pacific oysters at varying distances within sites near wastewater treatment plant outfalls or oyster aquaculture control sites to assess small scale spatial variation in contaminant uptake and oyster condition. Oysters were transplanted to sites in Coos and Netarts Bays, Oregon and Grays Harbor, Washington, then collected after 9 and 12 months. Two pharmaceuticals (miconazole and virginiamycin M1) were detected in spring samples and four alkylphenols (NP1EO, NP2EO, NP and OP) were detected in summer samples, with more frequent detections at wastewater sites. Contaminant concentrations were similar across site types, indicating that even in sparsely populated coastal areas (<25,000 in the watershed), shellfish are exposed to and uptake wastewater contaminants. Additionally, oyster condition was lower at wastewater sites compared to aquaculture sites, indicating a need to better understand whether contaminant exposure affects oyster condition.

Identifying local oil spill risk factors: An application of Hazard Identification within the International Maritime Organization Formal Safety Assessment framework in Washington State

Abstract Number 677002 Oil spills from commercial vessels are low probability, high consequence events that threaten economic, ecological, cultural, and natural resources. Washington State Department of Ecology Spill's Program (Ecology) has a robust risk assessment program that focuses on identifying and reducing oil spill risks to Washington waters. In 2017-2018, Ecology developed and implemented a novel application of the International Maritime Organization (IMO) Formal Safety Assessment process to lead a collaborative Hazard Identification for oil spill risk in Grays Harbor, Washington. This use of the IMO Formal Safety Assessment Process to assess oil spill risk was a first for Washington State and appears to be unique among US state governments. Working with area tribes, government agencies, and stakeholders, Ecology modified the IMO Formal Safety Assessment process to focus on local factors that could contribute to oil spill risks. Ecology facilitated structured brainstorming discussions during two workshops to complete Hazard Identification. Focusing on local factors fostered collaborative discussion among workshop participants, and allowed the process to benefit from local expertise about the characteristics of waterway and operational practices. The workshops resulted in the identification of 43 local factors related to oil spill risks, 34 recommendations to reduce risks based on current vessel traffic, and 10 recommendations to consider if vessel traffic increases in the future. The recommendations from this assessment are directly informing operations in Grays Harbor; in 2019, the Grays Harbor Safety Committee voted to adopt the risk assessment final report as an addendum to their Harbor Safety Plan. Ecology is also working with area tribes, government agencies, and stakeholders to review and prioritize the risk assessment recommendations with a goal of developing implementation plans for selected measures. This application of the IMO Formal Safety Assessment process represents a repeatable, scalable, and defensible method for conducting oil spill risk assessments. Ecology plans to use this process in other state waterways, and invites other organizations to consider adopting these methods. The presentation will walk through how to apply this process for localized waterway risk assessments and discuss best practices for success. Additionally, Ecology will discuss new risk analysis initiatives directed by the Washington State Legislature, including development of a quantitative model for evaluating oil spill risk and the potential effect of risk reduction measures.

Preliminary analysis of bivalve prey available to spring migrant Red Knots at Grays Harbor and Willapa Bay, Washington, USA

Preliminary analysis of bivalve prey available to spring migrant Red Knots at Grays Harbor and Willapa Bay, Washington, USA

Late-Holocene shoreline responses to competing shelf, bay, and beach accommodation spaces under conditions of relative sea level change, and the potential for future catastrophic beach retreat in the Columbia River Littoral Cell, Washington and Oregon, USA

The Columbia River Littoral Cell (CRLC) (160 km in length) provides opportunities to compare competing accommodation space relations under different conditions of relative sea level change. The CRLC system includes abundant littoral sand supply from the large Columbia River, late-Holocene prograded beach plains and barrier spits (0.5–5 km in width), two large marine-dominated estuaries (Willapa Bay and Grays Harbor), and a high-wave-energy inner-shelf. Littoral sand accumulation rates in prograded beach plains and barrier deposits are based on paleo-shoreline positions that are dated by great-earthquake catastrophic beach retreat scarps (n = 10) from 0.3 to 5.0 ka. The retreat scarp timelines are mapped in across-shore GPR transects (n = 79), yielding timeline-bounded polygons (n = 247). The polygons are evaluated for littoral sand volume and bounding ages, yielding volume accretion rates (m3 ka−1), which are summed for the four CRLC subcells; Clatsop Plains (27.4 × 106 m3 ka−1), Long Beach (19.8 × 106 m3 ka−1), Grayland Plains (15.9 × 106 m3 ka−1), North Beaches (11.7 × 106 m3 ka−1). Major submarine sinks of littoral sand, including the inner-shelf and large marine-dominated estuaries, are evaluated for increased littoral sand accommodation space that could result from potential future sea level rise of 1, 2 and 3 m during the next century or two. The estimated beach and nearshore sand erosion needed to fill the increased submarine accommodation space from a 2.0 m rise in relative sea level would result in averaged beach retreat values of ~0.7 km (Clatsop Plains), ~1.2 km (Long Beach), and ~ 1.3 km (Grayland Plains), about 30–50% larger than previous estimates based on the Brunn method. These catastrophic shoreline retreat distances (0.7–1.3 km) represent 25–50% of the present widths of prograded barrier spits and beach plains. They serve as warnings about future catastrophic beach erosion resulting from potential future SLR in other similar barrier spit and beach plain shorelines worldwide.

THE OTHER OREGON: PEOPLE, ENVIRONMENT, AND HISTORY EAST OF THE CASCADES by Thomas R. Cox

464 OHQ vol. 121, no. 4 the 1906 strike as well as his later demotion as union agent and ensuing bankruptcy, one wonders whether Gohl may have also made enemies within the union. While there is no reason to suspect him of mass murder, questions arise about whether he may have been as innocent of the murder for which he was convicted as the author concludes. The Port of Missing Men makes major contributions to both local history and the larger story of industrial capitalism. The fact that Gohl was never suspected of, much less charged with, the scores of Floater Fleet deaths exposes the myth of Billy the serial killer to be just that, myth. The real ghoul of Gray’s Harbor was capitalism and the ruthless shipping and timber magnates and double-dealing saloon and boardinghouse keepers whose standard business practices made poverty, degradation, injury, and death inevitable for the area’s laboring men and women. “The history of Billy Gohl and Grays Harbor,” Goings argues, “is one of class war, epitomizing such struggles around the globe” (p. 11) Nikki Mandell University of Wisconsin-Whitewater, emerita THE OTHER OREGON: PEOPLE, ENVIRONMENT, AND HISTORY EAST OF THE CASCADES by Thomas R. Cox Oregon State University Press, Corvallis, 2019. Illustrations, maps, notes, bibliography, index. 432 pages. $29.95 paper. In The Other Oregon, Thomas Cox takes on the daunting challenge of crafting a coherent and comprehensive history of Oregon east of the Cascade Mountains — Eastern Oregon, with a capital “E.” Cox is the right person for the job. To make sense of this big and diverse place, Cox turns to a field he essentially helped start: environmental history, which examines how people shape and are shaped by their environments . Interactions with the rugged environments of Eastern Oregon produced, Cox argues, both environmental transformations and the identity of this place and its people. Of this identity, Cox has personal experience; he was born and raised in Eastern Oregon, and those connections, as much as his professional expertise as an environmental historian, drive and shape this book. The Other Oregon is an effort to make sense of Eastern Oregon’s history and its identity for both readers and the author. The effort is largely a success for readers (the author will have his own assessment). Anyone looking for radical reinterpretations of Eastern Oregon’s history will be disappointed, but this book is meant for a broad, not exclusively academic, audience of Oregonians and Westerners wanting to understand Eastern Oregon. The Other Oregon is a necessary and thoughtful synthesis that incorporates the region into the history of Oregon and the American West, while at the same time acknowledging and appreciating what sets Eastern Oregon apart. The Other Oregon’s narrative and analysis unfolds through a generally chronological organization of different themes in human and environment relations as they evolved in Eastern Oregon. The book begins with an exploration of the area’s geological past, its varied climate, and its different ecological regions; upon this stage, Cox briefly introduces the Native peoples of the region and their uses of and adaptations to different environments. Then come Euro-Americans — fur trappers and traders, miners, cattle ranchers and sheep herders, grain farmers, loggers and timber barons, dryland homesteaders, and irrigation evangelists — and their myriad efforts to confront, profit from, and overcome environmental challenges and opportunities. Cox explains how these increasingly intensive extractive activities led to environmental degradation , including erosion, declining wildlife populations, and the spread of cheatgrass. By the mid twentieth century, this destruction prompted a turn toward conservation 466 OHQ vol. 121, no. 4 THE GREAT MEDICINE ROAD: NARRATIVES OF THE OREGON, CALIFORNIA, AND MORMON TRAILS, PART 2: 1849 edited by Michael L. Tate with Will Bagley, and Richard L. Rieck Arthur H. Clark Company, Norman, Oklahoma, 2015. Illustrations, maps, notes, bibliography, index. 328 pages. $39.95, cloth. THE GREAT MEDICINE ROAD: NARRATIVES OF THE OREGON, CALIFORNIA, AND MORMON TRAILS, PART 3: 1850–1855 edited by Michael L. Tate contributions by Kerin Tate, Will Bagley, and Richard L. Rieck Arthur H. Clark Company, Norman, Oklahoma, 2017. Illustrations, maps, notes, bibliography, index. 308 pages. $45.00 cloth. THE GREAT MEDICINE ROAD: NARRATIVES OF THE OREGON, CALIFORNIA...

Emulation as an approach for rapid estuarine modeling

Probabilistic flood hazard assessment is a promising methodology for estuarine risk assessment but currently remains limited by prohibitively long simulation times. This study addresses this problem through the development of an emulator, or surrogate model, which replaces the simulator (in this case the coupled ADCIRC+SWAN model) with a statistical representation that is able to rapidly predict estuarine variables relevant to flooding. Emulation of water levels (WLs), non-tidal residual, and significant wave height, is explored at Grays Harbor, Washington (WA) USA using Gaussian process regression. The effectiveness of the methodology is validated at various model simplification levels to determine where error is being sourced. Emulated WLs are found to be skillful when compared to over a decade of tide gauge observations (root mean square error, RMSE, <15 cm). The largest loss of skill in the method originates with ADCIRC+SWAN attempting to reproduce observations, even when the majority of relevant physics are included. Subsequent simplifications to the simulator (input reduction techniques) and the emulator itself are found to introduce a trivial amount of error (average increase in RMSE of 1 cm). Emulated WLs are also compared to spatially varying observations and found to be equally skillful throughout the estuary. An example emulation application is explored by decomposing the relative forcing contributions to extreme WLs across the study site. Results show a compound nature of extreme estuarine WLs in that all forcing dimensions contribute to extremes, with streamflow having the least influence and tides the largest. Overall the approach is shown to be both skillful and efficient at reproducing critical hydrodynamic variables, suggesting that emulation may play a key role in improving our ability to probabilistically assess flood risk in complex environments as well as being promising in a range of other applications.

NORTH JETTY COASTLINE EVOLUTION AND SHORELINE ENGINEERING, GRAYS HARBOR, WASHINGTON

This study was initiated by the Port of Grays Harbor and the City of Ocean Shores, WA to address ongoing shoreline erosion processes, and sedimentation at the Grays Harbor Federal Navigation Channel. The North Jetty at the entrance to Grays Harbor Estuary, WA was constructed at the beginning of last century (1907) and resulted in major regional changes to the coastline. During the first 40 years post-construction of the jetty, approximately ten miles of sandy beach shoreline, two miles wide north of the jetty, was created by natural sediment transport processes. The accreted land was the base for the creation of the City of Ocean Shores. Since that time the shoreline has been periodically altered by extreme erosion events.

ENVISIONING COASTAL FUTURES: EXPLORING ALTERNATIVE SCENARIOS FOR THE US PACIFIC NORTHWEST COASTLINE

Sea level rise (SLR), changing storminess patterns, and development have exposed coastal communities to chronic coastal change and flooding hazards. Several U.S. Pacific Northwest communities are at high risk from coastal hazards and local decision makers often lack tools for developing adaptive capacity to increase resilience, particularly under climate change. Several sectors (e.g., local community groups, emergency managers, and land use planners) have recently begun to define responses to perceived increases in the frequency and magnitude of coastal hazards. Here we describe the efforts of a group of Oregon State University researchers and students, outreach specialists, and coastal community members in both Tillamook County, OR and Grays Harbor County, WA who are assessing climate change impacts and associated evolving community and ecosystem resilience.

Between-year variation in the timing of peak passage of spring migrant Red Knots at Grays Harbor, Washington, USA

Between-year variation in the timing of peak passage of spring migrant Red Knots at Grays Harbor, Washington, USA

Further investigation of green sturgeon (Acipenser medirostris) distinct population segment composition in non-natal estuaries and preliminary evidence of Columbia River spawning

Green sturgeon (Acipenser medirostris) is a highly migratory, marine oriented species that congregates in non-natal estuaries during summer and early fall. Individuals from the threatened Southern Distinct Population Segment (SDPS) and non-listed Northern Distinct Population Segment (NDPS) regularly co-occur in non-natal estuaries including the Columbia River estuary, Willapa Bay, and Grays Harbor in relative proportions not explained by abundance or distance from natal river. We used genetic markers to assign green sturgeon sampled in these estuaries from 2010 to 2012 to distinct population segments (DPS). We then examined interannual differences in DPS composition among estuaries. Fork length distributions were compared between SDPS and NDPS green sturgeon to determine whether size varied within and among DPSs and estuaries. The majority of green sturgeon sampled in the Columbia River estuary and Willapa Bay were assigned to the SDPS, while we assigned nearly even DPS proportions to our Grays Harbor samples. NDPS green sturgeon were significantly smaller than those originating from the SDPS within and among estuaries. We used these findings to develop several hypotheses about the mechanisms that may lead to specific patterns of non-natal estuary use. Genetic markers also assigned a single age-0 green sturgeon sampled in the Columbia River to the NDPS, although our analyses suggest that this individual’s parents may not have originated from known NDPS spawning populations. Because the Columbia River may serve as alternative spawning habitat for green sturgeon as climate change occurs, we recommend monitoring the Columbia River more closely for further evidence of green sturgeon spawning.

Distinguishing offshore bird hunting from beach scavenging in archaeological contexts: The value of modern beach surveys

Determining whether seabirds recovered from coastal shell middens were obtained via active hunting or scavenging of beached carcasses is a challenge for archaeologists. Traditional methods have included analyzing skeletal part frequencies, abundance, age profiles, and contextual evidence. The assumption has been made, based on limited biological data, that an assemblage of carcasses scavenged from the beach will have more wing elements, and fewer legs and heads. Few studies, however, have embraced modern beaching data to verify this assumption and assess the potential faunal resources available for scavenging. We analyze the skeletal part representation of modern beached birds observed by the Coastal Observation and Seabird Survey Team (COASST), comparing the COASST dataset to two idealized hypotheses used by archaeologists: the human scavenging hypothesis (wings only are recovered, while heads and legs are absent) and the human hunting hypothesis (all body parts are found in equal proportions). Finally, we apply these results to analysis of the bird remains from the Minard site (45-GH-15), a late Holocene coastal site in Grays Harbor, Washington. We find that contemporary beached bird data are closer to replicating the human hunting hypothesis as compared to the human scavenging hypothesis, as >75% of the 19,599 carcasses in the COASST dataset had a combination of head, wings and legs. This result, and the similarity in taxonomic distribution between our contemporary beached bird data and Minard assemblage, suggests that indigenous peoples may have used scavenging as a viable means of resource acquisition in the past. Use of contemporaneous beached bird data may provide zooarchaeology with a statistically defensible baseline of information on the phenology, abundance and condition of bird carcasses.

Assessing the risk to green sturgeon from application of imidacloprid to control burrowing shrimp in Willapa Bay, Washington--Part II: controlled exposure studies.

The activities of 2 species of burrowing shrimp have a negative impact on the growth and survival of oysters reared on intertidal mudflats in Willapa Bay and Grays Harbor, Washington (USA). To maintain viable harvests, oyster growers proposed the application of the neonicotinoid insecticide imidacloprid onto harvested beds for the control of burrowing shrimp. In test applications, water column concentrations of imidacloprid were relatively low and dissipated rapidly. The foraging activities of the green sturgeon (listed in the US Endangered Species Act) could result in exposure to higher, more sustained imidacloprid concentrations within sediment porewater and from the consumption of contaminated shrimp. Controlled experiments were conducted using surrogate white sturgeon to determine acute and chronic effect concentrations, to examine overt effects at more environmentally realistic concentrations and durations of exposure, and to assess chemical depuration. The 96-h median lethal concentration was 124 mg L(-1) , and the predicted 35-d no-observed-adverse-effect concentration was 0.7 mg L(-1) . No overt effects were observed following environmentally relevant exposures. Imidacloprid half-life in plasma was greater than 32 h. Measured concentrations of imidacloprid in porewater were significantly lower than the derived acute and chronic effect concentrations for white sturgeon. Exposure risk quotients were calculated using the effect concentrations and estimated environmental exposure. The resulting values were considerably below the level of concern for direct effects from either acute or chronic exposure to an endangered species.

Assessing the risk to green sturgeon from application of imidacloprid to control burrowing shrimp in Willapa Bay, Washington-Part I: exposure characterization.

Willapa Bay and Grays Harbor (WA, USA) comprise the largest region of commercial oyster cultivation on the Pacific Coast. The activities of 2 species of burrowing shrimp impair growth and survival of oysters reared on the intertidal mudflats. To maintain viable harvests, the oyster growers have proposed controlling the shrimp by applying the insecticide imidacloprid onto harvested beds. Green sturgeon (listed in the Endangered Species Act) forage on burrowing shrimp and could be exposed to imidacloprid in the sediment porewater and through consumed prey. Studies were conducted to evaluate the likelihood that green sturgeon would be exposed to imidacloprid and to characterize the subsequent environmental exposure. Comparisons between treated and untreated control beds following test application of the insecticide suggested that green sturgeon fed opportunistically on imidacloprid-impaired shrimp. The highest interpolated imidacloprid residue concentrations in field samples following chemical application were 27.8 µg kg(-1) and 31.4 µg kg(-1) in porewater and shrimp, respectively. Results from modeled branchial and dietary uptake, based on conservative assumptions, indicated that the porewater exposure route had the greatest contribution to systemic absorption of imidacloprid. The highest average daily uptake from porewater (177.9 µg kg(-1) body wt) was 9.5-fold greater than total dietary uptake (18.8 µg kg(-1) body wt). Concentrations and durations of exposure would be lower than the levels expected to elicit direct acute or chronic toxic effects.

Hydroids (Cnidaria: Hydrozoa) from Japanese tsunami marine debris washing ashore in the northwestern United States

Fourteen species of hydroids, including two anthoathecates and 12 leptothecates, are reported from the west coast of North America on debris from the tsunami that struck Japan on 11 March 2011. Six species were found on a dock that stranded at Agate Beach, Newport, Oregon, five from a boat at Gleneden Beach, Oregon, four from a dock in Olympic National Park, Washington, and two from a boat in Grays Harbor, Washington. Obelia griffini Calkins, 1899, the most frequently encountered species, was collected on three of the four derelict substrates. Eight of the species are known to be amphi-Pacific in distribution. Of the rest, at least five (S tylactaria sp.; Eutima japonica Uchida, 1925; Orthopyxis platycarpa Bale, 1914; Sertularella sp.; Plumularia sp.) are not previously known from the west coast of North America. Hydroids of E. japonica occurred as commensals in the mantle cavity of the mussel Mytilus galloprovincialis Lamarck, 1819. Obelia griffini, O. gracilis Calkins, 1899 (not its secondary homonym Laomedea gracilis Dana, 1846) and O. surcularis Calkins, 1899 are taken to be conspecific. Of the three simultaneous synonyms, precedence is assigned to the name O. griffini under the Principle of the First Reviser in zoological nomenclature. The species is sometimes regarded as identical with O. dichotoma (Linnaeus, 1758).

Tsunami impact to Washington and northern Oregon from segment ruptures on the southern Cascadia subduction zone

This paper explores the size and arrival of tsunamis in Oregon and Washington from the most likely partial ruptures of the Cascadia subduction zone (CSZ) in order to determine (1) how quickly tsunami height declines away from sources, (2) evacuation time before significant inundation, and (3) extent of felt shaking that would trigger evacuation. According to interpretations of offshore turbidite deposits, the most frequent partial ruptures are of the southern CSZ. Combined recurrence of ruptures extending ~490 km from Cape Mendocino, California, to Waldport, Oregon (segment C) and ~320 km from Cape Mendocino to Cape Blanco, Oregon (segment D), is ~530 years. This recurrence is similar to frequency of full-margin ruptures on the CSZ inferred from paleoseismic data and to frequency of the largest distant tsunami sources threatening Washington and Oregon, ~M w 9.2 earthquakes from the Gulf of Alaska. Simulated segment C and D ruptures produce relatively low-amplitude tsunamis north of source areas, even for extreme (20 m) peak slip on segment C. More than ~70 km north of segments C and D, the first tsunami arrival at the 10-m water depth has an amplitude of <1.9 m. The largest waves are trapped edge waves with amplitude ≤4.2 m that arrive ≥2 h after the earthquake. MM V–VI shaking could trigger evacuation of educated populaces as far north as Newport, Oregon for segment D events and Grays Harbor, Washington for segment C events. The NOAA and local warning systems will be the only warning at greater distances from sources.

Community variations in population exposure to near-field tsunami hazards as a function of pedestrian travel time to safety

Efforts to characterize population exposure to near-field tsunami threats typically focus on quantifying the number and type of people in tsunami-hazard zones. To develop and prioritize effective risk-reduction strategies, emergency managers also need information on the potential for successful evacuations and how this evacuation potential varies among communities. To improve efforts to properly characterize and differentiate near-field tsunami threats among multiple communities, we assess community variations in population exposure to tsunamis as a function of pedestrian travel time to safety. We focus our efforts on the multiple coastal communities in Grays Harbor and Pacific Counties (State of Washington, USA), where a substantial resident and visitor population is threatened by near-field tsunamis related to a potential Cascadia subduction zone earthquake. Anisotropic, path distance modeling is conducted to estimate travel times to safety, and results are merged with various population data, including residents, employees, public venues, and dependent-care facilities. Results suggest that there is substantial variability among communities in the number of people that may have insufficient time to evacuate. Successful evacuations may be possible in some communities assuming slow walking speeds, are plausible in others if travel speeds are increased, and are unlikely in another set of communities given the large distances and short time horizon. Emergency managers can use these results to prioritize the location and determine the most appropriate type of tsunami risk-reduction strategies, such as education and training in areas where evacuations are plausible and vertical-evacuation structures in areas where they are not.

Numerical model of wave-current interaction based on unstructured quadtree grid for nearshore coastal waters

According to the characteristics of complex topography, hydrology, sediment transport in coastal waters, the aim of this paper is to develop an implicit, depth-averaged 2-D numerical mode of coupling current and wave for coastal area. The hydrodynamic model is the two dimensional depth averaged non-linear shallow water equations with an unstructured non-staggered and multiple-level quadtree rectangular mesh with local refinement for important region. In this non-staggered system, primary variables u -, v -velocity, and water level are stored on the same set of grid points in order to simplify the program code, and fluxes at cell faces are determined using the Rhie and Chow’s momentum interpolation method to avoid spurious checkerboard oscillations. The discretized algebraic equations are solved iteratively using the GMRES method with ILUT preconditioning for speeding the computation. The Wave model is a two-dimensional spectral wave action model of taking into account the effect of wave breaking, shoaling, refraction, diffraction, wave-current interaction, bottom friction. The wave model readily provides the radiation stresses for the hydrodynamic model. The coupling model has been tested against measurement data for steady flow around a spur-dyke in a laboratory flume and tidal flows in Gironde Estuary, France and Grays Harbor, USA. The model reasonably well reproduces the temporal and spatial variations of water level, current speed and wave height observed in the measurements. It shows that the coupling current and wave model can simulate accurately the questions of tide and wave for complex domain, the modeling approach presented herein should be useful in engineering application and environmental protection for coastal area.

Development of a new method for the determination of residues of the neonicotinoid insecticide imidacloprid in juvenile chinook (Oncorhynchus tshawytscha) using ELISA detection

The neonicotinoid insecticide imidacloprid (IMI) has been proposed as an alternative to carbaryl for controlling indigenous burrowing shrimp on commercial oyster beds in Willapa Bay and Grays Harbor, Washington. A focus of concern over the use of this insecticide in an aquatic environment is the potential for adverse effects from exposure to non-target species residing in the Bay, such as juvenile Chinook (Oncorhynchus tshawytscha) and cutthroat trout (O. clarki). Federal registration and State permiting approval for the use of IMI will require confirmation that the compound does not adversely impact these salmonids following field applications. This will necessitate an environmental monitoring program for evaluating exposure in salmonids following the treatment of beds. Quantification of IMI residues in tissue can be used for determining salmonid exposure to the insecticide. Refinement of an existing protocol using liquid-chromatography mass spectrometry (LC-MS) detection would provide the low limits of quantification, given the relatively small tissue sample sizes, necessary for determining exposure in individual fish. Such an approach would not be viable for the environmental monitoring effort in Willapa Bay and Grays Harbor due to the high costs associated with running multiple analyses, however. A new sample preparation protocol was developed for use with a commercially available enzyme-linked immunosorbent assay (ELISA) for the quantification of IMI, thereby providing a low-cost alternative to LC-MS for environmental monitoring in Willapa Bay and Grays Harbor. Extraction of the analyte from the salmonid brain tissue was achieved by Dounce homogenization in 4.0 mL of 20.0 mM Triton X-100, followed by a 6 h incubation at 50-55 °C. Centrifugal ultrafiltration and reversed phase solid phase extraction were used for sample cleanup. The limit of quantification for an average 77.0 mg whole brain sample was calculated at 18.2 μg kg(-1) (ppb) with an average recovery of 79%. This relatively low limit of quantification allows for the analysis of individual fish. Using controlled laboratory studies, a curvelinear relationship was found between the measured IMI residue concentrations in brain tissue and exposure concentrations in seawater. Additonally, a range of IMI brain residue concentrations was associated with an overt effect; illustrating the utility of the IMI tissue residue quantification approach for linking exposure with defined effects.