The Most Recent Cascadia Earthquake and Native American Narratives     

Solow  Andrew  Beet  Andrew  McManus  Shauna 《Mathematical Geosciences》2019,51(5):683-690

The Cascadia subduction zone fault lies just off the Pacific coast of the USA and Canada. Although this fault has been seismically inactive over the written history of the Cascadia region, it has the potential to produce catastrophic earthquakes and tsunamis. A variety of dating methods have been used to show that the most recent Cascadia earthquake occurred in 1700. Among these methods is an informal analysis of oral traditions handed down by Native American peoples that appear to refer to a major earthquake in this region. A central difficulty in analyzing these narratives quantitatively is their use of a generation and other qualitative measures of time that have no fixed lengths. Here, these narratives are analyzed under an explicit statistical model of the lengths of these measures. The results raise a question about the previous conclusion that these narratives all refer to the most recent Cascadia earthquake.

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Cooperation between bound waters and hydroxyls in controlling isotope-exchange rates     

Adele F. Panasci  J. Gregory McAlpin  C. André Ohlin  Shauna Christensen  James C. Fettinger  R. David Britt  James R. Rustad  William H. Casey 《Geochimica et cosmochimica acta》2012

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Influence of the Three Gorges Project on saltwater intrusion in the Yangtze River Estuary   总被引：3，自引：0，他引：3  

Qiang An  Yanqing Wu  Shauna Taylor  Bin Zhao 《Environmental Geology》2009,56(8):1679-1686

The Three Gorges Project (TGP) is a transcentury project that has aroused world attention. It is expected that the flow velocity and runoff of the Yangtze River will be changed after the project has been accomplished. Consequently, however, the ecological environment in the Yangtze River Basin, particularly in the estuary region, will be affected. Salinity intrusion into the Yangtze River estuary, in general, is mostly affected by the Yangtze River discharge and its external tidal level. This paper focuses on examining the influence of changes in runoff on salinity value. The question, to which should be paid attention is: how is the interaction between changes in runoff of the Yangtze River and salinity distribution in the Yangtze River estuary, China? In this research, a three-dimensional model has been used to identify the effects of runoff change on salinity distribution. The drawn conclusion is that the change of salinity is influenced by discharge variation. Positive and negative impacts of TGP would both turn up but in different period. In sum, TGP is in favor of restraining saltwater intrusion. Nevertheless a suitable method should be found to resolve its negative influences.  相似文献   

Evaluation of swimmer-based rip current escape strategies   总被引：2，自引：1，他引：1  

R. Jak McCarroll  Robert W. Brander  Jamie H. MacMahan  Ian L. Turner  Ad J. H. M. Reniers  Jenna A. Brown  Anthony Bradstreet  Shauna Sherker 《Natural Hazards》2014,71(3):1821-1846

Rip currents are the primary hazard on surf beaches, and early studies described them as fast, shore-normal flows that extended seaward of the surf zone. Based on this traditional view, commonly promoted safety advice was to escape a rip current by swimming parallel to the beach. However, recent studies have shown dominant rip current re-circulation within the surf zone and have endorsed floating as an appropriate escape strategy. Here, a first quantitative assessment of the efficacy of various rip current escape strategies, with a focus on the underlying physical processes, is presented. A field study was conducted at Shelly Beach, NSW, Australia, measuring three rip currents (two open beaches, one topographic) over 3 days in varying wave conditions. Floating was found to be a longer duration, more variable escape strategy ( $ \overline{t} $  = 3.8 min, σ = 2.4 min), than swimming parallel ( $ \overline{t} $  = 2.2 min, σ = 1.0 min). Neither of the scenarios is 100 % foolproof, and both fail in some scenarios, making simplified safety recommendations difficult. Swim parallel failures are related to swimming against the alongshore current of the rip circulation. Float failures related to surf zone exits, with the highest exit rate occurring in the topographic rip. Float failures also occurred due to multiple re-circulations without the person attaining safe footing on the bar. The variable spatial and temporal behaviour of rip currents suggests that a single escape strategy safety message is inappropriate. Instead, a combined approach and scenario-specific safety advice should be considered by beach safety practitioners to promote to the public.  相似文献   

Arctic communities perceive climate impacts on access as a critical challenge to availability of subsistence resources     

Todd J. Brinkman  Winslow D. Hansen  F. Stuart Chapin  Gary Kofinas  Shauna BurnSilver  T. Scott Rupp 《Climatic change》2016,136(3-4):413-425

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