scholarly journals Tidal Resonance in Juan de Fuca Strait and the Strait of Georgia

2005 ◽  
Vol 35 (7) ◽  
pp. 1279-1286 ◽  
Author(s):  
Graig Sutherland ◽  
Chris Garrett ◽  
Mike Foreman
Keyword(s):  
Numerical Models ◽  
Puget Sound ◽  
Dissipative System ◽  
Tidal Elevation ◽  
Strait Of Georgia ◽  
The Pacific ◽  
Juan De Fuca ◽  
Resonant Period ◽  
Quality Factor Q ◽  
Juan De Fuca Strait

Abstract The resonant period and quality factor Q are determined for the semienclosed sea comprising Juan de Fuca Strait, Puget Sound, and the Strait of Georgia. The observed tidal elevation gain and phase change, from the Pacific Ocean to this inland sea, are fitted to the predictions of simple analytic models, which give a resonant period of 17–21 h and a Q of about 2. The low Q value, indicative of a highly dissipative system, is consistent with the need for numerical models for the area to employ large bottom friction coefficients. These include the effects of form drag.

Megalopal Spatial Distribution and Stock Separation in Dungeness Crab (Cancer magister)

1993 ◽  
Vol 50 (2) ◽  
pp. 416-429 ◽  
Author(s):  
G. S. Jamieson ◽  
A. Phillips
Keyword(s):  
Dungeness Crab ◽  
Cancer Magister ◽  
Strait Of Georgia ◽  
Daily Movement ◽  
The Pacific ◽  
Juan De Fuca ◽  
The Pacific Ocean ◽  
Estuarine Flow ◽  
Juan De Fuca Strait ◽  
Outer Coast

During the day, Dungeness crab (Cancer magister) megalopae from off the outer coasts of Vancouver Island and Washington are aggregated at about 25 m whereas those from the Strait of Georgia are at about 160 m. At night, both populations of megalopae seem to be mostly in the top metre of water. Juan de Fuca Strait, which connects the Strait of Georgia to the Pacific Ocean, typically has an estuarine circulation, with outflow in the top 50–100 m and deeper inflow. Because the daylight to dark ratio when megalopae are present is about 3:1, the Strait of Georgia and outer-coast megalopae are mostly retained within their own systems by currents at their daytime depths. Occasional intrusions of outer-coast megalopae into Juan de Fuca Strait may occur when estuarine flow in the Strait temporarily breaks down following sustained, strong, southwesterly winds; such intrusions are typically restricted to the south and head of Juan de Fuca Strait, and even extensive ones do not carry megalopae far into the Strait of Georgia. The daily movement of larval crab to cold (<10 °C), deep water in the Strait of Georgia may explain, at least partially, the delay in seasonal timing of settlement and their smaller physical size at settlement compared with outer-coast megalopae.

Surface Tidal Currents in Juan de Fuca Strait

1954 ◽  
Vol 11 (1) ◽  
pp. 14-31 ◽  
Author(s):  
R. H. Herlinveaux
Keyword(s):  
Pacific Ocean ◽  
Sea Level ◽  
Surface Current ◽  
Linear Functions ◽  
Strait Of Georgia ◽  
The Pacific ◽  
Juan De Fuca ◽  
The Pacific Ocean ◽  
The Difference ◽  
Juan De Fuca Strait

Surface-current measurements were made at half-hour intervals throughout thirty-hour periods at three positions in Juan de Fuca Strait. These were repeated during spring and neap ranges of the tide in spring, summer and late autumn during 1952. The currents are linear functions of the difference of sea level between the Pacific Ocean and the Strait of Georgia. A rule is given for predicting the currents from data in the Tide Tables.

Offshore Characteristics in the Deep Waters of the Strait of Georgia as Indicated by Bathypelagic Fish

1954 ◽  
Vol 11 (5) ◽  
pp. 501-506
Author(s):  
W. E. Barraclough ◽  
M. Waldichuk
Keyword(s):  
Deep Water ◽  
Fraser River ◽  
Strait Of Georgia ◽  
Deep Waters ◽  
Juan De Fuca ◽  
Bottom Waters ◽  
Chemical Conditions ◽  
Physical And Chemical ◽  
Juan De Fuca Strait ◽  
Inflowing Water

An attempt is made from oceanographical observations to explain the occurrence of certain bathypelagic species of fish which have been captured in the bottom waters of the southern Strait of Georgia. It is noted that there is a considerable seaward surface Sow of water from the Fraser River. The water from intermediate depths over the continental shelf forms the inflowing deep water of Juan de Fuca Strait mixing with the Fraser River water in the turbulent channels of the San Juan Archipelago. This mixture forms the deep inflowing water of southern Strait of Georgia and the outflowing surface water of the Juan de Fuca Strait as shown by salinity distribution and current measurements. The net inward movement of deep water is suggested as an agent of transport or a directive factor for the occurrence of these fish in this region. Physical and chemical conditions of the deep water in the Strait of Georgia are shown to be only slightly different from those found in the intermediate offshore water. It is probable that a combination of factors provides conditions suitable for survival of these species in the deep water of the southern Strait of Georgia.

Late Pleistocene history and geomorphology, southwestern Vancouver Island, British Columbia

1979 ◽  
Vol 16 (9) ◽  
pp. 1645-1657 ◽  
Author(s):  
Neville F. Alley ◽  
Steven C. Chatwin
Keyword(s):  
British Columbia ◽  
Continental Shelf ◽  
Late Pleistocene ◽  
Vancouver Island ◽  
Glacial Lakes ◽  
Small Lakes ◽  
Strait Of Georgia ◽  
Coast Mountains ◽  
Juan De Fuca ◽  
Juan De Fuca Strait

The major Pleistocene deposits and landforms on southwestern Vancouver Island are the result of the Late Wisconsin (Fraser) Glaciation. Cordilleran glaciers formed in the Vancouver Island Mountains and in the Coast Mountains had advanced down Strait of Georgia to southeastern Vancouver Island after 19 000 years BP. The ice split into the Puget and Juan de Fuca lobes, the latter damming small lakes along the southwestern coastal slope of the island. During the maximum of the glaciation (Vashon Stade), southern Vancouver Island lay completely under the cover of an ice-sheet which flowed in a south-southwesterly direction across Juan de Fuca Strait, eventually terminating on the edge of the continental shelf. Deglaciation was by downwasting during which ice thinned into major valleys and the strait. Most upland areas were free of ice down to an elevation of 400 m by before 13 000 years BP. A possible glacier standstill and (or) resurgence occurred along Juan de Fuca Strait and in some interior upland valleys before deglaciation was complete. Glacial lakes occupied major valleys during later stages of deglaciation.

Structural variation along the Devil's Mountain fault zone, northwestern Washington

2006 ◽  
Vol 43 (4) ◽  
pp. 433-446 ◽  
Author(s):  
Nathan Hayward ◽  
Mladen R Nedimović ◽  
Matthew Cleary ◽  
Andrew J Calvert
Keyword(s):  
Fault Zone ◽  
Structural Variation ◽  
Puget Sound ◽  
Seismic Reflection Data ◽  
Juan De Fuca Plate ◽  
The North ◽  
Reflection Data ◽  
Juan De Fuca ◽  
Main Fault ◽  
Juan De Fuca Strait

The eastern Juan de Fuca Strait is subject to long-term, north–south-oriented shortening. The observed deformation is interpreted to result from the northward motion of the Oregon block, which is being driven north by oblique subduction of the oceanic Juan de Fuca plate. Seismic data, acquired during the Seismic Hazards Investigation in Puget Sound survey are used, with coincident first-arrival tomographic velocities, to interpret structural variation along the Devil's Mountain fault zone in the eastern Juan de Fuca Strait. The Primary fault of the Devil's Mountain fault zone developed at the northern boundary of the Everett basin, during north–south-oriented Tertiary compression. Interpretation of seismic reflection data suggests that, based on their similar geometry including the large magnitude of pre-Tertiary basement offset, the Primary fault of the Devil's Mountain fault west of ~122.95°W and the Utsalady Point fault represent the main fault of the Tertiary Devil's Mountain fault zone. The Tertiary Primary fault west of ~122.95°W was probably kinematically linked to faults to the east (Utsalady Point, Devil's Mountain, and another to the south), by an oblique north–northeast-trending transfer zone or ramp. Left-lateral transpression controlled the Quaternary evolution of the Devil's Mountain fault zone. Quaternary Primary fault offsets are smaller to the east of ~122.95°W, suggesting that stress here was in part accommodated by the prevalent oblique compressional structures to the north. Holocene deformation has focussed on the Devil's Mountain, Utsalady Point, and Strawberry Point faults to the east of ~122.8° but has not affected the Utsalady Point fault to the west of ~122.8°W.

A Model Study of the Salish Sea Estuarine Circulation*

2011 ◽  
Vol 41 (6) ◽  
pp. 1125-1143 ◽  
Author(s):  
David A. Sutherland ◽  
Parker MacCready ◽  
Neil S. Banas ◽  
Lucy F. Smedstad
Keyword(s):  
Puget Sound ◽  
Exchange Flow ◽  
Salish Sea ◽  
Strait Of Georgia ◽  
Model Study ◽  
Juan De Fuca ◽  
Residence Time Distributions ◽  
The Difference ◽  
First Time ◽  
Volume Transports

Abstract A realistic hindcast simulation of the Salish Sea, which encompasses the estuarine systems of Puget Sound, the Strait of Juan de Fuca, and the Strait of Georgia, is described for the year 2006. The model shows moderate skill when compared against hydrographic, velocity, and sea surface height observations over tidal and subtidal time scales. Analysis of the velocity and salinity fields allows the structure and variability of the exchange flow to be estimated for the first time from the shelf into the farthest reaches of Puget Sound. This study utilizes the total exchange flow formalism that calculates volume transports and salt fluxes in an isohaline framework, which is then compared to previous estimates of exchange flow in the region. From this analysis, residence time distributions are estimated for Puget Sound and its major basins and are found to be markedly shorter than previous estimates. The difference arises from the ability of the model and the isohaline method for flux calculations to more accurately estimate the exchange flow. In addition, evidence is found to support the previously observed spring–neap modulation of stratification at the Admiralty Inlet sill. However, the exchange flow calculated increases at spring tides, exactly opposite to the conclusion reached from an Eulerian average of observations.

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