scholarly journals Active faulting in the northern Juan de Fuca Strait: implications for Victoria, British Columbia

2015 ◽  
Author(s):  
J V Barrie ◽  
H G Greene
Keyword(s):  
British Columbia ◽  
Active Faulting ◽  
Juan De Fuca ◽  
Juan De Fuca Strait

Seiche Excitation in Port San Juan, British Columbia

1979 ◽  
Vol 36 (10) ◽  
pp. 1223-1227
Author(s):  
D. D. Lemon ◽  
P. H. LeBlond ◽  
T. R. Osborn
Keyword(s):  
British Columbia ◽  
Water Waves ◽  
Pressure Gauge ◽  
Low Frequency ◽  
San Juan ◽  
External Forcing ◽  
Edge Waves ◽  
Rectangular Basin ◽  
Juan De Fuca ◽  
Juan De Fuca Strait

Seiche motions observed in San Juan Harbour with a bottom-mounted pressure gauge have been Fourier-analyzed and interpreted in terms of a theoretical model of oscillations in a rectangular basin with an exponential depth profile. Two of the observed periods (at 14.6 and 38.5 min) are identified with resonances of the basin; two other significant low frequency peaks (at 21 and 55 min) do not coincide with resonant periods of the basin and must be due to strong external forcing. Higher frequency fluctuations (20–160 s) are attributed to swell and to its subharmonic interactions with edge waves. Key words: water waves, seiches, mathematical model, Juan de Fuca Strait, British Columbia

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.

First Record of Whitebait Smelt (Allosmerus elongatus) from Juan de Fuca Strait, British Columbia

1971 ◽  
Vol 28 (10) ◽  
pp. 1681-1681
Author(s):  
W. E. Barraclough ◽  
R. M. Wilson
Keyword(s):  
British Columbia ◽  
First Record ◽  
Juan De Fuca ◽  
First Time ◽  
Juan De Fuca Strait

The whitebait smelt Allosmerus elongatus (Ayres) is recorded from British Columbia for the first time on the basis of three specimens from Juan de Fuca Strait caught November 2, 1969.

Concentrations of Nutrients and Chlorophyll on a Cross-Channel Transect in Juan de Fuca Strait, British Columbia

1978 ◽  
Vol 35 (3) ◽  
pp. 305-314 ◽  
Author(s):  
A. G. Lewis
Keyword(s):  
British Columbia ◽  
Key Words ◽  
Oceanic Water ◽  
Inshore Water ◽  
Geostrophic Flow ◽  
Juan De Fuca ◽  
Southern Side ◽  
Northern Side ◽  
The Cross ◽  
Juan De Fuca Strait

Nutrient and chlorophyll values were measured hourly at one of four stations on a cross-channel transect, over a 25-h period during each of 5 mo. Nitrate values increased with depth, chlorophyll decreased, and phosphate remained essentially unchanged during most months. Chlorophyll and phosphate values did not show consistent cross-channel trends, while nitrate levels were frequently higher on the southern side of the Strait. The cross-channel nitrate pattern can be at least partially explained in terms of geostrophic flow; greater amounts of nitrate-rich oceanic water enter at depth on the southern side of the Strait, while nitrate poor inshore water exists near the surface on the northern side. Key words: nutrients, chlorophyll, Juan de Fuca Strait

Sediment characteristics and sea-level history of Royal Roads Anchorage, Victoria, British Columbia

1988 ◽  
Vol 25 (11) ◽  
pp. 1800-1810 ◽  
Author(s):  
R. H. Linden ◽  
P. J. Schurer
Keyword(s):  
British Columbia ◽  
High Resolution ◽  
Sea Level ◽  
Seismic Reflection ◽  
Sediment Characteristics ◽  
Sea Floor ◽  
Juan De Fuca ◽  
History Of ◽  
Nearshore Sediments ◽  
Juan De Fuca Strait

High-resolution and airgun seismic-reflection mapping of the approaches to Esquimalt Harbour, Juan de Fuca Strait, reveal that offshore, sea-floor sediments consist of a widespread glaciomarine unit recognizable to the entrance of the strait. The upper part of the unit has been dated at approximately 10 000 radiocarbon years BP. An early postglacial sea-level low of at least −50 m appears to have formed a widespread unconformity. Nearshore sediments above the unconformity consist of sands, muddy fine sands, and minor gravel that were deposited in a prograding marine environment. Sediments have been accumulating off Esquimalt Harbour at a rate of approximately 1.9 cm per 100 years.

Stygobromus quatsinensis, a new amphipod crustacean (Crangonyctidae) from caves on Vancouver Island, British Columbia, with remarks on zoogeographic relationships

1987 ◽  
Vol 65 (9) ◽  
pp. 2202-2209 ◽  
Author(s):  
John R. Holsinger ◽  
D. Patrick Shaw
Keyword(s):  
British Columbia ◽  
Vancouver Island ◽  
Western United States ◽  
Pleistocene Glaciation ◽  
Juan De Fuca ◽  
Alternative Hypotheses ◽  
Amphipod Crustacean ◽  
Coarse Sediments ◽  
Juan De Fuca Strait ◽  
A New Species

Stygobromus quatsinensis, a new species of subterranean, freshwater amphipod crustacean, is described from caves on Vancouver Island, British Columbia, Canada. This is the 3rd stygobiont amphipod recorded from Canada and the 11th member of the genus Stygobromus to be found in localities north of the southern limits of Pleistocene glaciation. Stygobromus quatsinensis is a member of the hubbsi group, an assemblage of closely similar stygobiont species previously recorded from the central and western United States south of British Columbia. Two alternative hypotheses are proposed to explain the presence of S. quatsinensis on a glaciated island separated from the mainland by marine straits. One theory suggests that it evolved from putative ancestors that were present on the island before development of the Juan de Fuca Strait in the Eocene. The other suggests that it gained access to the island from the mainland through interstitial routes in coarse sediments of the Quadra Sand which infilled parts of the Georgia Strait in the late Pleistocene. Both theories assume that this species has survived glaciation in subglacial groundwater refugia.

Summary of Coastal Geologic Evidence for past Great Earthquakes at the Cascadia Subduction Zone

1995 ◽  
Vol 11 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Brian F. Atwater ◽  
Alan R. Nelson ◽  
John J. Clague ◽  
Gary A. Carver ◽  
David K. Yamaguchi ◽  
...  
Keyword(s):  
British Columbia ◽  
North America ◽  
Subduction Zone ◽  
Forest Soils ◽  
Pacific Coast ◽  
Cascadia Subduction Zone ◽  
Level Change ◽  
The Past ◽  
The Pacific ◽  
Juan De Fuca

Earthquakes in the past few thousand years have left signs of land-level change, tsunamis, and shaking along the Pacific coast at the Cascadia subduction zone. Sudden lowering of land accounts for many of the buried marsh and forest soils at estuaries between southern British Columbia and northern California. Sand layers on some of these soils imply that tsunamis were triggered by some of the events that lowered the land. Liquefaction features show that inland shaking accompanied sudden coastal subsidence at the Washington-Oregon border about 300 years ago. The combined evidence for subsidence, tsunamis, and shaking shows that earthquakes of magnitude 8 or larger have occurred on the boundary between the overriding North America plate and the downgoing Juan de Fuca and Gorda plates. Intervals between the earthquakes are poorly known because of uncertainties about the number and ages of the earthquakes. Current estimates for individual intervals at specific coastal sites range from a few centuries to about one thousand years.

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