DEEP SEISMIC REFRACTION INVESTIGATION IN THE CANADIAN ARCTIC ARCHIPELAGO

Geophysics ◽  
1965 ◽  
Vol 30 (1) ◽  
pp. 87-96 ◽  
Author(s):  
G. W. Sander ◽  
A. Overton
Keyword(s):  
Seismic Refraction ◽  
Canadian Arctic ◽  
The Arctic ◽  
Seismic Profiles ◽  
Seismic Surveys ◽  
Refraction Seismic ◽  
Sverdrup Basin ◽  
Basic Portion ◽  
The Government ◽  
Government Of Canada

During 1962 and 1963, the Dominion Observatory conducted refraction seismic surveys in the islands north of the Canadian mainland. These surveys are part of a project of the Government of Canada to explore the Polar Continental Shelf. The operation consisted of three stationary recording units and a shooting party which traversed the frozen sea in a tractor train. Three refraction‐seismic profiles form a continous section from the Canadian Shield through the Franklinian Geosyncline and the Sverdrup Basin to the Arctic Ocean. Post Devonian sediments in the Sverdrup Basin were found to be 10 km thick. The lower, basic portion of the crust is indicated by a velocity of 7.3 km/sec at a depth of 24 km and the base of the crust at 38 km.

Applications of geophysical techniques in permafrost regions

1977 ◽  
Vol 14 (1) ◽  
pp. 117-127 ◽  
Author(s):  
W. J. Scott ◽  
J. A. Hunter
Keyword(s):  
Seismic Velocity ◽  
Seismic Refraction ◽  
Beaufort Sea ◽  
Test Site ◽  
The Arctic ◽  
Seismic Profiles ◽  
Refraction Seismic ◽  
Lake Bottom ◽  
Ice Content ◽  
The Hill

This paper reports the results of some recent geophysical experiments carried out in the Arctic with a variety of methods. In the Beaufort Sea, seismic refraction profiles obtained with both source and receivers on the seabottom indicate the presence of discontinuous near-bottom high-velocity (4200 m/s) material interpreted to be presently aggrading permafrost. Spring-time resistivity soundings taken through the ice in Kugmallit Bay, Beaufort Sea, show the top of permafrost at about 50 m below the bottom. Even for 5-km spreads, the base of permafrost was not observed.Off the southeast coast of Melville Island, refraction seismic profiles shot on the seabottom and resistivity soundings made through summer ice yielded data which correlate with known sub-bottom geology, but which gave no clear indication of either presence or absence of permafrost.Seismic and resistivity measurements made at a number of control sites in the Arctic Islands yielded typical velocities of 3500 m/s and resistivities of 1 × 106 ohm-m for ice-saturated sands. Some correlation was observed between seismic velocity and moisture contents in the range from 10% to 40%.Seismic and resistivity results in IOL Lake at the Involuted Hill test site, Tuktoyaktuk Peninsula, suggest the absence of permafrost under some parts of the lake bottom. On the hill itself, seismic up-hole shooting and VLF resistivity profiling give interpretations of ice distribution which correlate well with drill control. Gamma-gamma logs taken in some of the drill holes correlate well with ice content logged during drilling.

scholarly journals Measurement report: The chemical composition of and temporal variability in aerosol particles at Tuktoyaktuk, Canada, during the Year of Polar Prediction Second Special Observing Period

2021 ◽  
Vol 21 (18) ◽  
pp. 14199-14213
Author(s):  
John MacInnis ◽  
Jai Prakash Chaubey ◽  
Crystal Weagle ◽  
David Atkinson ◽  
Rachel Ying-Wen Chang
Keyword(s):  
Air Quality ◽  
Chemical Composition ◽  
Aerosol Particles ◽  
Road Dust ◽  
Quality Standard ◽  
The Arctic ◽  
Similar Range ◽  
The Government ◽  
Government Of Canada ◽  
Mass Concentrations

Abstract. The chemical composition, sources, and concentrations of aerosol particles vary on a seasonal basis in the Arctic. While existing research has focused on understanding the occurrence of aerosol particles during the Arctic winter and spring, less is known of their occurrence during the Arctic summer. In this study, atmospheric aerosol particle chemical composition and concentration were determined during July–September 2018 at Tuktoyaktuk, NT, Canada (69.4∘ N, 133.0∘ W), to coincide with the Year of Polar Prediction's Second Special Observing Period in the Arctic. The chemical composition of fine (PM2.5) and coarse (PM10–2.5) aerosol filter samples suggests the ocean, mineral and/or road dust, and combustion were sources of the sampled aerosol particles. Mass concentrations of PM2 and PM10, estimated from optical particle counter measurements, remained within a similar range during the study. However, elevated mass concentrations coincided with a festival in the community of Tuktoyaktuk, suggesting local human activity was an important source of aerosol particles. Mass concentrations of PM2, which promote negative health effects in humans, were significantly lower at Tuktoyaktuk than the national air quality standard recommended by the government of Canada. These measurements provide an important baseline to compare with future measurements associated with the assessment of aerosol chemistry and air quality in the Arctic.

scholarly journals Transport Airships for Scheduled Supply and Emergency Response in the Arctic

2021 ◽  
Vol 13 (9) ◽  
pp. 5301
Author(s):  
Barry E. Prentice ◽  
Yui-Yip Lau ◽  
Adolf K. Y. Ng
Keyword(s):  
Emergency Response ◽  
Oil Spills ◽  
Cost Comparison ◽  
The Arctic ◽  
Valuable Insight ◽  
Remote Communities ◽  
Mining Operations ◽  
Increased Risk ◽  
The Government ◽  
Government Of Canada

As climate change progresses, the Arctic Ocean creates opportunities for new resource development and navigation routes. Such economic opportunities are attractive, but carry with them an increased risk of accidents and oil spills. Existing methods of emergency response face enormous challenges in the Arctic because of its lack of transportation infrastructure and support services. Cargo airships offer a practical solution. Many airship designs are proposed that can carry over 30 tons, travel long distances at 150 km per hour, and land close to the emergency site. However, it is difficult to justify the economics of having enough capacity waiting and available to be marshaled in response to infrequent events. One solution is to develop a synergy with a new civilian cargo airship industry that can serve the regular transport needs of remote communities and mining operations. Through contingency contracts with these civilian operations, the Government of Canada could stretch its budgets and have access to the latest airship models and trained crews at locations across the Arctic. This paper gives valuable insight into the development of cargo airships. Advances in technology that make cargo airships a practical option in the 21st century are reviewed, and five competing airship designs are discussed. A case study of an existing rare earth mine proposal is used to illustrate the cost comparison of roads versus airships that could provide contingency services.

scholarly journals Marine geophysical investigations offshore East Greenland

1983 ◽  
Vol 115 ◽  
pp. 93-100
Author(s):  
H.C Larsen
Keyword(s):  
Seismic Data ◽  
Seismic Refraction ◽  
Magnetic Data ◽  
Seismic Profiles ◽  
East Greenland ◽  
Gravity And Magnetic ◽  
Marine Gravity ◽  
Refraction Seismic ◽  
Regional Project ◽  
Gravity And Magnetic Data

During August and September 1982 a marine geophysical survey was conducted on the East Greenland Shelf. The survey was part of the ongoing regional project NAD (Larsen & Andersen, 1982; Andersen et al., 1981; Risum, 1980; Larsen & Thorning, 1980). In all 2794 km of 30-fold multi-channel seismic data and marine gravity and magnetic data were acquired (fig. 33). The object of the NAD programme is to acquire regional coverage of aeromagnetic, multichannel seismic refiection, seismic refraction (sonobuoy), marine gravity and magnetic data of the East Greenland Shelf between latitudes 60° N and 78°N. Aeromagnetic data comprising 63000 line kilometres were acquired in 1979 (Larsen & Thorning, 1980) and 5000 km of marine geophysical data were acquired in 1980 and 1981 (Larsen & Andersen, 1982; Andersen et al., 1981). This year the final data for the project were collected. Thus, a total of 7800 km of multi-channel refiection seismic data and 50 sonobuoy refraction seismic profiles of 20 to 70 km length have been acquired (fig. 33). In addition, marine gravity and magnetics were run at most lines.

scholarly journals Measurement report: The chemical composition and temporal variability of aerosol particles at Tuktoyaktuk, Canada during the Year of Polar Prediction Special Observing Period

2021 ◽  
Author(s):  
John MacInnis ◽  
Jai Prakash Chaubey ◽  
Crystal Weagle ◽  
David Atkinson ◽  
Rachel Ying-Wen Chang
Keyword(s):  
Air Quality ◽  
Chemical Composition ◽  
Aerosol Particles ◽  
Road Dust ◽  
Quality Standard ◽  
The Arctic ◽  
Similar Range ◽  
The Government ◽  
Government Of Canada ◽  
Mass Concentrations

Abstract. The chemical composition, sources, and concentrations of aerosol particles vary on a seasonal basis in the Arctic. While existing research has focused on understanding the occurrence of aerosol particles during the Arctic winter and spring, less is known of their occurrence during the Arctic summer. In this study, atmospheric aerosol particle chemical composition and concentration were determined during July–September 2018 at Tuktoyaktuk, NT, Canada (69.4° N, 133.0° W) to coincide with the Year of Polar Prediction’s 2nd Special Observing Period in the Arctic. The chemical composition of fine (PM2.5) and coarse (PM10-2.5) aerosol filter samples suggests the ocean, mineral/road dust, and combustion were sources of the sampled aerosol particles. Mass concentrations of PM2 and PM10, estimated from optical particle counter measurements, remained within a similar range during the study. However, elevated mass concentrations coincided with a festival in the community of Tuktoyaktuk, suggesting local human activity was an important source of aerosol particles. Mass concentrations of PM2, which promote negative health effects in humans, were significantly lower at Tuktoyaktuk than the national air quality standard recommended by the Government of Canada. These measurements provide an important baseline to compare with future measurements associated with the assessment of aerosol chemistry and air quality in the Arctic.

scholarly journals Analysis of Near Surface Seismic Refraction for Geotechnical Parameters in Opolo, Yenagoa of Bayelsa State

2019 ◽  
pp. 1-12
Author(s):  
Francis Omonefe ◽  
Eteh Desmond ◽  
Oborie Ebiegberi ◽  
Oboshenure Kingsley Karo
Keyword(s):  
Seismic Velocity ◽  
Seismic Refraction ◽  
Constant Density ◽  
S Wave ◽  
Seismic Profiles ◽  
Near Surface ◽  
Underdeveloped Area ◽  
Refraction Seismic ◽  
Subsurface Soil ◽  
A Site

Three surface refraction seismic profiles were conducted in a site targeted for huge construction in an underdeveloped area in Opolo, Yenagoa city to portray some of the subsurface soil engineering characteristics for the purposes of construction. The Generalized Reciprocal Method (GRM) was used to interpret the acquired P and S-wave. Various shallow rock engineering parameters such as Oedometric modulus, Concentration Index, Material Index, Lame’s constant, Density Gradient, Stress Ratio, Shear modulus, Bearing capacity, and N-value were calculated in other to assess the strength of the subsurface  from a geophysical and engineering perspective. The values from the seismic velocity and strength parameters indicates that the bedrock layer (layer 3) of the area studied is characterized by more competent rock quality than layer 1 and 2. Hence, the Opolo site is suggested for construction activities with percussive measures.

scholarly journals A high-resolution ocean and sea-ice modelling system for the Arctic and North Atlantic Oceans

2015 ◽  
Vol 8 (1) ◽  
pp. 1-52 ◽  
Author(s):  
F. Dupont ◽  
S. Higginson ◽  
R. Bourdallé-Badie ◽  
Y. Lu ◽  
F. Roy ◽  
...  
Keyword(s):  
High Resolution ◽  
Sea Ice ◽  
North Atlantic ◽  
Thickness Distribution ◽  
The Arctic ◽  
Ice Thickness ◽  
The North ◽  
The Government ◽  
Government Of Canada ◽  
Environmental Prediction

Abstract. As part of the CONCEPTS (Canadian Operational Network of Coupled Environmental PredicTion Systems) initiative, The Government of Canada is developing a high resolution (1/12°) ice–ocean regional model covering the North Atlantic and the Arctic oceans. The objective is to provide Canada with short-term ice–ocean predictions and hazard warnings in ice infested regions. To evaluate the modelling component (as opposed to the analysis – or data-assimilation – component), a series of hindcasts for the period 2003–2009 is carried out, forced at the surface by the Canadian Global Re-Forecasts. These hindcasts test how the model represent upper ocean characteristics and ice cover. Each hindcast implements a new aspect of the modelling or the ice–ocean coupling. Notably, the coupling to the multi-category ice model CICE is tested. The hindcast solutions are then assessed using a validation package under development, including in-situ and satellite ice and ocean observations. The conclusions are: (1) the model reproduces reasonably well the time mean, variance and skewness of sea surface height. (2) The model biases in temperature and salinity show that while the mean properties follow expectations, the Pacific Water signature in the Beaufort Sea is weaker than observed. (3) However, the modelled freshwater content of the Arctic agrees well with observational estimates. (4) The distribution and volume of the sea ice is shown to be improved in the latest hindcast thanks to modifications to the drag coefficients and to some degree as well to the ice thickness distribution available in CICE. (5) On the other hand, the model overestimates the ice drift and ice thickness in the Beaufort Gyre.

scholarly journals Superficial structures cartography of the Essaouira basin under ground (Morocco), by small refraction seismic: contribution of the static corrections in the reinterpretation of the speeds variations.

2018 ◽  
Vol 149 ◽  
pp. 02080
Author(s):  
M. Dahaoui ◽  
L. AIT Brahim ◽  
A. El Adraoui ◽  
A. Abdelouafi ◽  
M. Dakki ◽  
...  
Keyword(s):  
Seismic Refraction ◽  
Seismic Profiles ◽  
Geological Interpretation ◽  
Weathered Zone ◽  
North East ◽  
Essaouira Basin ◽  
Refraction Seismic ◽  
North Eastern ◽  
Static Corrections ◽  
Altered Zone

The static corrections are a necessary step in the sequence of the seismic processing. This paper presents a study of these corrections in the Essaouira basin. The main objective of this study is to calculate the static corrections by exploiting the seismic data acquired in the field to improve the deep structures imaging. It is to determine the roof and the basis of the superficial layers which constitute the weathered zone while calculating the delays of seismic wave’s arrivals in these layers. The purpose is to cancel the effect of the topography and the weathered zone, in order to avoid any confusion when the seismic and geological interpretation. The results obtained show the average values of the static corrections varying between - 127 and 282 ms (double time), with existence of high values by location, particularly in the Eastern and North-Eastern of the basin, which meant the presence of altered zone with irregular topography and whose thickness and speeds vary laterally. In effect the variations of velocities in the fifty meters from the surface may introduce significant anomalies in seismic refraction, with heavy consequences when the interpretation or the drilling establishment. These variations are mainly due to lateral changes in facies and variations in the formations thickness. The calculation of the static corrections, revealed high values at certain areas (East and North-East), which will enable us to better orient the future campaigns in these zones. It is therefore necessary to concentrate the seismic cores drillings and the small refraction seismic profiles by tightening the seismic lines meshes in order to have the maximum values of static corrections and thereafter a better imaging of the reflectors.

Oil and Ice in the Beaufort Sea

Polar Record ◽  
1976 ◽  
Vol 18 (114) ◽  
pp. 237-250 ◽  
Author(s):  
Peter Wadhams
Keyword(s):  
Newfoundland And Labrador ◽  
Beaufort Sea ◽  
The Arctic ◽  
Oil Resources ◽  
Pack Ice ◽  
Sustained Operation ◽  
Fast Ice ◽  
Environmentally Sensitive ◽  
The Government ◽  
Government Of Canada

As the world's oil resources dwindle, the search for new supplies is touching regions of the globe previously considered too hostile for any kind of sustained operation. The ice-infested coastal waters of eastern and northern Canada are one such region. Already rigs have been at work off Newfoundland and Labrador where there is a long ice-free season and where drifting icebergs are the chief danger. Wells have been drilled on land in the Arctic islands and in one case from fast ice artificially thickened by flooding. However, a proposal to drill in the environmentally sensitive Beaufort Sea aroused widespread concern because of the enormous damage that could be caused by an accidental oil spill or by the blowout of an offshore well. People realized that the polar pack ice presents great dangers, that almost no information existed on the interactions between oil and sea ice, and that the oceanography and biology of the Beaufort Sea were understood only sketchily. To remedy these deficiencies a major environmental impact study, the Beaufort Sea Project, was undertaken in 1974–75 by the federal government of Canada and the oil industry acting in co-operation. The study also served the purpose of definng the conditions and restrictions under which the government would allow offshore drilling to proceed.

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