High resolution seismic mapping of a shallow aquifer
Date
1996-04
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ORCID
Type
Degree Level
Masters
Abstract
In the past, geological analysis did not often incorporate seismology into
integrated environmental studies. This was due in part to the expense of running multifold
reflection surveys, and additionally the lack of expertise of the individuals involved
in the environmental and groundwater fields. However, in recent history, the progress of
technology and increasing need for more detailed non-invasive investigations of
subsurface geology has encouraged the use of imaging methods such as CDP reflection
seismology.
The Dalmeny project was designed to address many of the issues related to the
differences between a standard petroleum seismology survey and a shallow survey in
glaciated areas. These differences exist in three principle areas: survey design and data
acquisition (CDP reflection profiling), data processing, and interpretation.
The post-Cretaceous geology of central Saskatchewan is composed of several till
and sand units (e.g. Dalmeny aquifer) and a non-glacial incised valley aquifer (Tyner
Valley aquifer). The sands of the Dalmeny and Tyner Valley are major aquifers and were
the principle targets for reflection surveying.
Utilisation of wave equation modelling in the survey design process provided
opportunities to optimise survey parameter values economically. Additionally, the use of
non-standard acquisition techniques provided enhanced data quality and increased
resolution over previous shallow seismic surveys.
Rigorous interpretation techniques have been used to extract as much information
as possible from the Dalmeny data set. Advanced interpretation techniques such as complex trace attribute analysis and velocity inversion were attempted. Results indicate
interesting variation and complexities which were not apparent on the standard section.
Near surface analysis of refraction information was used to quantify elastic properties
(velocities) for the highly weathered shallow(< 10m) strata.
The results of the Dalmeny project provided have shown that the acquisition of
high frequency (> 200 Hz) seismic data is possible in a glaciated terrain. The detailed
analytical procedure used in obtaining the acquisition parameters facilitated these results.
Enhanced data processing using advanced algorithms available for conventional
seismology significantly increased the frequency content and data quality.
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Degree
Master of Science (M.Sc.)
Department
Geological Sciences
Program
Geological Sciences