This thesis involves the interpretation of gravity and other
potential field anomalies caused by layers of varying thickness. The
partial differential equations of potential field theory are reviewed for
gravitational and magnetic force fields. A similar review is carried
out for steady-state heat transport and diffusion processes. For the
gravitational force fields, solutions of the partial differential equations
are listed in integral form for the following cases: single body with given
constant density, infinitely thin sheet with variable mass density, two
homogeneous layers with a slowly undulating interface and two layers
with a vertically-constant-density lower layer. The solutions give the
gravity anomaly in terms of the parameters of the source body. Heat
transport phenomena of a similar nature are also discussed.
The general expression obtained for the two homogeneous layers
with a slowly undulating interface is used as an integral equation and
applied to the derivation of crustal thickness variation in Oregon on
the basis of two different computational methods. The first method,
called the digitized algebraic method, solves the quasi-linearized
form of the general integral equation by an iterative technique for three
reference va1ues of the mean depth of the crust-mantle interface, viz.,
25 km, 30 km, and 35 km. The second approach, called the second
derivative approximation method, gives a solution by the Fourier
transform technique to the linearized form of the general integral
equation for the same three reference values of the mean depth of the
crust-mantle interface.
The above results as to the depth of the crust-mantle interface
are compared with recent results with seismic refraction and dispersion data obtained along a profile in eastern Oregon. The value of
the reference depth d which best reconciles with the above results
and the seismic results turns out to be 30.25 km for the depth data on
the basis of the algebraic method and 28.90 km for the depth data
obtained with the second derivative approximation method. / Graduation date: 1972
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/29009 |
| Date | 29 April 1971 |
| Creators | Adotevi-Akue, George Modesto |
| Contributors | Bodvarsson, Gunnar |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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