Love-type seam-waves in washout models of coal seams
Journal Article
·
· Geophys. Prospect.; (United States)
The propagation of Love seam-waves across washouts of coal seams was studied by calculating synthetic seismograms with a finite-difference method. Seam interruption, seam end and seam thinning models ere investigated. The horizontal offset, the dip of the discontinuities and the degree of erosion served as variable parameters. Maximum displacement amplitudes, relative spectral amplitudes and phase and group slowness curves were extracted from the synthetic seismograms. Both seam interruption and seam thinning reduce the maximum displacement amplitudes of the transmitted Love seam-waves. The degree of amplitude reduction depends on the horizontal offset and the degree of erosion. It is four times greater for a total seam interruption than for an equivalent seam thinning with a horizontal offset of four times the seam thickness. In a seam cut vertically, the impedance contrast between the coal and the washout filling determines the maximum displacement amplitudes of the reflected Love seam-waves. They diminish by a maximum factor of four in oblique interruption zone discontinuities with a dip of maximum 27/sup 0/, and by a maximum factor of ten in a seam thinning with a degree of erosion of at least 22%.
- Research Organization:
- Institut fur Geophysik, Ruhr Universitat Bochum, Postfach 102148, 4630 Bochum 1
- OSTI ID:
- 6903199
- Journal Information:
- Geophys. Prospect.; (United States), Journal Name: Geophys. Prospect.; (United States) Vol. 34:8; ISSN GPPRA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
01 COAL, LIGNITE, AND PEAT
011000* -- Coal
Lignite
& Peat-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580203 -- Geophysics-- Geophysical Survey Methods-- (1980-1989)
AMPLITUDES
COAL DEPOSITS
COAL MINES
COAL SEAMS
DIAGRAMS
DIMENSIONS
DISPERSION RELATIONS
EROSION
FINITE DIFFERENCE METHOD
FREQUENCY DEPENDENCE
GEOLOGIC DEPOSITS
GEOPHYSICAL SURVEYS
IMPEDANCE
ITERATIVE METHODS
LOVE WAVES
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
MINERAL RESOURCES
MINES
NUMERICAL SOLUTION
REFLECTION
RESOURCES
SEISMIC ARRAYS
SEISMIC DETECTORS
SEISMIC SURFACE WAVES
SEISMIC SURVEYS
SEISMIC WAVES
SEISMOGRAPHS
SURVEYS
THICKNESS
UNDERGROUND FACILITIES
WAVE PROPAGATION
011000* -- Coal
Lignite
& Peat-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580203 -- Geophysics-- Geophysical Survey Methods-- (1980-1989)
AMPLITUDES
COAL DEPOSITS
COAL MINES
COAL SEAMS
DIAGRAMS
DIMENSIONS
DISPERSION RELATIONS
EROSION
FINITE DIFFERENCE METHOD
FREQUENCY DEPENDENCE
GEOLOGIC DEPOSITS
GEOPHYSICAL SURVEYS
IMPEDANCE
ITERATIVE METHODS
LOVE WAVES
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
MINERAL RESOURCES
MINES
NUMERICAL SOLUTION
REFLECTION
RESOURCES
SEISMIC ARRAYS
SEISMIC DETECTORS
SEISMIC SURFACE WAVES
SEISMIC SURVEYS
SEISMIC WAVES
SEISMOGRAPHS
SURVEYS
THICKNESS
UNDERGROUND FACILITIES
WAVE PROPAGATION