UNDERSTANDING THE CONSTRAINTS TO THE CORRECT APPLICATION OF THE UPWARD CONTINUATION FILTER IN GRAVITY DATA PROCESSING (Record no. 7103)
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| 000 -LEADER | |
|---|---|
| fixed length control field | 03205nam a22001457a 4500 |
| 008 - FIXED-LENGTH DATA ELEMENTS--GENERAL INFORMATION | |
| fixed length control field | 221207b ||||| |||| 00| 0 eng d |
| 100 ## - MAIN ENTRY--AUTHOR | |
| Author | NWOBODO Akachukwu Daniel |
| 245 ## - TITLE STATEMENT | |
| Title | UNDERSTANDING THE CONSTRAINTS TO THE CORRECT APPLICATION OF THE UPWARD CONTINUATION FILTER IN GRAVITY DATA PROCESSING |
| 250 ## - SUPERVISOR | |
| Supervisor | DR. O. B. BALOGUN |
| 260 ## - IMPRINT | |
| Place of publication | MOUNTAIN TOP UNIVERSITY |
| Department (College) | GEOSCIENCE |
| Date of publication | 2022 |
| 300 ## - COLLATION | |
| Pagination | xvii;'67 |
| 520 ## - SUMMARY, ETC. | |
| Summary, etc | Analytical simulation of the gravity response due to a square prism buried at known depths has been done and the resulting data have been upward continued to various heights in order to understand better the various constraints impeding the correct application of the upward continuation filter. The objectives of the study are to establish the relationship between the upward continuation distance and its equivalent output effect verifiable by other depth determination means, and to also investigate conditions for consistency in the determination of height of upward continuation in gravity field data processing by means of spectral analysis. 3D gravity response of a square prism with known thickness, dimensions and depth of burial was simulated using the expression for the gravity attraction due to a prism. Spectral analysis was then performed on the gravity response data to determine the depth of burial which was subsequently compared with the value of depth used in the simulation for agreement. After this<br/>process of depth of burial validation, upward continuation operation was performed on the simulated data to a known height such that the total depth to the buried body becomes the sum of depth of burial and the height of upward continuation. Spectral analysis was again performed on the upward continued data in order to compare again if the expected total depth to the buried body which is the sum of the depth of burial of the prism and the height of upward continuation agrees with the depth estimate obtained from spectral analysis. The height of upward continuation at which the depth determined from spectral analysis start to differ significantly was noted. The depth of the square prism was increased in a stepwise manner and the process was repeated. The height of upward continuation at which the depth determined from spectral analysis start to differ significantly was noted for all the various depths of burial as well. Results obtained showed that the computed depth from spectral analysis starts to differ significantly from expected depths at the total depth of 2500 m which is half of the size of the data grid size. When the total depth of 2500 m was exceeded, aliasing of the depth spectrum was observed. Result also showed that the relationship between the height to which gravity data is upward continued and the true output effect verifiable by spectral analysis method of depth evaluation is ratio 1:1.<br/>The study concluded that the upward continuation filter is highly reliable when the aliasing threshold has not been exceeded and that the extent of upward continuation done on a data can be verified by spectral analysis provided the depth of burial of a buried body/target is known. |
| 650 ## - TRACINGS | |
| Main Subject | GEOPHYSICS |
| 942 ## - ADDED ENTRY ELEMENTS (KOHA) | |
| Item type | Students Thesis |
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