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dc.contributor.advisor Adams, Herbert G. en
dc.contributor.author Ward, Michael Denis en
dc.date.accessioned 2017-01-11T20:10:26Z en
dc.date.available 2017-01-11T20:10:26Z en
dc.date.copyright 1994 en
dc.date.issued 1994-12 en
dc.identifier.uri http://hdl.handle.net/10211.3/183500 en
dc.description Includes bibliographical references (leaves 78-82) en
dc.description California State University, Northridge. Department of Geological Sciences. en
dc.description.abstract A computer program called Flatten Surface has been written which uses a method of best fitting of finite elements to restore a folded and faulted gridded surface to its predeformational state. The program calculates the intersection of the surface with fault surfaces so that the finite elements can be fit across faults. The method treats the regular grid of a surface as a series of columns of quadrilateral finite elements. The columns of the grid should be generally perpendicular to the fold axis and generally parallel to the faults. For each element that intersects a fault surface, two of its corner points are reassigned to be the element's calculated intersection points with the fault. Through a series of 3- D rotations each element is flattened by rotating the triangular halves of each element to horizontal. Each element is fit to its two previously fit neighbors, one to the side and the other below/above. The corner of the element that is coincident with the meeting point of the two neighboring elements is fit directly to the vector mean of the meeting point. The element is then rotated about this point using a simple iterative 2-D rotation procedure that balances area of overlap/underlap or distance between two adjacent previously fit finite elements. After the entire surface has been fit, a vector mean of all coincident corner points can be used when repeating the fitting process. When an element or a surrounding element is faulted, great care is taken in the selection of the coincident points to be averaged to ensure that the points are truly coincident. The fitting process can be repeated as many times as the user determines is necessary to achieve a satisfactory fit. The user determines best fit with statistics on the area of overlap/underlap and an experienced judgment call on a visual estimation of the distribution of overlap/underlap. The vector mean of all coincident corner points is used to create the output grid of the surface. The program is written in the c language and runs under UNIX and the SunView windowing system. Accuracy of the program was tested for the restoration of six data sets: (1, 2) two 4 x 4 hand created perfect grids, one unfaulted and one faulted; (3) a 100 x 100 faulted sine curve; (4) a 119 x 153 grid of a contour map of an experimentally folded sheet of paper (Gratier and others (1991); (5, 6) two 76 x 115 grids of contoured horizons from an oil field with faults. Results for the 4 x 4 grids and the faulted sine curve were perfect after the first fitting iteration. For the folded sheet of paper the total area of overlap/underlap was 0.000062% of the total area of the surface, after 96 fittings. For the oil-field data convergence was achieved rapidly and the degree of fit was good; after 94 fittings the total area of overlap/underlap was 0.000963% of the total area. Although a successful restoration does not guarantee a correct final interpretation, it helps check for local anomalies or errors in construction of the surface. en
dc.description.statementofresponsibility by Michael Denis Ward en
dc.format application/pdf en
dc.format.extent xii, 380 pages en
dc.language.iso en en
dc.publisher California State University, Northridge en
dc.rights.uri http://scholarworks.csun.edu//handle/10211.2/286 en
dc.subject.other Dissertations, Academic -- CSUN -- Geology. en
dc.title Flatten_Surface : a computer program to restore a folded and faulted gridded surface en
dc.type Thesis en
dc.date.updated 2017-01-11T20:10:26Z en
dc.contributor.department Geological Sciences en
dc.description.degree M.S. en
dc.contributor.committeemember Clarke, Donald D. en
dc.contributor.committeemember Fischer, Peter en
dc.contributor.committeemember Simila, Gerry W. en
dc.contributor.committeeMember Clarke, Donald D. en
dc.contributor.committeeMember Fischer, Peter en
dc.contributor.committeeMember Simila, Gerry W. en
dc.rights.license By signing and submitting this license, you the author grant permission to California State University, Northridge Graduate Studies to submit your thesis or dissertation, and any additional associated files you provide, to CSUN Scholarworks, the institutional repository of the California State University, Northridge, on your behalf.You grant to CSUN Scholarworks the non-exclusive right to reproduce and/or distribute your submission worldwide in electronic or any medium for non-commercial, academic purposes. You agree that CSUN Scholarworks may, without changing the content, translate the submission to any medium or format, as well as keep more than one copy, for the purposes of security, backup and preservation. You represent that the submission is your original work, and that you have the right to grant the rights contained in this license. You also represent that your submission does not, to the best of your knowledge, infringe upon anyone's copyright. If the submission contains material for which you do not hold copyright, or for which the intended use is not permitted, or which does not reasonably fall under the guidelines of fair use, you represent that you have obtained the unrestricted permission of the copyright owner to grant CSUN Scholarworks the rights required by this license, and that such third-party owned material is clearly identified and acknowledged within the text or content of the submission. If the submission is based upon work that has been sponsored or supported by an agency or organization other than the California State University, Northridge, you represent that you have fulfilled any right of review or other obligations required by such contract or agreement. CSUN Scholarworks will clearly identify your name(s) as the author(s) or owner(s) of the submission, and will not make any alterations, other than those allowed by this license, to your submission. en


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