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Evaluation of Volume Determinations for Modern Hypogene Karst Voids, San Salvador, Bahamas

Blauvelt, Kyle C.

Abstract Details

2012, Master of Science, University of Akron, Geology.

This study investigates the effect of data density on the calculation of cave passage volume for hypogene flank margin caves. Four cave passages on San Salvador, Bahamas, were surveyed using a high density, radial-surveying technique. The data sets were used to calculate cross-sectional areas of passages at multiple locations along a survey transects. Using the entire data set, total passage volumes were computed and then compared to reduced data sets to characterize the effect morphology had on area and volume determinations.

Three cave passages were measured using 17 survey stations per transect and one passage was measured with 33 survey stations. Adjacent stations divide the passage into slabs. Summing the volume of the slabs yields total passage volume. A total of 2,688 measurements were taken in the four passages. The measurements were used in a series of analyses to study the errors associated with employing depleted data sets of 4, 8, and 16-point radial data sets to calculate area and total passage volume. These errors were then correlated with certain morphological traits common throughout the passages. Longitudinal data points (entire survey stations) were also depleted to study the effect this had on calculating total volume.

The data reveals highly inaccurate area and slab volume values using depleted data sets and the sector method. Volume errors as high as 400 % were present using 4 and 8-point radial data sets. Not until data sets of at least 16-points were employed, did the range in error decrease to within 50 % difference. This indicates that hypogenic flank margin cave passages require high density data sets to accurately characterize their void space. This is in contrast to findings from epigene caves. Previous research in epigene caves suggest that the 4-point method and sector technique may be adequate for certain surveys. One similarity seen between epigene and hypogene data was the relative importance of radial data over longitudinal data. Both types of caves show larger errors in calculated volume when radial data points are depleted rather than depleting entire survey stations.

The experiment also examined shapes other than the sector method for modeling cross-sectional area. Using a rectangle, cross-sectional area and total passage volume are reduced to within 60 %. All three alternative models return errors less than 70 %. These shapes are more accurate than the sector technique in calculating cross-sectional area, and therefore, total passage volume.

Alternative shapes for modeling cross-sectional area allow the flexibility to selectively choose a model based on specific projects. The original sector technique should not be regarded as inadequate or inaccurate, but rather as not appropriate for every type of survey or project. These advances in modeling techniques improve our understanding of mega-porosity and subsurface void space.

Ira Sasowsky, Dr. (Advisor)
John Szabo, Dr. (Committee Member)
John Senko, Dr. (Committee Member)
123 p.

Recommended Citations

Citations

  • Blauvelt, K. C. (2012). Evaluation of Volume Determinations for Modern Hypogene Karst Voids, San Salvador, Bahamas [Master's thesis, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1329419705

    APA Style (7th edition)

  • Blauvelt, Kyle. Evaluation of Volume Determinations for Modern Hypogene Karst Voids, San Salvador, Bahamas. 2012. University of Akron, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1329419705.

    MLA Style (8th edition)

  • Blauvelt, Kyle. "Evaluation of Volume Determinations for Modern Hypogene Karst Voids, San Salvador, Bahamas." Master's thesis, University of Akron, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1329419705

    Chicago Manual of Style (17th edition)