View All Items
(1 - 3 of 3)
- Title
- IDENTIFICATION OF SURFACE DEPRESSIONAL FEATURES POTENTIALLY RELATED TO SINKHOLES IN MARTIN COUNTY, FLORIDA, USING REMOTE SENSING TECHNIQUES.
- Creator
- Sanju, Khatri, Comas, Xavier, Florida Atlantic University, Department of Geosciences, Charles E. Schmidt College of Science
- Abstract/Description
-
Sinkholes are common karst features in Florida, having the highest rate of sinkhole occurrence in the US, which results in hundreds of millions estimated costs in damage per year and occasional life losses. While most sinkhole incidents reported in Florida relate to surface subsidence and collapse processes, other sinkhole formation mechanisms (like sagging) have received little attention as a relevant subsidence process. This is important since extensive areas of karst bedrock are overlain...
Show moreSinkholes are common karst features in Florida, having the highest rate of sinkhole occurrence in the US, which results in hundreds of millions estimated costs in damage per year and occasional life losses. While most sinkhole incidents reported in Florida relate to surface subsidence and collapse processes, other sinkhole formation mechanisms (like sagging) have received little attention as a relevant subsidence process. This is important since extensive areas of karst bedrock are overlain by variable thicknesses of non-soluble formations that may affect both the kinematics and damaging potential of these sinkholes in Florida. This research presents an automated GIS-based method to easily delineate surface depressional features in Martin County that result in surface depressional features and are related to cover sagging sinkholes. A total of 3,091 depressional features in Martin County were mapped using GIS methods and constrained with already existing direct drill cores. Results show a consistent statistically significant negative correlation between several morphometric features (i.e., area, perimeter, or depth) from these depressional features and depth to the limestone, suggesting that depressions are linked to sinkholes developed in deep-seated karst. While further subsurface imaging is needed to confirm this correlation, previous studies confirm these results and suggest that cover sagging, or cover suffusion sinkholes may represent a very large group of sinkholes traditionally unaccounted for in current sinkhole assessment maps in Florida. The methodology presented in this study can be easily extrapolated to other areas to further expand current sinkhole hazard and distribution maps.
Show less - Date Issued
- 2021
- PURL
- http://purl.flvc.org/fau/fd/FA00013872
- Subject Headings
- Sinkholes--Florida, Martin County (Fla.), Karst, Remote sensing
- Format
- Document (PDF)
- Title
- INVESTIGATING DEPRESSIONAL FEATURES ASSOCIATED WITH SINKHOLES IN DEEP-SEATED INTERSTRATAL KARST USING NEAR-SURFACE SEISMIC REFLECTION TECHNIQUES IN CENTRAL FLORIDA.
- Creator
- Khan, Haibat, Comas, Xavier, Florida Atlantic University, Department of Geosciences, Charles E. Schmidt College of Science
- Abstract/Description
-
Sinkholes are one of the major geohazards in karst areas, causing significant economic damage and even occasional loss of life. Sinkhole formation mechanisms vary depending on geological conditions but are initiated by dissolution of bedrock (generally carbonates or evaporites) below the ground resulting in ground surface deformation and eventual collapse. The process may be accelerated by natural events like storms or heavy rains and droughts, or human activities like water pumping or...
Show moreSinkholes are one of the major geohazards in karst areas, causing significant economic damage and even occasional loss of life. Sinkhole formation mechanisms vary depending on geological conditions but are initiated by dissolution of bedrock (generally carbonates or evaporites) below the ground resulting in ground surface deformation and eventual collapse. The process may be accelerated by natural events like storms or heavy rains and droughts, or human activities like water pumping or loading of the land surface. In Florida, limestone dissolution leading to sinkhole development often results in the formation of surface depressions that are often water-filled and develop into depressional wetlands. Previous studies using near-surface geophysical imaging techniques (including seismic refraction) in Central Florida have shown the correspondence between depressional wetlands and sinkholes originated in deep-seated interstratal karst with a variable overburden. However, these geophysical techniques are often unable to reach the karst interface which may typically be positioned at depths exceeding < 50-60 m. This research investigates the use of ground-based seismic reflection techniques to image deep paleokarst relief and better understand sinkhole development and extent below the overburden. This approach follows earlier studies by others using seismic reflection methods to identify sinkholes under lakes in Central Florida. While these previous studies deployed the method over water, the approach here investigates how land-based near-surface seismic reflection surveys may provide similar results below depressional wetlands. A total of three different locations with depressional wetlands under similar geological conditions (but somewhat variable depth to the karst interface) are investigated, including the Disney Wilderness Preserve near Poinciana (FL), the Allapattah Flats Wildlife Management Area near Palm City (FL); and the J.W. Corbett Wildlife Management Area in Palm Beach County (FL).
Show less - Date Issued
- 2022
- PURL
- http://purl.flvc.org/fau/fd/FA00013957
- Subject Headings
- Sinkholes--Florida, Karst, Imaging systems in geophysics, Seismic reflection method
- Format
- Document (PDF)
- Title
- Three-dimensional geomodeling to identify spatial relations between lithostratigraphy and porosity in the karst carbonate biscayne aquifer, southeastern Florida.
- Creator
- Westcott, Richard, Root, Tara L., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Geosciences
- Abstract/Description
-
In southeastern Florida, the majority of drinking water comes from the Biscayne aquifer. This aquifer is comprised of heterogeneous limestones, sandstones, sand, shell and clayey sand with zones of very high permeability. Visualizing the spatial variations in lithology, porosity and permeability of heterogeneous aquifers, like the Biscayne, can be difficult using traditional methods of investigation. Using the Roxar IRAP RMS software multi-layered 3D conceptual geomodels of the lithology,...
Show moreIn southeastern Florida, the majority of drinking water comes from the Biscayne aquifer. This aquifer is comprised of heterogeneous limestones, sandstones, sand, shell and clayey sand with zones of very high permeability. Visualizing the spatial variations in lithology, porosity and permeability of heterogeneous aquifers, like the Biscayne, can be difficult using traditional methods of investigation. Using the Roxar IRAP RMS software multi-layered 3D conceptual geomodels of the lithology, cyclostratigraphy and porosity were created in a portion of the Biscayne aquifer. The models were built using published data from borehole geophysical measurements, core samples, and thin sections. Spatial relations between lithology, cyclostratigraphy, porosity, and preferential flow zones were compared and contrasted to better understand how these geologic features were inter-related. The models show local areas of differing porosity within and cross-cutting different cycles and lithologies. Porosity in the Biscayne aquifer study area follows a hierarchy attributed to lithofacies with a pattern of increasing porosity for the high frequency cycles. This modeling improves understanding of the distribution and interconnectedness of preferential flow zones, and is thus an invaluable tool for future studies of groundwater flow and groundwater contamination in the Biscayne aquifer.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004337, http://purl.flvc.org/fau/fd/FA00004337
- Subject Headings
- Biscayne Aquifer (Fla.), Geophysics -- Florida -- Miami Dade County, Groundwater flow -- Florida -- Miami Dade County -- Mathematical models, Hydrology, Karst -- Florida -- Miami Dade County, Porosity, Sedimentary basins -- Florida -- Biscayne Aquifer, Sedimentology -- Statistical methods, Soil permeability
- Format
- Document (PDF)
