Three-dimensional seismic characterization of karst in the Floridan aquifer system, southeastern Miami-Dade County, Florida

Scientific Investigations Report 2018-5117
Prepared in cooperation with the Miami-Dade County Water and Sewer Department
By: , and 

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Abstract

Two three-dimensional seismic surveys totaling 3.4 square miles were acquired in southeastern Miami-Dade County during 2015 as part of an ongoing broad regional investigation by the U.S. Geological Survey, in cooperation with the Miami-Dade Water and Sewer Department, that includes mapping and karst characterization of the Floridan aquifer system in southeastern Florida. Twenty columniform seismic-sag structures were identified in the three-dimensional seismic data acquired at the South Miami Heights study area in Miami-Dade County, Florida. The seismic-sag structures are commonly composed of a lower and upper seismic facies, where the lower facies is interpreted to be a high permeability column-shaped volume of intense karstification composed of faults, fractures, and collapsed caves, and the upper facies is interpreted to be a lower permeability column-shaped volume composed of sagging suprastratal reflections having little or no faulting, fracturing, or caves. The seismic-sag structures are columniform karst-collapse structures that formed by cave collapse or stoping (upward void migration caused primarily by the mechanical process of ceiling collapse) or both in carbonate rocks of the early Eocene Oldsmar Formation and in some cases in the lowermost part of the middle Eocene Avon Park Formation. Columniform subsidence and sagging of overburden succeeded karst collapse in the lower part of the structures. At the study area, there may be relatively higher potential for the columniform karst-collapse structures to provide cross-formational fluid migration upward from the Boulder Zone into the lower part of middle confining unit 2 as compared to a lower potential for cross-formational fluid migration from the upper part of middle confining unit 2 upward to the Upper Floridan aquifer.

Suggested Citation

Cunningham, K.J., Dixon, J.F., Westcott, R.L., Norgard, S., and Walker, C., 2018, Three-dimensional seismic characterization of karst in the Floridan aquifer system, southeastern Miami-Dade County, Florida: U.S. Geological Survey Scientific Investigations Report 2018–5117, 39 p., https://doi.org/10.3133/sir20185117.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Methods
  • Preliminary Seismic Characterization of Karst
  • Summary and Conclusions
  • References

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Three-dimensional seismic characterization of karst in the Floridan aquifer system, southeastern Miami-Dade County, Florida
Series title Scientific Investigations Report
Series number 2018-5117
DOI 10.3133/sir20185117
Year Published 2018
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) FLWSC-Ft. Lauderdale
Description vii, 39 p.
Country United States
State Florida
County Miami-Dade County
Other Geospatial Floridan Aquifer System
Online Only (Y/N) Y