Over time, caverns and fissures may form as limestone bedrock is dissolved. If the cavern collapses, sinkholes may form at the surface. Numerous sinkholes in a particular area form what is called karst topography. Florida has karst topography, which is more evident in some places of the state than others. In this assignment, you will describe and depict sinkhole formation and learn something about sinkholes in the Orlando area.
1. What is a sinkhole?
2. Describe how a sinkhole forms? Please discuss in your response the role of the water table with respect to the formation of sinkholes.
3. Draw a sinkhole in as much detail as possible.
At least 140 new sinkholes formed in the Orlando area (Orange and Seminole Counties) between 1961 and 1986, with an average of 11 new sinkholes appearing each year (Wilson and Beck 1992). Data from Wilson and Beck (1992) show that the appearance of new sinkholes is not equally distributed throughout the year (see Figure 1a). Also shown below is a graph of the average monthly rainfall for the Orlando area. Also show is a graph of the average monthly rainfall from that same area (Figure 1b).
Figure 1(a) Number of new sinkholes in Orange and Seminole Counties, Florida by month of the year for the years 1961 through 1986. From Wilson and Beck (1992). (b) Average monthly rainfall for Orange County. From http://www.guide-to-disney.com/when-to-go-to-disney-world/rainfall.php
4. After reviewing the graphs above, what months of the year are sinkholes most likely to form in the Orlando area? Which months of the year are least likely to experience the formation of a sinkhole?
5. What does the frequency of sinkhole formation seem to have with average monthly precipitation? Please write a hypothesis to explain this relationship.
6. Is Palm Beach Country more or less susceptible to sinkholes than the Orlando area? Explain why or why not. Note: you may need to investigate this online. List at least one internet resource you used to answer this question.
