Subsidence/Sinkholes – Vulnerability Assessment

Sinkhole in a back yard[3]

About 20% of our country is underlain by “karst terrain” and is susceptible to a sinkhole event. The most damage from sinkholes tends to occur in Florida, Texas, Alabama, Missouri, Kentucky, Tennessee, and Pennsylvania.[1]

While sinkhole collapses are frequent in karst areas, there are a variety of other circumstances that can lead to such events. Many sinkholes form from human activity. Collapses can occur above old mines, from leaky faucets, when sewers give way, or due to groundwater pumping and construction.[2]

Subsidence/Sinkhole Vulnerability Assessment Questions

To assess your vulnerability to the threat of Subsidence or a Sinkhole to your family and property, perform an assessment to determine if you have knowledge of, are prepared and/or have a plan by answering the following questions:

General All-Hazard Questions:

  • Have you determined the disaster risks in your locale and the hazards that accompany them?
  • Do you know the emergency warning signals and alert notifications used in your community?
  • Have you instructed family members how to shut off water, gas and electricity to your house?
  • Have you made the necessary property preparations to reduce the damage from the hazard?
  • Do you have a backup generator in case of a prolonged power failure?
  • Have you purchased insurance (property, health, life, and/or hazard type)?
  • Have you made the necessary financial arrangements in case of a sudden evacuation and power outage that shuts down local ATMs and banks?
  • have you organized important documents and records and stored them in a portable lock box or safe-deposit box?
  • Have you performed a home inventory video taping the contents stored them in a portable lock box or safe-deposit box?
  • Does your family have an established Emergency Communication Plan and evacuation plan in place and asked an out-of-state person to serve as the “family contact”?
  • Have you assembled a shelter-in-place Emergency Supplies Kit in case you have to shelter at home and you are without power?
  • Have you assembled a mobile Emergency Supplies Kit that can serve as a “grab and go” bag?
  • Are you or someone in your family trained in first aid and CPR?
  • Have you made they necessary preparations and arrangements for pets, seniors, and the disabled?
  • Have you familiarized yourself with the emergency plans of your family member’s employment building, school, day care center, or nursing home?

Hazard Specific Questions:

  • Have you checked for cracks in your exterior of your home, such as in the block or stucco; and in the interior areas along joints, windows, or doors?
  • Have floors become sloping and becoming uneven?
  • Have you checked well water to see if it muddy or cloudy?
  • Have you noticed the formation of small ponds, as rainfall accumulates in new areas?
  • Have you noticed slumping or falling trees or fence posts?
  • Have you noticed a circular pattern of ground cracks around the sinking area?

U.S. Sinkhole Prone Karst Regions Map

The following map indicates the U.S. karst regions prone to sinkhole formation:[4]


A more detailed color-coded map indicating the different U.S. regions prone to sinkhole formation:[5]


  1. USGS – The Science of Sinkholes:
  2. USGS – The Science of Sinkholes:
  3. Image Source: [Accessed June 4, 2013]
  4. Image Source: [Accessed June 4, 2013]
  5. Image Source – USGS PDF: [Accessed December 4, 2014]