Skip to main content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Informational Only

This challenge is no longer accepting new submissions.

Detection of Underground Voids - Sinkholes

Voids / sinkholes underneath the ground’s surface are responsible for damage to many buildings and roads due to collapse. There is a need to detect underground voids / sinkholes as deep as 100 feet below the surface.

Department of Defense

Total Cash Prizes Offered: $15,000
Type of Challenge: Ideas
Submission Start: 01/28/2015 12:00 AM ET
Submission End: 02/27/2015 11:59 PM ET

This challenge is externally hosted.

You can view the challenge details here:


BACKGROUND Mining and Gas/oil exploration have led to great technology advances in detection of anomalies underground. Geologist can “see” pockets of materials through thousands of feet of rock. This usually works because there is a great contrast between the background (rock) and the target (oil). Also the “pocket” of target material is usually quite large as well. Even with all this technology, however, it is still difficult to consistently find a void or “hole” below ground.

Voids / sinkholes underneath the ground’s surface are responsible for damage to many buildings and roads due to collapse. There is a need to detect underground voids / sinkholes as deep as 100 feet below the surface. A lot of work has been done to predict conditions where sinkholes can form, but actual detection from above is quite difficult.

KNOWN TECHNOLOGIES There are many known technologies (some will be mentioned here) that work in some limited fashion but none that work consistently under all conditions. The Seeker is familiar with most known methods that exist today for this purpose. This Challenge is not about finding known technologies, but about finding new or repurposed technologies or adapting known technologies with new features to find voids below the surface.  The Seeker would like to discover any technologies that exist that have not been tried to detect these voids previously. Your knowledge and experience in other areas applied to this problem is what is requested.

Previous efforts using Ground Penetrating Radar (GPR), Gravity Gradiometer, Seismic and Acoustic sensors have produced limited capabilities due to geology/soil composition and the depth of some sinkholes. Some systems are effective in one geographical location and become useless in other locations. For example, it may work in wet but not dry soil, or in compact but not sandy soil. Many techniques can map a void when you already know something is there, but are not helpful in unknown areas.

THE CHALLENGE The Challenge is to come up with a system that can detect underground voids or sinkholes as deep as 30 feet below the surface (threshold) and preferably as deep as 100 feet below the surface (objective). The system must be able to detect voids in various types of geologies/soil compositions. Ideally it would provide a “picture” that shows the void and its location (GPS, Google Maps, or similar). The system should have as small a footprint as possible (deployable from a vehicle) and easily set up and utilized with minimal training by non-technicians (surveyors, realtors, law enforcement, border patrol, etc.), not only scientists/specialists.

Submissions to this Challenge should try to meet the following Technical Requirements:
  1. The system should be able to detect voids (empty space) as deep as 30 feet and preferably as deep as 100 feet.
  2. The system should be able to detect spherical voids that are 6 feet in diameter and preferably as small as 2 feet in diameter. Note: Voids may take on many other shapes.
  3. The system should be able to detect voids from a surface offset of at least 10 feet away and preferably up to 30 feet away.
  4. The system should provide a picture of the void and location in some form (GPS coordinates, Google Map, or similar).
  5. The system should be portable (by a vehicle) and have as small a foot-print as possible.
  6. Ideally the system could be operated and interpreted by a non-scientist/specialist.
  7. The system should work in all soil conditions (wet/dry, loose/compact, etc.), as well as in urban areas.
  8. Preference will be given to those techniques not used for this purpose before and those techniques that have been used for this purpose but have some significant changes made by the Solver.


This is an Ideation Challenge that requires only a written proposal to be submitted. At least one solution will be deemed the winner. The submission should include:
  1. Detailed description of a system, including its operating principle that can locate voids underground and meet the above requirements.
  2. Rationale for why the system can meet the above technical requirements.
  3. Include drawings if applicable.
  4. Include any method/process required for use.
Submitted proposals should not include any personal identifying information, information the Solvers do not want to make public or information the Solvers may consider as their Intellectual Property they do not want to share. This is an Ideation Challenge, which has the following unique features:
  • There is a guaranteed award.  The awards will be paid to the best submission(s) as solely determined by the Seeker. The total payout will be $15,000, with at least one award being no smaller than $7,500 and no award being smaller than $2,500.
  • The Solvers are not required to transfer exclusive intellectual property rights to the Seeker.  Rather, by submitting a proposal, the Solvers grants to the Seeker a royalty-free, perpetual, and non-exclusive license to use any information included in this proposal.
After the Challenge deadline, the Seeker will complete the review process and make a decision with regards to the Winning Solution(s). All Solvers that submitted a proposal will be notified on the status of their submissions; however, no detailed evaluation of individual submissions will be provided.