On May 7, 2008, a major sinkhole developed in Daisetta, Texas about 60 miles northeast of Houston. The sinkhole, which was formed by the collapse of a void above a salt dome, grew in a single day from a minor sump to a hole with a diameter reported in the media as being more than 650 feet and a depth of over 250 feet. The collapse consumed several vehicles, drilling equipment, and several oil tanks, and resulted in the destruction of several buildings. On May 19, 2008, personnel from the Cybermapping Laboratory in the Geosciences Department at the University of Texas at Dallas mobilized to conduct an integrated survey of the area. Using state-of the-art equipment, we were able to create an accurate 3D photorealistic model of the entire sinkhole.

On May 7, 2008, a major sinkhole developed in Daisetta, Texas about 60 miles northeast of Houston. The sinkhole, which was formed by the collapse of a void above a salt dome, grew in a single day from a minor sump to a hole with a diameter reported in the media as being more than 650 feet and a depth of over 250 feet. The collapse consumed several vehicles, drilling equipment, and several oil tanks, and resulted in the destruction of several buildings. On May 19, 2008, personnel from the Cybermapping Laboratory in the Geosciences Department at the University of Texas at Dallas mobilized to conduct an integrated survey of the area. Using state-of the-art equipment, we were able to create an accurate 3D photorealistic model of the entire sinkhole.

Several overlapping scans incorporating several million data points were completed around the sinkhole with the Riegl LPM 800 HA laser profiler and numerous digital photographs were taken from a variety of locations. The TOPCON IS provided control for integrating Light Detection and Ranging (LiDAR) scans and for registration of digital photographs to the LiDAR image. The RTK-GPS was used to establish global location control points. The integrated survey was completed in one day. The point cloud laser data were merged using Polyworks software and a triangulated mesh (TIN) was created. The positions of the photographs were fixed to the TIN using UTD software at an accuracy of one pixel. The result is an accurate 3D photorealistic (virtual) model of the entire sinkhole.

The sinkhole will be resurveyed in October 2008 and a new 3D photorealistic model developed to allow comparison with the physiographic feature measured in May. The two images of the sinkhole will be differenced using UTD software to develop a quantitative assessment of growth of the sinkhole over the intervening months. The differencing software takes into account the uncertainties associated with the original and rescanned conversion of point clouds to surfaces. Additional tests will be undertaken to assess the impact on accuracy of using different types of laser scanners. Monitoring of the Daisetta sinkhole provides the opportunity to develop protocols and workflows for near real-time measurement and quantitative assessment of change associated with geologic hazards.

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