High-resolution Seismic Imaging of Catastrophic Salt Dissolution Sinkhole in Central Kansas

High-resolution seismic reflection techniques successfully imaged structural features associated with a sinkhole that formed catastrophically as a result of dissolution of the Permian-age Hutchinson Salt in central Kansas. Symmetric steep sided chimney structure formed instantaneously, which over time has continued to gradually enlarge and elongate to the east, forming an open bowl. Orthogonal high-resolution seismic lines were acquired to map the upper thousand feet and resolve structural features controlling development and possibly appraise future threat this feature represents to surface activities and local groundwater. High frequency vibrator and high-resolution seismic methods were used to acquire data from a 204 channel fixed spread. Common mid-point stacked sections depict very distorted subsurface that has undergone multiple phases of loading, failure, and subsidence. Stress built-up in roof rock overlying the salt void until catastrophic failure occurred along reverse fault planes within the tensional dome. Strain associated with bridged layers outside that dome is occurring along normal faults, which appear to have minimal vertical connectivity between interpreted reflectors. Oil-field disposal practices provided original fluids and pathway that initiated the dissolution process. Currently shallower groundwater fuels the dissolution process with oil-field brines contributing little, if at all.