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2006 ITGUAM2006 ITGUAM
High Resolution Seismic Reflection High Resolution Seismic Reflection Investigations for Salt Dissolution Investigations for Salt Dissolution
Features in KansasFeatures in KansasBy By
Bob HenthorneBob Henthorne
What is Salt Dissolution?What is Salt Dissolution?
Removing the natural occurring salt layers Removing the natural occurring salt layers by the addition of fresh water.by the addition of fresh water.
Salt Dissolution Features in KansasSalt Dissolution Features in Kansas
Dissolution FrontDissolution Front
Salt Mine ActivitiesSalt Mine Activities
Oil Production Oil Production
Investigative Procedures Using High-Resolution Seismic Reflection Techniques
Investigative Procedures Using HighInvestigative Procedures Using High--Resolution Seismic Reflection TechniquesResolution Seismic Reflection Techniques
GoalGoal: delineate subsurface expressions of : delineate subsurface expressions of sinkholes or paleosinkholes or paleo--sinkholessinkholes
lateral extentlateral extentlocate and estimate size of void areaslocate and estimate size of void areasidentify bridging or slumpidentify bridging or slumppreferential growth directionspreferential growth directionsevidence for catastrophic failure evidence for catastrophic failure
Acquisition ParametersAcquisition Parameters
240-channel fixed spread2.5 m receiver station spacing
Two 40 Hz geophones5.0 m source station spacing
IVI Minivib25-250 HzThree 10 second sweeps
240-channel fixed spread2.5 m receiver station spacing
Two 40 Hz geophones5.0 m source station spacing
IVI Minivib25-250 HzThree 10 second sweeps
A 240-channel fixed spread allowed the recording unit to remain stationary while the source traversed
about 600 m of line.
A 240A 240A 240---channel fixed spread allowed the recording channel fixed spread allowed the recording channel fixed spread allowed the recording unit to remain stationary while the source traversed unit to remain stationary while the source traversed unit to remain stationary while the source traversed
about 600 m of line. about 600 m of line. about 600 m of line.
Receivers set in the base of the ditch with the source on the road shoulder
Receivers set in the base of the ditch with the Receivers set in the base of the ditch with the Receivers set in the base of the ditch with the source on the road shouldersource on the road shouldersource on the road shoulder
Approximately 10 Gigabytes of information is collected Approximately 10 Gigabytes of information is collected each day! Data is recorded unfiltered and unstacked.each day! Data is recorded unfiltered and unstacked.
High Resolution Seismic may have not been developed for High Resolution Seismic may have not been developed for finding sinkholes but the end result is the same.finding sinkholes but the end result is the same.
Kansas ProjectsKansas Projects
USUS--50 and Victory Road50 and Victory RoadUSUS--50 Hutchinson South Bypass50 Hutchinson South BypassUSUS--61 from Hutchinson to McPherson61 from Hutchinson to McPhersonII--70 Crawford and Witt Sinkholes70 Crawford and Witt SinkholesUSUS--54 Interchange Between Goddard and 54 Interchange Between Goddard and WichitaWichita
Looking Northwest from the Project Looking Northwest from the Project Site!Site!
II--70 Sinkholes70 Sinkholes
Salt Member is 270 feet thick and approx. 1300 feet below I-70
I-70 has dropped over 20 feet and continues to sink at over 4 inches per year.
I-70 Witt and Crawford Site
US-50 and K-61 Sites
Hutchinson Salt and Site Map and Victory Road Seismic LinesHutchinson Salt and Site Map Hutchinson Salt and Site Map
and Victory Road Seismic Linesand Victory Road Seismic Lines
Sinkhole on US 50 Near Hutchinson
Sinkhole on US 50 Near Hutchinson
Intersection US 50 and Victory Road1998 subsidence measured @ 30 cm below grade at centerline2001 subsidence measured @ 1 m below grade at centerline & 100 m in diameterAveraging about 20 cm/yrCentered a few 10s of meters to the NW
Two orthogonal, 1 km seismic profiles
Intersection US 50 and Victory Road1998 subsidence measured @ 30 cm below grade at centerline2001 subsidence measured @ 1 m below grade at centerline & 100 m in diameterAveraging about 20 cm/yrCentered a few 10s of meters to the NW
Two orthogonal, 1 km seismic profiles
Interpretation of West/East Profile
Interpretation of West/East Interpretation of West/East ProfileProfile
Several episodes of subsidenceSeveral episodes of subsidenceCharacterized by both normal and reverse type Characterized by both normal and reverse type faultsfaultsBridging and undercompacted (relative)Bridging and undercompacted (relative)
Interpreted North/South ProfileInterpreted North/South ProfileInterpreted North/South Profile
Constrained to small faultConstrained to small fault--defined defined areaareaAborted subsidence featureAborted subsidence featureDormant paleosinkholeDormant paleosinkhole
Subsidence will continue in this area for many years into the future, as it has for at least the last million years.
Growth to the west should be expected @ vertical rates of 10 to 20 cm/yr
Subsidence will continue in this area for many years into the future, as it has for at least the last million years.
Growth to the west should be expected @ vertical rates of 10 to 20 cm/yr
No compelling evidence to suggest risk of catastrophic subsidence
No compelling evidence to suggest risk of catastrophic subsidence
CONCLUSIONSCONCLUSIONS
USUS--50 South Hutchinson Bypass50 South Hutchinson Bypass
US 61 from Hutchinson to US 61 from Hutchinson to McPhersonMcPherson
26 miles of new 426 miles of new 4--lane highway across the lane highway across the solution front of the salt.solution front of the salt.
Approximate location of the Dissolution Front 8th Avenue Sinkhole Location
Approximate Location of the Dissolution Front
Any Questions?