ANALOG SEISMIC PROFILES TO THREE-DIMENSIONAL GIS MODEL: CONSTRAINING THE GEOMETRY OF SUBSURFACE PALEOCHANNELS BENEATH DELAWARE BAY AND THE MID-ATLANTIC INNER CONTINENTAL SHELF

We have developed a method of taking older analog seismic profiles and building a database of depths to significant reflection events that can be entered into GIS software to create models of subsurface features. Subsequent maps and three-dimensional (3-D) images of the subsurface can then be visualized allowing for more accurate analysis and interpretation. This methodology has been applied to the networks of paleochannels that are present in the subsurface beneath the lower portion of Delaware Bay and the bordering Mid-Atlantic inner continental shelf. The project uses older analog seismic profiles to model these paleochannels in ArcGIS™ and as a 3-D model in ArcScene™. Depths to reflection events associated with the paleochannels were determined and input into ArcGIS along with the corresponding navigation data. Using ArcGIS – Geostatistical Analyst modeling with kriging, surface models of the paleochannels were created. To constrain optimal parameters to be used in the subsurface modeling, seafloor depths were determined from the seismic profiles, input into the Geostatistical Analyst routines, and then correlated to existing NOAA DEM bathymetry. Simple kriging using anisotropy gave the best statistical and visual results. The models of the paleochannels were then entered into ArcScene to create 3-D views allowing the subsurface geology to be analyzed and interpreted. The modeling results provide better constraints on the geometry of the paleochannels and can be used to better understand the recent geologic evolution of the region in response to sea-level fluctuations.