HR: 0830h
 AN: NS41B-06 INVITED     [Abstracts]
 TI: Ground Truth for Geological and Geophysical Mapping of New York Harbor
 AU: * Murphy, W
EM: murphy@earthworks2020.com
 AF: Earthworks, LLC, P.O. Box 178, Newtown, CT 06470-0178 United States
AU: Ward, W B
 EM: ward@earthworks2020.com
 AF: Earthworks, LLC, P.O. Box 178, Newtown, CT 06470-0178 United States
AU: Boyd, B
EM: beckett@earthworks2020.com
 AF: Earthworks, LLC, P.O. Box 178, Newtown, CT 06470-0178 United States
AU: Fleming, G
EM: gfleming@earthworks2020.com
 AF: Earthworks, LLC, P.O. Box 178, Newtown, CT 06470-0178 United States
AU: Nolen-Hoeksema, R
EM: rcnh@earthworks2020.com
 AF: Earthworks, LLC, P.O. Box 178, Newtown, CT 06470-0178 United States
AU: Murphy, W
EM: willmurphy@earthworks2020.com
 AF: Earthworks, LLC, P.O. Box 178, Newtown, CT 06470-0178 United States
AB: As part of the project to deepen the harbors of the Ports of New York, Newark, and Elizabeth to 50 feet, we are mapping the geology of New York and New Jersey harbor, particularly the eastern edge of the Newark Basin, with geophysical measurements and core borings. The results are geological cross-sections, stratigraphic columns, and geological maps with resolutions approaching 1 foot. Sonar images map the surface of the bottom. Multichannel and single-channel, reflection seismic methods penetrate the sediment and rock to 100 feet below mean low water (MLW). The subsurface materials include black silt, gray silt, gray sands, Pleistocene till, Pleistocene varves, Jurassic diabase, Triassic sands and shales, Ordovician serpentinite, Cambro-Ordovician schist. We measure formation properties including lateral extent, thickness, strike and dip, contamination, fracture density, and diggability. The range of compressional velocity among these materials is a factor of six. Fundamental axioms of mapping, causality, equipresence, and frame indifference require sampling by core borings. Sampling is straightforward yet rarely required. We calibrate the water column for bathymetric studies and the subsurface for geotechnical studies. We measure

  • Blow counts (or drill rate)
  • Recovery efficiency
  • Lithological description
  • Digital photographs
  • Rock quality designation (RQD)
  • Fractures per foot
  • Ultrasonic compressional wave velocity
  • Unconfined compressive strength The measurements provide
  • Ground truth
  • Stratigraphic calibration
  • Velocity modeling for time-to-depth conversion
  • Material for correlation and experimentation The acoustic properties of the materials involved vary as a function of season. A sensitive issue is stability of the sediments in the channel slope. We place the hundreds of core borings into a single reference frame with the geophysical measurements. The geological maps and cross-sections follow from the interpretation of the processed geophysical results.
    DE: 0900 EXPLORATION GEOPHYSICS
     DE: 3000 MARINE GEOLOGY AND GEOPHYSICS
     DE: 5100 PHYSICAL PROPERTIES OF ROCKS
     SC: Near-Surface Geophysics [NS]
     MN: 2005 Joint Assembly