HR: 08:45h
AN: NS21A-02    [Abstracts]
TI: A High-Resolution Seismic Survey to Image the top of Salt at Avery Island, Louisiana
AU: Standridge, D
EM: dawniedoo2002@yahoo.com
AF: Energy Institute, University of Louisiana at Lafayette, 635 Cajundome Blvd., Lafayette, LA 70506 United States
AU: * Schneider, R V
EM: rschneider@louisiana.edu
AF: Energy Institute, University of Louisiana at Lafayette, 635 Cajundome Blvd., Lafayette, LA 70506 United States
AU: Bishop, C E
EM: bishopc@louisiana.edu
AF: Energy Institute, University of Louisiana at Lafayette, 635 Cajundome Blvd., Lafayette, LA 70506 United States
AU: Kinsland, G L
EM: glkinsland@louisiana.edu
AF: Energy Institute, University of Louisiana at Lafayette, 635 Cajundome Blvd., Lafayette, LA 70506 United States
AU: Serpa, L F
EM: LSerpa@uno.edu
AF: Department of Geology and Geophysics, University of New Orleans, 2000 Lakeshore Drive, New Orleans, LA 70148 United States
AB: We performed a shallow high-resolution 2-D seismic reflection study in an attempt to image the top of the salt dome at Avery Island, Louisiana. The survey was conducted using a 48-channel Geoder system with an Elastic Wave Generatorr (accelerated weight drop surface source) as the source. The purpose is to aid in mine planning by Cargill Salt and in shallow subsurface environmental planning by McIlhenny Co. The processing scheme included, 1) conversion to ProMaxr compatible format, 2) geometry establishment using both GPS and topographic map locations, 3) record truncation and resampling in time, 4) ground roll, air wave and refractor mute, 5) filter testing, design and application (dominant frequency is found to be about 100 Hz), 6) velocity analysis and 7) stacking. The line runs from near the mineshaft down the main road to near the water of the surrounding canal near the flank of the dome. The final stack of the data showed five reflectors at the end of the line nearest the flank of the dome, the most significant reflector having stacking velocities over 2,000 m/s. This indicates the possible presence of salt-cemented sediments similar to those found by studies on Weeks Island. No unambiguous "salt reflector" is identified. It is possible that although the salt is present, the salt-clastic sediment interface does not produce the expected strong reflector perhaps due to a gradational contact or, the salt is, in some areas, too near the surface causing the refraction to interfere with the reflection or the interface is too uneven to be imaged with our survey. Surveys and processing of other designs and/or well data might differentiate between these hypotheses.
DE: 1219 Local gravity anomalies and crustal structure
DE: 8015 Local crustal structure
SC: Near-Surface Geophysics [NS]
MN: 2005 Joint Assembly