January 13, 2004
D. M. Fitzgerald, G. A. Zarillo & S. Johnston
Fig. 6. Structure contour map of the depth to acoustic basement (in meters) that was produced
from a detailed shallow seismic survey of the area. The map identifes former entrance channels
occupied by the paleo-Kennebec River, Maine (from Buynevich et al., 1999).
sensor (GPS) and the sonar measurement, are recorded with on board instrumenta-
tion and incorporated into the post-processing procedure (USACE 2001). Care must
be taken to prevent/minimize other errors such as inaccurate alignment of sensors,
transducer draft depth, and sound velocity measurements (USACE 2001).