The Geophysical Quality Control Process In Oe Investigations: It Is Not An Option!
Theodore H. Asch
Event name: 16th EEGS Symposium on the Application of Geophysics to Engineering and Environmental Problems
Session: Unexploded Ordnance
Publication date: 06 April 2003
Info: Extended abstract, PDF ( 1.17Mb )
Clearance of UXO from closed, transferred, and transferring bases is not just a matter of a single
geophysical scan and excavation of detected anomalies. An important component not stressed enough
and often overlooked is an integrated quality control program that ensures a smooth integration of
analog QC/QA with digital QC/QA. A good Quality Control (QC) process will move a project much
closer to federal and state regulator acceptance than when QC is performed in a lackadaisical manner.
Comprehensive, consistent, and documented communication is the key to a successful operation. The
quality control process must also consider management of acquired data. This does not include just
geophysical data but all the data generated during a project. Quality data management must be present
from field acquisition through processing through interpretation through QC through data entry into a
GIS platform. Field observation of analog and digital acquisition, reacquisition, and excavation
procedures must also be part of the QC process. A QC manager must ensure that the site was completely
surveyed, that there are no missing survey lines within a grid, that there are no data “gaps” along survey
lines, and that there is no "bowing" out of survey lines beyond agreed upon specifications. The data
density along survey traverses must be matched to specific OE. Instrument functionality checks,
accurate and precise anomaly locations, and survey line orientations are required components.
Unreasonable data spikes must be removed from the data, there must be no data incongruities across
boundaries of grids, and the typical lag and heading corrections applied to data must be monitored. UXO
excavation results must be confirmed. This includes examination of dig sheets pre- and post-excavation,
independent surveying, and seeding of actual, site-specific, inert OE. Use of simulants is to be avoided.
Finally, a comprehensive quality control process is not optional.