Summary: Preliminary Characterization of a NAPL-Contaminated
Site using Borehole Geophysical Techniques
Jonathan B. Ajo-Franklin Stanford University, Stanford, CA.
Jil T. Geller Lawrence Berkeley National Laboratory, Berkeley, CA.
Ernest L. Majer Lawrence Berkeley National Laboratory, Berkeley, CA.
John E. Peterson Lawrence Berkeley National Laboratory, Berkeley, CA.
Kenneth H. Williams Lawrence Berkeley National Laboratory, Berkeley, CA.
Jerry M. Harris Stanford University, Stanford, CA.
We present preliminary results from an on-going geophysical investigation of the former DOE Pinel-
las site, a site with confirmed non-aqueous phase liquid (NAPL) contamination. Our eventual goal
is the effective use of integrated crosswell geophysical methods, specifically seismic and radar tomog-
raphy, to remotely detect zones of high NAPL saturation. In this paper we discuss our motivation
and early efforts at using a combination of seismic and radar information to understand site ge-
ology and possible contaminant signatures. We also present our current approach to consistent
acquisition, preprocessing, tomographic inversion, and interpretation of joint seismic/radar profiles.
Although direct geophysical evidence of NAPL pools has not yet been obtained, several regions of
anomalous seismic attenuation were detected. These attenuating regions could not be explained
by borehole effects or lithology and may be caused by regions of partial gas or NAPL saturation.
Possible gas sources include biogenic production from contaminated regions and side-effects from