ANNALS OF GEOPHYSICS, VOL. 45, N. 3/4, June/August 2002 563 Ground magnetometric surveys and integrated geophysical methods for solid buried waste detection: a case study Marco Marchetti, Lili Cafarella, Domenico Di Mauro and Achille Zirizzotti Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italy Abstract The detection of illegal buried waste by means of geophysical techniques has recently become a major effort in shallow geophysical investigations. In particular, detection and location of underground metallic storage tanks can be accomplished using different instruments and techniques. In this paper we describe the results of an investigation carried out in a tuff quarry in Riano Flaminio (north Rome, Italy). A preliminary magnetometric survey revealed the existence of anomalous zones in the analysed region. Excavation in some of the selected areas confirmed that the anomalies were generated by underground magnetic material: over 160 steel drums were found. After their removal, a new magnetometric survey was performed. On the basis of the new map, a multifrequency induction survey, a geoelectrical profile and GPR measurements were taken to extend the characterization of the subsoil. 1. Introduction The ever-increasing interest in environmental problems has recently spurred the scientific community to improve geophysical methods aimed at the detection of illegal waste disposal sites. In particular, detection and location of buried steel storage tanks can be done through several geophysical methods (Pierce and De Reamer, 1993; Foley, 1994; Vogelsang, 1995; Gibson et al., 1996; Marchetti et al., 1998). Generally in these cases the magnetic surveys are those most frequently used allowing a quick detection of underground metallic refuse. Typically, such method consists of two different kind of measurements: the total intensity of the local magnetic field and its vertical gradient. Moreover, detection of metallic buried waste using magnetometric surveys is advantageous for the low cost of its non invasive execution, and the rapidity of data collection and progressing. The exploration and localization of hazardous, toxic buried waste with only magnetic signature, depends on the depth of the target and on the material the hidden body is made of, since a non- magnetic body is completely transparent to detection by this kind of investigation. This limitation can be removed if other techniques such as active electromagnetic, GPR (Ground Penetrating Radar) and geoelectrical methods, based on different physical properties of the inspected matter, are used. This paper describes different investigation techniques used in an old tuff quarry at Riano Flaminio (north of Rome) where the presence of Mailing address: Dr. Marco Marchetti, Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Roma, Italy; e-mail: marchettim@ingv.it Key words environmental pollution geophysical surveys buried waste magnetic anomalies