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Abstract

Geological Survey of Finland (GTK) has carried out low altitude airborne geophysical surveys in Finland since<br>1972. Today 80 % of the country has been measured. The following systems are in use: magnetic, gamma<br>radiation and vertical coplanar EM and VLF electromagnetic. Airborne geophysics is a fast method to map landfill<br>areas at regional scale.<br>A successful example in Finland is the airborne detection of leakage from Rovaniemi landfill, in Northern Finland.<br>A clear quadrature electromagnetic anomaly (AEM) associated with the landfill was found. The resistivity of<br>the anomaly source is less than 20 Qm, whereas the surrounding resistivity is 100-300 Qm. In order to explain<br>the AEM-anomaly sources ground geophysical studies were conducted. Combining geophysical results with<br>geochemical analyses from peat and ground water, the contaminant plume has been confirmed.<br>GTK done airborne measurements at &nmhsuo, the large municipal landfill of Helsinki region. The landfill<br>area has been mapped in national airborne mapping program (1984) before the operation started (1987). The<br>second survey was done using tighter flight line spacing. Magnetic anomalies indicated the metallic waste and<br>human constructions. The attenuation of the gamma radiation revealed wet areas of the landfill. Comparing the<br>old and new AEM results it was possible to detect accurately and reliably weak conductivity anomaly variations<br>around the landfill area but there are no evidence of significant leakages.

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/content/papers/10.3997/2214-4609-pdb.205.1996_105
1996-04-28
2021-12-09
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http://instance.metastore.ingenta.com/content/papers/10.3997/2214-4609-pdb.205.1996_105
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