| Hydrocarbon-induced alteration || Soil or sediment sampling for indirect microbial or geochemical indicators, [[Magnetics#Aeromagnetic_surveys|aeromagnetic]], electrical, or radiometric | | Hydrocarbon-induced alteration || Soil or sediment sampling for indirect microbial or geochemical indicators, [[Magnetics#Aeromagnetic_surveys|aeromagnetic]], electrical, or radiometric |