A volume integral method is developped in order to study the scattering of a plane wave by a small particle placed below a metallic surface. The scattering patterns produced in the near field are analysed. For p-polarization, a plasmon is excited producing interferences along the surface. It is shown that this interference pattern might be used to measure the dielectric constant of the metal. The scattered field has a pronounced maxima for p-polarization if the particle is close to the interface. This effect is due to a resonant interaction between the surface and the dipole already identified in the context of SERS as an image enhancement effect. Finally, the resolution of a near field detection of a subsurface scatterer is discussed on the basis of the transverse extension of the scattered field.