I found it's really useful to deploy geophysical survey tool like FDEM to identify shallow subsurface geological situations.

what is FDEM? (Frequency Domain Electromagnetic Methods)

Frequency Domain Electro Magnetic induction (FDEM) involves generating an electromagnetic field which induces current in the earth which in turn causes the subsurface to create a magnetic field. By measuring this magnetic field, subsurface properties and features can be deduced. This method measures the magnitude and phase of induced electromagnetic currents, which are related to the subsurface electrical conductivity. Electrical conductivity is a function of the soil and rock matrix, percentage of saturation, and the conductivity of the pore fluids. EM instruments provide two measurements simultaneously, the electrical conductivity data and the in-phase component, which responds to magnetic susceptibility and metal.

FDEM has distinct advantages over many other techniques. Because no contact with the ground is required, FDEM can cover a large area quickly and therefore economically. In certain cases, depths of up to 50 meters can be mapped.