Onshore electromagnetic reservoir monitoring

An onshore electromagnetic (EM) reservoir monitoring system that comprises:

• a light source that produces an interrogation light beam;
• an array of EM sensors positioned above ground or buried underground within an onshore production field and above one or more regions of interest within a subterranean formation, the EM sensors coupled to each other and the light source with at least one optical fiber, wherein at least one of the EM sensors modulates the interrogation light beam in response to an EM signal induced into the subterranean formation by an EM source;
• a processor that couples to and controls the light source, and further couples to and processes the modulated light received from the array via the at least one optical fiber, wherein said EM sensors and said processor collect EM data to produce two or more EM surveys, each EM survey based on data sets collected at different times;
• wherein each EM sensor is physically isolated from a surrounding environment;
• and
• wherein the two or more surveys are combined to produce a time-lapse earth model of the one or more regions of interest.