NOVELTY - The method involves determining a parameter associated with a subsurface hydrocarbon e.g. oil, reservoir location based on ratio data from a set of orthogonal spectral components of naturally occurring low frequency background seismic data e.g. monitoring fluid flow. The parameter is stored in form for display. The ratio data is calculated to represent vertical spectral components as a numerator with horizontal spectral components as a denominator. The ratio data associated with the presence of subsurface hydrocarbons are greater than a preset threshold value of 1.5. USE - Used for determining parameters associated with a subsurface hydrocarbon reservoir location of seismic data acquisition area by a computer, for processing and displaying seismic data e.g. monitoring fluid flow, estimating shear-wave velocities, site zonation and shear-wave amplification studies, that is utilized for hydrocarbons e.g. oil and gas, for earthquake hazard surveys, and for monitoring hydraulic fracturing during reservoir stimulation and inversion for earth structure. ADVANTAGE - The ratio data is calculated to represent vertical spectral components as the numerator with horizontal spectral components as the denominator, so that the presence of hydrocarbon reservoirs is indicated, thus mapping potential hydrocarbon-bearing areas within a survey area to optimize exploratory well locations and to minimize costly non-productive wells. The method reduce the time from mineral discovery to production if a total time required to evaluate and explore a survey area is reduced in an economical, low environmental impact, and relatively efficient manner with rapid data acquisition and processing. The method maximizes the production of the hydrocarbons after the detection of the subsurface hydrocarbon reservoir. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:(1) a computerized method of mapping a subsurface hydrocarbon reservoir(2) an information handling system for determining the presence of subsurface hydrocarbons associated with an area of seismic data acquisition(3) a system for subsurface hydrocarbon reservoir mapping(4) a set of application program interfaces having a set of instructions for detecting a subsurface hydrocarbon reservoir. DESCRIPTION Of DRAWING(S) - The drawing shows a schematic illustration of a method for determining parameters associated with a subsurface hydrocarbon reservoir location.