A method for validating earth formation data for input into a geophysical model includes: determining a lithology of the earth formation; receiving measurement data for a plurality of different properties of the earth formation rock; plotting data points for a first property versus a second property in a cross-plot using the received measurement data; plotting an expected correlation between the first property and the second property on the cross-plot for rock of the determined lithology; establishing an acceptance criterion for validating the data points related to the first property and the second property with respect to the expected correlation; determining which of the plotted data points fall within the acceptance criterion to provide validated data points related to the first property and the second property; and inputting the validated data points related to the first property and the second property into the geomechanical model.