Clearing the Confusion: - Understanding Precision, Accuracy and Error for Both Inversion and Imaging Methods

adds further complexity to the semantics of separating bias from the random component of error. In this paper, • We attempt to clarify the meaning of uncertainty, precision, accuracy and error for different location methodologies using the scientific literature, and discuss the issues of precision bias and other logical fallacies • We describe a set of monitoring scenarios, then compare event accuracy obtained using (i) an imaging method based on a surface network geometry and (ii) an inversion method based on a down-hole wireline tool geometry . We show for each scenario which method offers the better solution. By doing so we provide some general guidelines on which monitoring scenarios are best suited to which monitoring objectives In conclusion we recommend that all parties are vigilant in using appropriate terminology and consider the objectives of any monitoring project, prior to deciding upon the network geometry. We advise that any decision to carry out a monitoring project is considered in the light of the nature of the sub-surface velocity field and the extent of our knowledge of this velocity field. With such consideration in mind one can decide whether this knowledge is likely to be sufficient to answer the project objectives in a constrained and meaningful fashion.