Inverse models/modeling error sources

Note that the abovementioned basic types of sources cannot be located in the second or fourth quadrants of the diamond source-type plot in Fig. 4. Moment tensors located in this area indicate numerical errors of the moment tensor inversion, a more complicated source model or faulting in anisotropic media. 

Finding the source location and the time history of the solute in ground-water can be categorized as a problem of time inversion. This means that we have to solve the governing equations backward in time. Modeling contaminant transport using reverse time is an ill-posed problem since the process, being dispersive is irreversible. Because of this ill-posedness, the problems have discontinuous dependence on data and are sensitive to the errors in data. 

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