From the conclusion 4, I remove all global sites from the STRC89 data. VF4 data, mostly are southern hemisphere sites and high-latitude sites. He introduced the correlation cofactor matrix between two deformation models. I omit the mathematical details here. The coseismic deformation is easier to be separated from the secular tectonic motion as long as there are multiple measurements spanning over one year before and after the earthquake.
Logarithmic model is supported by the rock mechanics experiments.
Among the three models, only the exponential decay model is convergent with time so that it is separable with the velocity estimate. In reality, however, it is unlikely to expect the crustal rock to break forever. In this model, the parameter D has much clear definition, i.e. the maximum amplitude of the postseismic deformation. I used this modified logarithmic model to estimate the postseismic deformation field after the Landers earthquake. Due to lack of temporal sampling after Landers earthquake, the separability of the postseismic deformation field from the velocity field is small unless strong constraints are assigned to either one of them.