# Seismological and Engineering Demand Misfits for Evaluating Simulated Ground Motion Records
## 4 Engineering Demand Misfits
The result for L'Aquila is larger than the previous two case studies. This observation is in agreement with the results in terms of the seismological GOF scores. Finally, the results for all case studies reveal the consistency between the seismological and engineering demand log-scale misfits and GOF scores. * An obvious variability is observed in both seismological and engineering demand log-scale misfits calculated in terms of alternative ground motion measures and engineering demand parameters. * It is demonstrated that the seismological and engineering demand log-scale misfits are generally in good agreement. The average log-scale misfits corresponding to the seismological parameters for the Erzincan, Duzce and L'Aquila cases are calculated as 0.21, 0.21 and 0.16, respectively. On the other hand, the average engineering demand log-scale misfits are 0.27, 0.28 and 0.23 for the same regions, respectively. The maximum difference between the two types of the misfits is approximately 30 percent which is observed for L'Aquila. For Erzincan and Duzce this difference is 25 percent. * When the log-scale misfits for all engineering demand parameters are compared, it is seen that misfits obtained in terms of either elastic or inelastic seismic input energies are mostly larger than those corresponding to the spectral acceleration responses. This is because energy by definition is a more complex phenomenon. The upper bound of the energy dependent log-scale misfits is computed to be approximately 0.6 that is obtained for Erzincan region. * The GOF score in terms of the seismological and engineering demand parameters are studied in detail. For the 1992 Erzincan records, the average seismological and engineering demand GOF scores are calculated as 57 and 51, respectively. For the Duzce records, the average seismological GOF score is computed as 55 while the engineering response GOF value is 49. For the L'Aquila records, with stations mostly located in stiff soil conditions, the GOF scores in terms of both seismological and engineering demand parameters are estimated to be higher than the previous two case studies. The values corresponding to the seismological and engineering demand parameters are, respectively, 64 and 54. * There is consistency between the results of both seismological and engineering demand log-scale misfits as well as GOF scores. For each case study, as the seismological log-scale misfit decreases, the engineering demand log-scale misfit also takes smaller value. In addition, as the seismological GOF score increases, the engineering demand GOF score also increases. * The stochastic finite-fault ground motion simulation methodology based on the validated input parameters is observed to yield more precise results at stations located in stiff soil conditions. This observation is valid for both seismological and engineering perspectives. * Overall, the engineering demand misfits are larger than the seismological misfits in logarithmic scale. Similarly, the engineering demand GOF scores are generally less than the seismological GOF values. These discrepancies are believed to arise from the additional uncertainties involved in the structural responses. Finally, in this study, a misfit evaluation methodology is proposed which includes both seismological and engineering demand misfit definitions. The proposed approach should be further tested with other simulated datasets in different regions. The presented method and similar approaches will provide a means for quantitative evaluation of simulated ground motion records in engineering applications. This research received no external funding. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.