## 3 Ground Motion Selection Techniques
### Selection Based on Seismological and Site Characteristics  
Several methods were initially proposed to select ground motions based on magnitude and epicentral distance. [PERSON] et al. [62] developed a database of records with sets based on magnitudes and site distances. As expected, earthquake magnitude is an important factor for earthquake selection in other studies ([PERSON] and [PERSON] [63], [PERSON] et al. [64]). It is common for the search window range of magnitude and distance to be adjusted in order to include more records. Magnitude ranges of \(\pm 0.2\)\(M_{w}\) and \(\pm 0.25\)\(M_{w}\) are proposed by [PERSON] and [PERSON] [63] and [PERSON] et al. [64]. [PERSON] and [PERSON] [65] demonstrated that selection based on magnitude and distance is not justified. For this purpose, [PERSON] and [PERSON] [65] analyzed two classes of records for a target site (\(M_{w}\) = 7.0 and \(R\) = 20 km). One class of records is chosen based on magnitude and epicentral distance, while another class of records is chosen arbitrarily from an earthquake catalogue, but scaled. Generally, scaling is performed so that spectral values at natural periods of structures are closer to UHS at those periods. These records were subjected to different SDOF and MDOF structural systems with different natural periods and configurations, hysteresis relationship and material of construction (reinforced concrete and steel). In terms of building response from these two sets, no significant difference was detected to justify a careful selection of records. In addition, [PERSON] and [PERSON] [66; 67] demonstrated that displacements of nonlinear structural elements are independent of epicentral distance. Nevertheless, magnitude and distance are still used in practice for initial selection of records, at least when they are readily available. In record selection, the soil profile is also considered if available. Depending on the velocity layers of the soil beneath the building, ground motion may be amplified or demplified. \(V\)s30, time-averaged shear wave velocity in the top 30 m, is usually used to represent the soil characteristics. Based on \(V\)s30, seismic codes characterize the type of soil in different categories such as rock, stiff soil, and loose soil (NEHRP). [PERSON] and [PERSON] [68] discovered that when soil type is used to select records from a strong motion database comprising 1600 records from 1933 to 1995, the number of records available for selection is dramatically reduced. In addition to the factors discussed above, strong motion duration is critical for building performance and has to be included when choosing ground motions. However, strong motion duration depends on the rupture duration (the time it takes from the onset of the rupture process until it is completed) on the causative fault, and thus, it is already partially considered in magnitude (larger-magnitude earthquakes have longer rupture duration). We remark that the effect of strong motion duration also depends on the demand indexes that are considered. For example, duration has no effect on peak deformation parameters but affects hysteretic energy and the number of cycles. ASCE Standard 4-98 [69] proposes to take a record's duration as an indication of the ground motion at a site at a given seismic hazard level. Furthermore, the seismotectonic settings need to be accounted for, as they also affect strong ground motion. [PERSON] et al. [70] demonstrated that ground motions at the surface of buried faults are stronger than those at the surface of surface ruptures at 1 s periods. Furthermore, shallow-crust earthquakes show different peak and spectral amplitudes versus subduction zones ([PERSON] and [PERSON], [71]). Therefore, these parameters should be considered when selecting a ground motion. As a result of these constraints, the pool of records is significantly reduced during the selection process. In several studies, however, similar ground motions and underlying source mechanisms have been found for earthquakes in different regions ([PERSON] et al.