## 4 Recommendation on Improving the Efficiency of Intensity Measures
### Ground Motion Database, Intensity Measures and Building Response  
We select over 3500 near-field ground motion records from the NGA-West2 database with epicentral distances \(R_{epi}\leq\) 100 km for moderate-to-large earthquakes in the magnitude range \(M_{w}\) 5.0-8.0 (Figure 1). Figure 1 (right) displays the histogram of ground motion records, sorted into magnitude bins 5-6, 6-7 and 7-8. There are a total of 3582 records from 105 events of which 41% are reverse faulting, 22% of strike-slip and the remaining events are normal and oblique mechanisms. Site conditions for these ground motion recordings are site class A-E, based on _Vs30_[92]. The two horizontal components of ground motion are used individually to compute the structural response for different building frame configurations. For the chosen records, we compute ten widely used IMs, categorized as (i) peak ground motion parameters (_PGA_, _PGV and PGD_), (ii) spectral and duration parameters (_SaT_), _ASI_, _VSI_), and (iii) energy parameters (_A\({}_{RMS}\)_, _CAV_, _I\({}_{A}\)_) to accommodate the amplitude, spectral, duration and energy. Figure 2 summarizes the distance dependence of these IMs for the selected ground motion dataset. The solid black line represents the moving window average of IMs. We observe a more rapid distance decay of _PGA_ than for _PGV_; however, _PGD_ remains almost invariant over distance. For spectral measures, a rapid decay with distance for _ASI_ is observed compared to _VSI_. For the three energy measures, we find that _A\({}_{RMS}\)_ and _I\({}_{A}\)_ decrease with distance, while _CAV_ remains almost constant. _Tsig_ increases with distance, as many recording sites are located in sedimentary basins where the intensity of ground shaking and its duration increase with distance due to the slow arriving surface waves. To analyze correlations between IMs and building response, we model two-dimensional (2D) reinforced concrete (RC) frames, considering 18 different symmetric and asymmetric configurations with natural periods varying from 0.14 to 1.55 s. Rayleigh damping is used to model viscous damping in the structures and frequencies corresponding to the first mode and modes (mode at which mass participation exceeds 98%), which are used to evaluate damping coefficients. Table 2 summarizes our chosen building configurations that represent typical RC frames designed according to building code recommendations. Figure 3 and Table 3 describe the geometry and member configurations of three frames. (#3, #9 and #14 in Table 2). Figure 1: **(Left)** Magnitude \(M_{uv}\) versus epicentral distance \(R_{epi}\) for strong-motion recordings in the NGA west 2 database (gray dots). Red points show the dataset used in this study, focusing on the near-fault region with maximum epicentral distance \(R_{epi}\) = 100 km, leading to 3582 records from 105 events. We consider only magnitudes \(M_{uv}\) > 5 to ensure a significant response of the structure; 41% of records are from reverse-slip, 22% each from strike-slip and oblique-slip and remaining from normal slip events. (**Right**) Histogram of records sorted with respect to magnitude. The highest strong motion records fall in 6.0 to 7.0 magnitude category, followed by 7.0 to 8.0 range. Figure 2: Variation of peak amplitude, spectral, temporal, and energy intensity measures with epicentral distance. Black solid lines represent the moving average. \(PGA\) and \(PGV\) decrease with epicentral distance, whereby the attenuation of \(PGA\) is stronger. \(PGD\) follows a constant trend with distance. Spectral intensity measures and energy measures decrease with distance, except for \(CAV\), which remains almost invariant. Significant duration (_Tsig_) increases with distance. Figure 3: Geometric description of Frames #3, #9 and #14 in Table 2. All dimensions are in meters. (a–c) corresponds to short, intermediate and long period structures.