This research performs a sensitivity analysis of response spectrum values for various physical earthquake parameters, which are used to generate synthetic seismograms consistent with the expected seismicity in north Chile. Sensitivity analyses are based on the earthquake scenario and slip distribution model of the 2014, \(M_w\) 8.1 Pisagua earthquake, and seven other physically plausible interplate events for north Chile. A finite-fault rupture model, and slip distribution of the Pisagua earthquake, were obtained using inversion of InSAR and GPS data. Three other rupture models based on previous studies of interplate locking for north Chile and capable of generating \(M_w\) 8.3–8.6 earthquakes with an estimated maximum slip of 9.2 m, were incorporated in the analyses. Also, four additional scenarios with moment magnitudes in the range \(M_w\) 8.6–8.9 were generated by concatenating these physical scenarios into larger rupture areas within the north segment. Using these scenarios, synthetic ground motions were built at four observation sites: Pisagua, Iquique, Tocopilla, and Calama. Response sensitivity was studied for three key rupture parameters: mean rupture velocity, slip rise-time, and rupture directivity. Responses selected were peak ground displacement (PGD), spectral pseudo-velocities, \(S_v\), and spectral displacements, \(S_d\). First and second order variations of PGD, \(S_v\), and \(S_d\) relative to the source parameters were computed and used together with a Taylor series expansion to propagate uncertainty into the responses as a function of \(v_r\) and rise-time \(t_r\). To study the effect of rupture directivity, three different foci locations were considered for each scenario: north, south, and at the centroid of the slip model. Response PGD values show no clear trends with rupture velocity, \(v_r\); however, the variability increases as the system period increases. The effect of the slip rise-time is significant, and as \(t_r\) increases, the spectral responses tend to decrease, suggesting that shorter slip rise-times lead to higher seismic demands in long period structures. The results obtained for the directivity analysis suggest that two factors control the expected waveforms and spectral responses: first, the direction of the rupture relative to the location of each site, and the hypocentral distance.

本研究对各种物理地震参数的响应谱值进行敏感性分析，这些参数用于生成与智利北部预期地震活动一致的合成地震图。敏感性分析基于 2014 年的地震情景和滑动分布模型、\(M_w\) 8.1 Pisagua地震以及智利北部其他七个物理上合理的板间事件。使用 InSAR 和 GPS 数据反演获得了 Pisagua 地震的有限断层破裂模型和滑动分布。其他三个基于智利北部板间锁定研究的其他破裂模型，能够产生\(M_w\)8.3-8.6 级地震，估计最大滑移为 9.2 m，被纳入分析。此外，通过将这些物理场景连接到北段内更大的破裂区域，生成了四个额外的矩震级在\(M_w\) 8.6-8.9 范围内的场景。使用这些场景，在四个观测点建立了合成地面运动：比萨瓜、伊基克、托科皮拉和卡拉马。研究了三个关键破裂参数的响应敏感性：平均破裂速度、滑动上升时间和破裂方向性。选择的响应是峰值地面位移 (PGD)、光谱伪速度\(S_v\)和光谱位移\(S_d\)。PGD​​ 的一阶和二阶变体\(S_v\)和\(S_d\)相对于源参数被计算并与泰勒级数展开一起使用，以将不确定性作为\(v_r\)和上升时间\(t_r\)的函数传播到响应中。为了研究破裂方向性的影响，每个场景都考虑了三个不同的焦点位置：北、南和滑动模型的质心。响应 PGD 值没有显示出明显的破裂速度趋势，\(v_r\)；然而，可变性随着系统周期的增加而增加。滑差上升时间的影响是显着的，并且作为\(t_r\)增加，谱响应趋于减少，这表明较短的滑动上升时间导致长周期结构中更高的抗震要求。方向性分析获得的结果表明，有两个因素控制着预期的波形和光谱响应：首先，相对于每个站点位置的破裂方向，以及震源距离。