Abstract Observation, theory, and intuition all suggest that larger earthquakes should trigger larger landslides. Many factors could contribute to this, including depth-dependent shear strength or non-linearity of ground motion in soils and rock, but we hypothesize that the key characteristics of large earthquakes causing this phenomenon are (in addition to magnitude) the frequency and duration of the strong ground motion. Because of the paucity of site-specific data for detailed analysis, we take a regional approach to this question by analyzing strong-motion records and earthquake-induced landslide (EQIL) inventories from six well-documented earthquakes. Ground motion is characterized using earthquake magnitude and the median durations and frequencies (mean periods) of subsets of strong-motion records relevant to landslide triggering. EQIL inventories are characterized using the median landslide area of the entire inventory as well as the median areas of the largest 1% of the landslides and the largest 10 landslides. We then compare ground-motion characteristics with landslide size statistics to determine possible correlations. Comparisons of all earthquake- and landslide-size statistics show strong positive correlations between landslide size and (1) magnitude, (2) ground-motion duration, and (3) mean period. Although all the ground-motion measures yield highly correlated regressions, mean period appears to be the best overall predictor of landslide size. Landslide modeling using Newmark's sliding-block method also shows that longer mean periods and durations and larger magnitudes correlate strongly with increases in modeled displacements. These results support our hypothesis that increasing period and duration of seismic ground motion are the physical factors driving increased landslide sizes for larger earthquakes. Additional studies including data from a much larger set of earthquakes is needed to confirm the results of this initial study.

中文翻译：

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地震动频率和持续时间对触发滑坡规模的影响——区域观点

摘要 观测、理论和直觉都表明，较大的地震应该引发较大的滑坡。许多因素可能导致这种情况，包括与深度相关的剪切强度或土壤和岩​​石中地面运动的非线性，但我们假设引起这种现象的大地震的关键特征是（除了震级之外）频率和持续时间强烈的地面运动。由于缺乏用于详细分析的特定地点数据，我们通过分析来自六次有充分记录的地震的强震记录和地震诱发的滑坡 (EQIL) 清单，对这个问题采取区域性方法。使用地震震级以及与滑坡触发相关的强震记录子集的中值持续时间和频率（平均周期）来表征地面运动。EQIL 清单使用整个清单的中位数滑坡面积以及最大 1% 的滑坡和最大的 10 个滑坡的中位数面积进行表征。然后，我们将地面运动特征与滑坡大小统计数据进行比较，以确定可能的相关性。所有地震和滑坡大小统计数据的比较表明，滑坡大小与 (1) 震级、(2) 地面运动持续时间和 (3) 平均周期之间存在很强的正相关。尽管所有地面运动测量都会产生高度相关的回归，但平均周期似乎是滑坡大小的最佳整体预测指标。使用 Newmark 的滑动块法进行的滑坡建模还表明，更长的平均周期和持续时间以及更大的震级与模拟位移的增加密切相关。这些结果支持我们的假设，即增加地震地面运动的周期和持续时间是驱动较大地震滑坡尺寸增加的物理因素。需要额外的研究，包括来自更大范围地震的数据，以确认这项初步研究的结果。