Kappa ([Formula: see text]) describes the amplitude decay of acceleration Fourier spectrum at high frequencies. Using the records of K-NET and KiK-net stations during the mainshock of the 2011 Great East Japan Earthquake, we examine if the typical measurement method of [Formula: see text] can be extended to this size of event and how propagation path and site condition affect [Formula: see text]. The strength of the linear relationship between epicentral distance and [Formula: see text] is the most apparent in the KiK-net borehole data; for other data sets, the statistical significance of the best-fitting logarithmic model is more tenuous. Our study on site effects reveals that high-frequency amplitudes diminish about 20% at soft soil stations than they do at hard rock stations. The effect on high-frequency filters is around diminution in most cases. And, the effect of nonlinear site response on [Formula: see text] values can be observed.

中文翻译：

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2011年东日本大地震中的河童（κ）

Kappa（[公式：见正文]）描述了高频处加速度傅里叶谱的幅度衰减。利用 2011 年东日本大地震主震期间的 K-NET 和 KiK-net 台站的记录，我们研究了 [公式：见正文] 的典型测量方法是否可以扩展到这种规模的事件，以及传播路径和场地条件影响[公式：见正文]。KiK-net钻孔数据中，震中距与[公式：见正文]之间的线性关系强度最为明显；对于其他数据集，最佳拟合对数模型的统计显着性更为脆弱。我们对场地影响的研究表明，软土站的高频振幅比硬岩站的高频振幅减少约 20%。在大多数情况下，对高频滤波器的影响是在减弱。并且，可以观察到非线性站点响应对 [公式：见文本] 值的影响。