中文摘要：

在大地震的观测和应急处置中，“费米式”半定量方法发挥着重要作用．文章简要介绍了相关领域中几个有重要应用潜力的半定量方法，包括地震烈度分布的KF模型、用高频能量包络确定大地震的震源时间函数、粗略描述大地震破裂过程的偏振分析方法、地震早期预警中的震级估计，并讨论了这些方法的物理意义和相关的物理问题．

英文摘要：

In the emergency response to large earthquakes, semi-quantitative estimates play a very important role. This article introduces a few examples of such ＂Fermian approaches＂ with their physical significance and underlying physical problems, including the kinematic function （KF） of intensity distribution, the estimate of source time function （STF） of large earthquakes using the high-frequency energy envelope of teleseismic seismograms, polarization analysis for the fast retrieval of the rupture process of large earthquakes,and the magnitude estimate for earthquake early warning （EEW）.