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. In the observation and emergency treatment of large earthquakes, the semi-quantitative method “Fermi” plays an important role.This paper briefly introduces several semi-quantitative methods with important potential in related fields, including the KF model of seismic intensity distribution , The high-frequency energy envelope is used to determine the source time function of large earthquakes, the polarization analysis method for rough earthquakes, the magnitude estimation in early warning of earthquakes are briefly described, and the physical meaning and related physical problems of these methods are discussed.