一、引言地震区域划分是在一给定区划内,采用一定的指标(震级、烈度、加速度、地震系数等)划分出今后若干年内地震危险性不同的地区。地震区划所要解决的问题包括未来地震的时间、空间(包括震源深度)、强度、频度和地震影响场的地震长期预报。但在目前,这种预报无论是对时间、频度或最大强度都是一个粗略的概率估计或统 I. INTRODUCTION Seismic area division is to divide the areas with different earthquake hazards in the next few years by using certain indexes (magnitude, intensity, acceleration, earthquake coefficient, etc.) within a given area. The problems to be solved by the seismic zoning include the long-term earthquake prediction of the time and space of future earthquakes (including the source depth), intensity, frequency and seismic influence field. However, at present, this type of forecasting is a rough estimate of probability or frequency with respect to time, frequency or maximum intensity