针对地震烈度速报工作中快速评估大震断层破裂方向的需求，使用我国西部多个地震的观测资料，根据有限移动源理论，利用趋势面分析方法探讨了震中一定范围内台站初始P波参数的方向差异特征，提出一种利用初始P波快速判定地震破裂断层方向的方法。并通过断层距模型和最小二乘法，统计回归最优拟合参数以确定地震断层破裂方式。通过实际震例对比分析了根据所提方法获得的判定结果与实际地震断层破裂分布的吻合度，证实了方法的可用性。本研究为利用地震实时监测资料快速进行地震断层破裂方向判定提供了新思路，可为地震烈度速报中破裂方向的快速判定和动态修正提供参考。

For the purpose of rapid assessment of the direction of rupture faults in large earthquakes for the earthquake intensity report,we collected observational data from multiple earthquakes in western China,and used trend-surface analysis method to explore the directional difference characteristics of the initial P-wave parameters of the stations within a certain range of the epicenter based on the theory of limited moving sources. Then,we proposed a method for quickly assessing the direction of a seismic rupture fault by using initial P wave and trend-surface analysis. We also put forward a method for determining the fault rupture mode of the earthquake by calculating the optimal fitting parameters of least squares statistical regression by using the fault distance model. Through real earthquake cases,the consistency between the evaluation results of the proposed method and the actual fault rupture distribution is compared and analyzed,which proves the reliability and practicability of the method. The study provides a new idea for the rapid determination of earthquake fault rupture direction using real-time seismic monitoring stations,as well as a reference for the dynamic correction of the results of rapid earthquake intensity report.

P315

国家重点研发计划项目（2018YFC1504501、2017YFC1500400、2016YFC0803109）、国家自然科学基金重点项目（U1434210）共同资助