Preliminary correction of the macro epicenter，the direction of the earthquake influence field and the meizoseismal area based on aftershock analysis

In the initial assessment of earthquake emergency response, the accuracy of the judgment of the macro epicenter, direction of earthquake influence field, and the meizoseismal area directly affect the accuracy of the assessment results and the rescue work of the government and relevant departments. This paper collected aftershock sequence in 12 hours, focal mechanism solution and settlement information of M_S6.5 and above earthquakes in Gansu Province and its surroundings in recent years. Through the calculation of aftershock centroids, trend regression, and focal mechanism, etc., the correction method of macro-epicenter location, the direction of earthquake influence field, and the range of meizoseismal area are preliminarily studied. It provides a basis for the rapid development of earthquake emergency rescue work.