Abstract:Information used to evaluate disaster conditions shortly after an earthquake is very limited.To develop fast earthquake emergency response and rescue techniques using aftershock information that can quickly be accessed,the location relationship between the spatial distribution of aftershock activity in different time periods and heavy disaster area of intensity distribution is analyzed by actual investigation after an earthquake.Moreover,considering the influence factors of the seismogenic fault strike,residential area density,landform,and physiognomy in seismic area,the optimum time point of aftershocks statistics can reflect severe disaster areas.To quickly evaluate the severity of disaster areas according to the distribution of aftershocks at the optimum time point with consideration of other influencing factors after earthquakes,improvements can be made in services provided for earthquake emergency rescue.It was determined that the most severe damages occur 3hafter aftershock distribution,and earthquake landform and rainfall disaster damage occur along the direction of aftershock distribution.When a severe disaster area is determined by the aftershock distribution range,adjustments of the long axis direction should be made in reference to the seismogenic fault strike;the direction of the long axis is generally consistent with seismogenic fault direction.Disaster severity is adjusted on the basis of settlement distribution.Therefore,comprehensive analysis of the influence of various factors causing the disaster is necessary for disaster mitigation.