Magnitude and distance distribution of strong aftershocks in Sichuan-Yunnan region

摘要

Using the earthquake sequences data with Ms≥6.5 since 1966 in Sichuan-Yunnan region, we research the charac- teristic of the magnitude difference distribution between main shocks and their strong aftershocks; and then study the spatial distribution characteristic of the strong aftershocks away from their main shocks. The result shows that the magnitude difference distribution obeys intercepted exponential distribution, while the spatial distribution of strong aftershocks obeys normal distribution and the dominated distribution area of strong shocks is 10～39 krn away from main shock. Finally the probability density function of the magnitude difference distribution and the spatial distribution of strong aftershocks is deduced.