图15  5.0级地震前后小震空间分布

     (M_S≥3.0；42.0°～44.5°N， 85.5°～89.0°E)

      a._1981.1～1986.5；b._1986.7～1990.12

Fig.15  Distribution of small earthquakes before and 

        after the M_S5.0 Urumqi earthquake