图13  甘肃及邻近地区小震调制比、b值和频度扫描图（1987.4.1～9.30）

     Ⅰ―张掖、甘肃交界异常区；Ⅱ―西礼盆地西缘―甘川交界异常区

Fig.13  Scanning map of ragulatory ratio，b-value and 

        frequencyof small earthquakes in Gansu province 

        and its adjacent area