Abstract: The small earthquake activity often presents various anomaly, such as strip, gap, crowd and string etc., during preparing process of a great earthquake. The anomaly reflects the decreasing randomness and the increasing orderness for the samll earthquake activity(microfracture). Here the envolution of small earthquake activity from dis-order to order before great earthquake is studied quantitatively by introducing the concept of information entropy.

Key words: Xinjiang, Wuqia, Information entropy, Earthquake

摘要： 在大地震酝育准备过程中,总是出现种种小地震活动的异常,如条带、空区,成丛、成串等。这些异常从不同角度反映了小地震(微破裂)活动随机性的降低、有序度的增加。本文引入信息熵的概念,定量地研究大震前小震活动从无序到有序的演化,以1983年2月和1985年8月乌恰6.8和7.4级地震为例,表明震前地震信息熵确有明显异常。

关键词: 新疆, 乌恰, 信息熵, 地震