Abstract: There are many kinds of earthquakes in the Three Gorges area,such as tectonic earthquake,mine earthquake,reservoir induced seismicity and so on.And different earthquakes have different characteristics. But as far as this area is concerned,the majority of the earthquakes belong to micro-earthquakes and small earthquakes,so it is comparatively more difficult to identify their causes and types. The Three Gorges seismic network is a very good platform,which offers us very good earthquake data to do some research on the identification.In this paper,time-frequency spectrum method is used to analyze the difference between tectonic earthquake and mine earthquake,and this is the first step.By comparison,it is found there is obvious difference between them.Firstly,the main frequency of mine earthquake wave is lower than that of tectonic earthquake.And the main frequency of the former mainly centers around 2.2Hz,however the latter is around 5.5Hz.Secondly,the frequency component of tectonic earthquake wave is more abundant than that of mine earthquake,the former's energy density spectrum spreads more broadly along frequency and time axes,being 4 times broader than the latter. And it has many frequency segments with intense energy.Thirdly,the maximum value of energy intensity of mine earthquake wave occurs in all wave train earlier than that of tectonic earthquake and the energy decays quickly.

Key words: tectonic earthquake, mine earthquake, time-frequency analysis, Three Gorges region

摘要： 基于三峡数字遥测地震台网记录的数字化波形资料,利用谱图时频分析方法,研究了三峡地区构造地震和矿震波谱的时频特征,发现二者的时频谱特征存在着明显的差异:1)构造地震波主频高于矿震;2)构造地震波的频率成分比矿震丰富,能量密度频谱随频率轴展布较宽,前者带宽是后者的4倍;3)矿震能量强度的峰值在整个波列中出现的时间较构造地震早,且能量衰减较快。

关键词: 构造地震, 矿震, 时频分析, 三峡