论文部分内容阅读
本文根据调制小震法对我国近年来发生的15次中强地震(M=5.5～6.9)和5次强震(M=7～7.9)进行了总结。结果表明,在具有一定地震活动水平的地区,以及台网控制较好的地区,调制小震法对判断中、强震发生的位置,强度和粗略的发震时间可能会起到一定的作用。得到的初步结果如下: 1.强震一般发生在调制小震带之间的空段内,空段的位置与长度一般与强震的震源体相当。因此由空段的位置和线性尺度可估计未来大震的位置和震级。 2.中强地震一般发生在调制小震带端部或两个调制小震带交汇区附近以及调制小震相对集中的地区。但较大震级的中强震前有调制小震带显示的空段。 3.中、强震前半年至一年内调制小震向震源区附近集中,频次增高,并出现调制小震比超过自然概率。由此可估计中、强地震来临的初略时间。 4.调制小震带的方向大多与主震的一个或两个P波节面走向一致。因此由调制小震带的方向可以研究未来中、强地震的震源应力场。
In this paper, 15 moderate-strong earthquakes (M = 5.5 ~ 6.9) and 5 strong earthquakes (M = 7 ~ 7.9) occurred in recent years in our country are summarized based on the modulated small earthquake method. The results show that the modulation of small seismic method may play a role in judging the location, intensity and rough seismogenic time of moderate and strong earthquakes in areas with a certain level of seismic activity and in areas with good network control. The preliminary results obtained are as follows: 1. Strong earthquakes generally occur in the empty space between the small earthquakes and the location and length of the empty earthquakes are generally equivalent to that of the strong earthquakes. Therefore, the position and magnitude of future large earthquakes can be estimated from the location and linear scale of the empty segment. 2. Strong earthquakes generally occur at the end of the small earthquakes in the modulation or in the vicinity of the intersection of two small earthquakes and the areas where the modulation of small earthquakes is relatively concentrated. However, a large earthquake before the earthquake with a small earthquake zone shows the empty section. 3. Medium and small earthquakes within the first half year to one year of strong earthquakes are concentrated in the vicinity of the seismic source area with an increasing frequency, and the ratio of modulated small earthquakes exceeds the natural probability. From this can be estimated in the strong earthquake the beginning of the first time. 4. Modulation of the direction of a small earthquake zone mostly with one or two P wave nodal plane toward the same. Therefore, it is possible to study the source stress field of moderate and strong earthquakes in the future by modulating the direction of small seismic zones.