前震

临震前震：b值的时间变化

Immediate foreshocks : time variation of the b-value

初动及P波S波振幅比表明，在前震系列中有两种不同的断裂机制。

First motions and ratios of P to S amplitudes indicate that two different faulting mechanisms occurred during the foreshock sequence .

结果表明：在一般的情况下对于前震系列h≤1以及对于余震系列h>1。

The result showed that in general case h ≤ 1 for the foreshock sequence and h > 1 for the aftershock sequence .

前震S波频谱的峰值频率fm及拐角频率fc都明显偏小，因而它们可作为识别前震的两个重要指标。

The peak frequency fm and corner frequency fc of S wave spectra of foreshocks show remarkable decrease which are considered as two vital indexes to distinguish foreshocks .

研究区域内介质品质因子Q＝55～109，前震平均值为93，余震平均值为74；

The results show that in Yongdeng region , the medium Q values range from 55 to 109 , the average Q of foreshocks is 93 , and the average Q of aftershocks is 74 ;

对华东地区（29°～35.5°N，115°～125°E）1970年以来14次MS≥5.0和5次MS≥4.6地震的诱发前震特征进行了研究。

The induced foreshock characteristics of 14 M S ≥ 5.5 and 5 M S ≥ 4.6 earthquakes of east Chinese area ( 29 °~ 35.5 ° N , 115 °~ 125 ° E ) since 1970 have been studied .

通过对地震震源拐角频率fc及地震应力降Δσ随时间变化的统计分析，本文研究结果发现，施甸5.9级主震前的前震序列地震的平均拐角频率明显低于主震后余震序列的平均拐角频率。

Through the statistical analyses of variation of corner frequency f_c and stress drop Δσ with time , it is discovered that the average corner frequency of the foreshock sequences is obviously lower than that of the aftershock sequences .

利用邢台直接前震预报主震

The prediction of the Xingtai main shock by the direct foreshocks

由人工目录检验平静以后的前震导致的地震概率增益

Probability gain due to foreshocks following quiescence tested by synthetic catalogs

前震预报与蠕动破裂的多体相互作用

Many - body interaction of Foreshocks Prediction and Creep Crack

自由振荡能触发可预测地震的前震吗？

Can free oscillations trigger foreshocks that allow earthquake prediction ?

前震和普通震群震源深度分布的比较

Comparison for the Focal Depth of Foreshock and Common Swarm

溧阳两次地震前震活动图象的共性特征

The common characteristics of seismicity pattern for the two earthquakes at Liyang

并认为岫岩5.4级主震可能被前震触发，这为主破裂成核过程提供了一次实例。

It gives one example of the earthquake nucleation process .

没有人能够识别哪些是地震，哪些是前震。

No one has been able to identify which earthquakes are foreshocks .

而34年地震也有大规模前震

and in ' 34 there was quite a large foreshock

江苏及其周边诱发前震初探

Preliminary search for induced foreshocks of Jiangsu and adjacent area

短期阶段中等地震显著增强，震源区出现前震活动；

During the short-term phase , the middle - strong earthquake is active .

这些前震的活动性是与水库水位的变化相关的。

And this activity correlated to changes in the reservoir 's water levels .

66年那次的前震很剧烈

In ' 66 there was quite a large foreshock

永胜地震的前震分析

The Analysis of the Foreshocks for the Yongsheng Earthquake

前震序列地震活动度的异常特征

Anomalous Features of Seismicity Scale of Foreshock Sequences

宁河地区的前震波形特征

Characteristics of foreshock waveforms in the Ninghe region

我们能做的就是提高建筑标准，改进地震前震的监测技术。

What we can do is raise building standards and improve monitoring of foreshocks .

一种可能的短期前震

One possible kind of short & term foreshocks

识别前震余震的单键群方法

Single-Link-Cluster Method to Distinguish the Pre-and After-shocks

华东地区诱发前震特征

Induced foreshock characteristics of East Chinese area

注意有些地震其实是前震，更大的地震可能会接着发生。

Be aware that some earthquakes are actually foreshocks and a larger earthquake might occur .

关于1999年岫岩偏岭5.6级地震前震群序列性质的研究

Study on characteristics of earthquake swarm sequence prior to XIUYAN-HAICHENG MS 5.6 earthquake , 1999

邢台唐山地震前震中附近的地温演变特点

Features of the Geothermal Evolution around the Epicenters before the Xingtai and the Tangshan Earthquake