加卸载响应比与量纲分析相结合——地震预测的新探索

Dimension Analysis Combined with Load/Unload Response Ratio (LURR)——A New Exploration for Earthquake Prediction

加卸载响应比(LURR)的精髓在于通过能够刻画震源区介质损伤程度的物理参数,来反映地震孕育的进程,从而预测地震。近30年来,人们对加卸载响应比做了大量研究,取得了一系列进展,在地震预测实践中也取得了一定的效果,尤其是加卸载响应比异常区与地震发生的位置有较好的对应性。但是预测效果仍不够理想,其原因主要是:在实际预测中对当地的地球物理情况考虑得不够。我们想到了加卸载响应比与量纲分析相结合的方法,综合考虑当地的地球物理情况,例如剪应变率和平均地震耗散能量等因素的影响。文中选取发生在中国大陆的34个震例资料,通过分析选取与发震震级和时间相关的无量纲量π1和π3,根据对实际数据的拟合,π1和π3均与震级成指数关系。在应用于地震预测实践时,首先根据LURR空间扫描结果选取异常区,然后确定异常区的地球物理参数,再根据LURR时空扫描结果得到Ipp,Tpp和π1和π3,通过π1确定震级M,再由π3确定发震时间Tp,从而形成了系统地预测地震三要素(震源位置,震级和发震时间)的思路。由于该项新方法的数值模拟对于计算提出了更高的要求,因此并行计算的引入非常必需,从而为地震预测工作提供了更强有力的工具。

The essence of Load/Unload Response Ratio （LURR） is to find a physical parameter, with which the preparation process of earthquake through depicting the damage of seismogenic zone can be reflected, and then to predict earthquake. In recent about thirty years since LURR has been put forward, many people have conducted a series researches on LURR, and have got some achievements. In practice of earthquake prediction, LURR has achieved success to some extent. Many earthquakes occurred in the abnormal zone from LURR＇s space-time scanning. But the result is not as well as we wished, the main reason is that we don＇t consider the geophysical condition enough. In this paper, we combine dimensional analysis with LURR method, considering the local geophysical condition, for example the shear strain rate and the average seismic wave energy etc. Using the data of 34 seismic cases which occurred in Chinese mainland, we obtain two dimensionless quantities related with magnitude and the earthquake occurrence time π1 and π3. Through the process of data fitting, the relationships between π1 and magnitude and between π3 and magnitude have been obtained. Applying the result to earthquake prediction, we should determine the seismogenic zone according to LURR＇s space-time scanning result at first; then determining the geophysical parameters of the specific seismogenic, we can get the magnitude and the occurrence time for the future earthquake through πl and π3 separately.