场,源前兆的判别—λ型在地震预报中的应用前景

面对复杂的前兆场,进行场、源区分,确定未来大震位置,一直是地震预报中的难点之一。文献1]首先提出统计物理学中描述系统演化的序参量的整个历程图λ型与大震由孕震、发震和震后的前兆后效过程曲线相类似。λ型的尖锋处相应于临界点或大震发生,尖锋前为对数曲线,尖锋后为急剧下降。根据模拟实验大震震例,进一步研究了λ型与震中距的关系,证明了λ型只有在源区和近源区出现,源外区和远源区λ型将发生畸变,因而提出了λ型和非λ型是判断源、场区前兆的重要指标。最后对λ型产生的物理机制进行了初步讨论。

APPLIED PROSPECTS OF TYPE TO SITE AND SOURCE PRECURSORS IN EARTHQUAKE PREDICTION

In face of the complex precursory field, to do site and source division and determine the location of future large earthquakes,is still one of the difficulties in earthquake prediction. In reference 1, it is first pointed out that the curve of the whole process type for describing systematic hydraulic sequential parameters in statistical physics is somewhat similiar with that of the precursory after effect process of large earthquakes, including seismogeny,earthquake occurrence, and postearthquakes. The peak point of type is corresponded to the critical point, and it shows logarithmic curve in front of the peak point, but decreases abruptly after the point. .Based on the simulated large earthquake cases, a further study is made for the relations between type and epicentral distance, which proves that type only occurs in the focus region or near source region, and while in out -of -source or far -field region, the type would distort in a way. Hence, an important index to judge the source or field precursors is put forward, that is, type is the key index. Finally, a primary discussion from the physical mechanism of type is carried on.