自组织临界现象和重整化群方法在中期地震预报中的应用研究

STUDYONpHE NOMENONOF SEL ORG ANlZEDCR ITI CALITYAND REN ORMA LIZATIONGROUPTHE ORYFOR MID-TER M EARTHQUAKEPREDICTION

本文讨论了大震前的自组织临界现象，认为在大地震发生前地壳处于自组织临界状态。不同规模的地震反映地壳中不同尺度裂隙的产生或扩展。设ｐ＿０，ｐ＿１，…，ｐ＿ｎ是不同尺度岩石块体中产生或扩展裂隙的概率，根据重整化群理论，数列｛ｐ＿０，ｐ＿１，…，ｐ＿ｎ｝有极限。其极限值可能是０或１。选定一个临界值ｐ￣＊，如果ｐ＿０＞Ｐ￣＊则Ｐｎ→１；反之，若ｐ＿０＜ｐ￣＊，则Ｐ＿ｎ→０。在地震平静期内，必有ｐ＿０＜ｐ￣＊，而在地震活跃期内，ｐ＿０＞ｐ￣＊。在本文中，作者根据地震资料研究了青藏高原北部地区的临界概率Ｐ￣＊值，得到大震前Ｐ＿０值大约为０．３－０．８，平静期ｐ＿０约为０．１－０．２，所以Ｐ￣＊值约为０．２－０．３．利用重整化群模型给出了Ｐ￣＊为０．２３２４，预报期限为３年。

Earthquakes withdiverse sizes show the form or extension ofdiverse size fractures in the crust which is in a self-organized state. Let P_0,P_1,…,P_nbe the probability of the form or ex-tension of fracture in diverse size roCk bodies with certain scales. According to renormalization group theory,sequence{ P_0,P_1,…,P_n}has a limit that mav be 0 or 1,and if P_0=p_1=…=P_n, the limit will get the constant(p￣*)。The p￣*is a critical value,and if P_0>p￣*then P_n approaches to 1;if P_0<p￣*,P_n approaches to 0。P_0 can be determined by statistics of earthquake catalogue. There should be P_0<p￣* during the earthquake quiet period,and P_0>p￣* during the active,therefore,P￣* can be determined as the value between the quiet period P_0 and the active P_0.Based on the conclution,a lot of renor-malization medels may be calculated and a model that its p* is within the range is choosen to gain a exact p￣* value. To predict earthquake,the P_0 is worked out using recent data and judged if P_0>P￣* not. The data were calculated in northern district of Qinghai-Xizang plateau and the P_0 is about 0.3-0.8 before strong earthquakes,while it is about 0.1-0.2 during quiet. Therefore,the p￣*isabout 0.2-0.3 and the medel that was choosen gives a exact p￣* as 0. 2324. By this train of thought,a new way to predict strong earthquake is established.