海城、岫岩地震序列非线性结构特征及判定前震序列的时间结构变异诊断法

The time-frame coefficient method to diagnose nonlinear characteristics of earthquake sequences in Haicheng-Xiuyan Region, Liaoning Province

运用地震序列非线性关系和时间结构变异系数 ,对辽宁海城、岫岩从 1 975年以来 4次显著地震 (1 975,MS7.3;1 978,MS5.9;1 988,ML 3.7震群 ;1 999,MS5.6)的地震序列进行了对比研究 ,结果表明 ,前震序列、余震序列及一般小震群 ,在时间结构特征上有明显的差异。前震序列时间变异系数 δ≈ 1、余震 δ>1。只有当该区发震系统的行为具有足够的随机性时 ,才会以主震和余震方式进入新的能量大释放状态和阶段 ,这是一个复杂系统时间不可逆过程的特殊结构和基本特征 ,因此提出了前震序列时间结构变异诊断方法。同时 。

Using the nonlinear relations and the time-frame coefficient of earthq uake sequence, the four earthquake sequences (1975, MS 7.3; 1978, M S 5.9; 1988 ML 3.7 swarm; 1999, MS 5.6) occurred in the Haicheng-Xiuyan region of Liaoning Pr ovince since 1975 are studied. The result indicates that there are evident diffe rences among the foreshocks sequence, aftershock sequence and small normal swarm s in the time-frame characteristics and the time-frame variation coefficient ( δ).δ≈1 for a foreshocks sequence, and δ1 for an aftershock. A new state, a sta ge of large energy release with a main earthquake and many aftershocks come about when the behavior of the earthquake generation system of a region is of enough r andomness, which is the special frame and foundational nonlinear features of a c omplex system with the irreversible process. A time-frame variation coefficient method to diagnose the forerunner earthquake sequence is consequently proposed. A similar study of different types of seismic activity states and nonlinear time -frame relation earthquake sequences that occurred in other regions are also pr esented.