地震前兆复杂性成因机理研究的讨论(一)──地震前兆复杂性的表现形式

STUDY ON GENETIC MECHANISM OF SEISMIC PRECURSORY COMPLEXITY(一)──The manifestation of the seismic precursory complexity

通过国内外成功与失败的震例分析，介绍了地震前兆共性的一面，如在台网具有一定监测能力的地区，如果发生6级以上地震，震前总能或多或少地观测到异常现象．地震越大震前异常越多，分布越广，持续时间越长，异常幅度也较大。同时文章着重对前兆复杂性的表现形式进行了较为系统的归纳、整理，主要从以下几个方面进行了分析：异常与地震关系的不确定性：主要表现在除了“有异常有地震”和“无异常无地震”的理想情况外，还存在“有异常无地震”和“有地震无异常”二种情况；不同地区因地壳结构差异导致前兆时空分布等特征的不同；不同成因类型地震其前兆表现不同；同一地区地震前兆的不重复现象；同一地区地震前兆的不重复现象；地震前兆与后效难以分辨；地震前兆成因上的复杂性；短临前兆异常的多样性；各类前兆变化起始、转折的不同步性。异常空间分布的不均匀性和多变性；异常幅度与震级、震中距无明显确定形式的关系；高潮期中地震前兆与平静期地震有较大差别。并结合地震实例作了简要说明。

This paper has introduced the precursory regularity by means of analyzing the exam-ples of success and failures in earthquake prediction. For example, if an earthquake withmagnitude of more than 6.0 occurs in an area where the network has a certain capability tomonitor the earthquake, we can observe more or less precursory phenomena. The biggerthe earthquake is, the more the precursory anomalies occur prior to the earthquake, thewider the precursory anomalies are distributed, the longer the anomalies last, and thelarger the anomalous amplitude becomes. Meanwhile, the expression form of the precur-sory complexity is emphatically and systematically generalized and arranged. It mainly in-cludes as follows: Uncertainty of relation between anomalies and earthquakes l mainly ex-pressed as 'There is the anomaly, but no earthquake follows” and ”Earthquakes occurredwithout any anomaly prior to themn”；Different precursory features in time and space areshown in different regions ; The precursor even in the same region are not repetitional; Itis difficult to distinguish the precursor from aftereffect; Complexity of the precursory ge-netics j Variety of the short-term and imminent precursory anomalies; Non-synchronism ofprecursory changes in the initial and turning point; Inhomogeneity and multivariability ofprecursors in spatial distributionl Uncertainty of the relation between the amplitude ofprecursory anomaly, earthquake magnitude and epicentral distance; Different characteris-tics of anomalies in active period and quiet period. Combined with earthquake cases theabove-mentioned phenomena are briefly explained in this paper.