孕震断层锁固段累积损伤导致失稳的自组织-临界行为特征  

Behavior characteristics from self-organization to criticality caused by cumulative damage leading to instability of locked segments in seismogenic fault system

作　　者：吴晓娲 秦四清[2,3,4] 薛雷 杨百存[2,3,4] 张珂 Wu Xiao-Wa;Qin Si-Qing;Xue Lei;Yang Bai-Cun;Zhang Ke(College of Architecture and Civil Engineering,Beijing University of Technology Beijing,100124,China;Key Laboratory of Shale Gas and Geoengineering,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Institutions of Earth Science,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]北京工业大学建筑工程学院,北京100124 [2]中国科学院地质与地球物理研究所中国科学院页岩气与地质工程重点实验室,北京100029 [3]中国科学院地球科学研究院,北京100029 [4]中国科学院大学地球与行星科学学院,北京100049

出　　处：《物理学报》2018年第20期417-426,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:41572311;U1704243;41302233;41877218)资助的课题~~

摘　　要：弄清锁固段(岩石)破裂过程中自组织临界性的物理涵义,对正确认识地震可预测性问题等具有重要意义.本文指出锁固段破裂过程存在两个临界点,第一临界点为体积膨胀点,是自组织过程起点,在该点锁固段发生可判识的高能级破裂事件,这可视为锁固段宏观破裂前的惟一可识别前兆;第二临界点为峰值强度点,即失稳点,在该点发生通常有明显地表破裂带的大地震.基于以前研究给出的两者之间应变比理论关系以及地震震级与能量约束关系,可预测锁固段在第一和第二临界点处发生的某些标志性地震,并已得到诸多震例分析的支持.本文研究结果表明:由于锁固段是非均匀介质,其失稳前必须出现自组织过程,自组织是"因",临界失稳是"果",正是因为自组织过程的存在,才使得对某些大地震(如标志性地震)的预测成为可能;两个临界点之间的破裂演化过程并不是瞬态行为,通常是一个长期过程,该过程中标志性地震的发生遵循确定性规律,并不存在小地震直接导致大地震(如标志性地震)的级联效应.Each of the seismogenic locked segments in a well-defined seismic zone can accumulate high strain energy to bring about a major earthquake. Hence, better understanding the physical implication of self-organized criticality in the locked segment（rock） failure process is crucial to achieving insights into such issues as earthquake predictability and so on. We point out that there exist two critical points in the locked segment fracturing process. The first critical point is volume expansion point, which is the starting point of self-organization, at which a rupture event with high energy occurs. It can be regarded as the only identified precursor to macroscopic rupture of locked segment. The second critical point is the peak strength point, namely, the instability point, at which a major earthquake which is able to generate obvious surface rupture zones takes place. According to our previous research on the theoretical relationship of strain ratio between the two points as well as the constrained expressions concerning earthquake magnitudes and elastic strain energy, also known as the theory about the brittle failure of multiple locked segments in a seismogenic fault system, we can predict some characteristic earthquakes occurring at the first and the second critical point of locked segment, e.g., the 2004 SumatraAndaman M_W9.0 earthquake in Indonesia, the 2008 Sichuan MS8.1 earthquake in China, and the 2011 Tohoku MW9.0 earthquake in Japan. This was obtained by retrospectively analyzing the earthquake cases in 62 seismic zones covering the circum-Pacific seismic belt and the Eurasia seismic belt. The present results show that the self-organized process before the locked segment（rock） instability must arise due to its heterogeneity; there exists a causal link between the selforganization and criticality; it is possible to predict some large earthquakes（e.g. characteristic earthquakes） just because of the existence of self-organized process. We emphasize here that the damage process between the two criti

关 键 词：自组织 临界失稳 沙堆模型 锁固段 

分 类 号：P315[天文地球—地震学]