强震孕育发生的大陆活动地块理论未来发展与强震预测探索

Physical basis for prediction of continental strong earthquakes:Development and prospect of active tectonic block theory

1地震预测预报研究的学术高地——强震孕育发生的大陆活动地块理论框架建立地震作为一种重大自然灾害,直接影响着人类生活和自然环境.20世纪中叶板块构造学说的建立,对发生在板块边缘约占全球80%地震的分布特征、形成机制、活动规律、动力过程等给出了合理解释,但是却很难解释发生在远离板块边缘,特别是大陆板块内部成灾性最大的大型、特大型地震[1,2].

Proposed by Chinese scientists on the basis of a synthetic and progressive view of active tectonics,regional seismicity,present kinematics of the crust,and geophysical investigations,the hypothesis that the strong earthquake activity in continental China is controlled by the movement and deformation of active tectonic blocks explains the spatial distribution of strong earthquakes.More specifically,this hypothesis predicts that future strong earthquakes will only occur at favorable locations within the block boundary zones.Through the recent two decades,as a basis for understanding the tectonic activity of continental China and the prediction of strong continental earthquakes,the theoretical framework of the active tectonic block hypothesis has been developed and improved.Moreover,a theoretical model of active tectonic blocks(version 1.0)was consequently constructed,contributing to the transformation from probabilistic prediction toward physical prediction.Earthquake prediction,especially the prediction of devastating earthquakes within continents,has been a most particularly scientific problem worldwide for a long period of time,enticing scientists to make great efforts in corresponding research and thus produce various prediction models and theories.The practice of earthquake prediction as a whole is experiencing transformation in four aspects:from empirical prediction to physical prediction,from deterministic and qualitative prediction to probabilistic and quantitative prediction,from single discipline-based prediction to multidiscipline-based prediction,and from prediction for warning to prediction for protection.The active tectonic block model version 1.0 assumes that strong continental earthquakes concentrate at the active tectonic block boundary zones,which has been evidenced by most of the strong earthquakes in continental China during the past in recent 20 years.As these events became observable in a more exact and detailed way,the content of the active tectonic block model version 1.0 was also enriched.However,many problems associated with the concepts of active block theory and the framework of the active tectonic block model still require solutions.It is well known that the strong earthquakes result from the cycle of progressive accumulation of strain,development of materials instability,and abrupt release of strain energy at particular portions of the active tectonic block boundary zones.Therefore,achieving a breakthrough in earthquake prediction relies on the complete understanding of the physical processes of the entire earthquake cycle.To achieve such a breakthrough,a new version of the theoretical model of active tectonic blocks(version 2.0)developed by improving the existing theories and models is expected.The improvements will focus on the tectonic activity and contemporary deformation of faults within active tectonic block boundary zones,the correlation between near-surface tectonics and deep structures,the dynamic background of the development and occurrence of strong earthquakes,and the physics of the earthquake source.To the aforementioned improvements,this paper suggests various scientific work,including carrying out synthetic research based on multiple methods,developing and improving the theoretical system of the active tectonic block hypothesis,developing dynamic models of strong earthquakes in active block boundary zones with a physical basis,performing research on the mechanics and prediction of strong earthquakes within active tectonic block boundary zones,and eventually establishing and developing testable models of physical prediction of strong earthquakes.