“大陆强震机理与预测”中期学术进展  

Academic Progress on the Mechanism and Forecast for Continental Strong Earthquake in the First Two Years

作　　者：张国民[1] 张培震[2] 

机构地区：[1]中国地震局分析预报中心 [2]中国地震局地质研究所

出　　处：《中国基础科学》2000年第10期4-10,共7页China Basic Science

摘　　要：从中国大陆地震的特点出发,提出了活动地块假说,用于描述中国大陆现今构造变形的特征和机制,探索大陆强震的发生机理和预测方法。活动块体是指被大型晚第四纪活动构造带所分割和围限、具有相对统一运动方式的活动地质单元,内部相对稳定,边界带构造活动强烈,深部受不同层次的拆离带或滑脱带所控制,绝大多数7级以上强震都发生在边界带上,而块体本身的运动具有相对统一性。本项目所提出的活动地块假说,从时间尺度上研究晚第四纪(10-12万年)以来的构造活动,着重强调与未来强震活动密切相关的现今时段;从状态上主要研究现今仍在活动、并且与未来强震有关的块体运动及相关的构造变形。根据地震活动、构造活动历史、岩石圈结构、地壳形变图像、地球物理异常及地球动力学背景等的差异,初步将中国大陆划分出5个一级活动地块和19个次级活动地块。不同的活动地块其深部结构是不同的,在全国尺度上初步获取了与活动地块划分方案相对应的中国大陆岩石圈结构的分区差异特征,同时还详细解剖了若干重要活动块体及其边界带的结构特征。GPS测量结果表明不同活动地块的运动方向、速度和变形方式均是不同的。除了初步建立活动地块理论框架之外,本项目还对成组强震与地块活动、剪切断裂的形成和失稳过程。Based on characteristics of large earthquakes in continental China, the project proposes 'active crustal block' hypothesis to describe mechanism of present day tectonic deformation, and to exploit mechanism and methods of predictions of large earthquakes. Active crustal blocks are geological units that have been cut and separated by major quaternary active faults. Each active crustal block moves coherently with very little, if any, internal deformation. Most of tectonic activity takes place along the bondaries of each block. Detachment or decoupled zone develop on the base of each block at different depth. Devastating earthquakes occur along boundaries of active crustal blocks. On the basis of seismicity, neotectonic history, lithospheric structure, crustal deformation, geophysical anomaly, andgeodynamic background, we have preliminarily divided continental China into 5 first order active crustal blocks and 19 second order blocks. Different active crustal blocks respond to different lithospheric structure. We obtained regional distinctions of lithospheric structures in corresponding to the pattern of active crustal block delineation, and studied several important active crustal blocks and their boundary zones in detail. GPS measurements indicate different crustal block move in different direction and with different rates. Progresses are made in the fields of earthquake clustering and blocks movements, formation and instability of shear faults, constitutive relationship of frictions of crustal rocks, brittle-ductile transition and rheology of crustal rocks, relationships of stress distribution, transfer, and earthquake clustering. We also exploit new methods in earthquake prediction and disaster reduction.

关 键 词：中国 大陆 地震预测 强震机理 活动地块假说 地震防御 

分 类 号：P316.2[天文地球—地震学] P315.1[天文地球—固体地球物理学]