大陆断层脆塑性转化带强度与孕震深度的定量研究  

EMPIRICAL QUANTITATIVE ANALYSIS OF STRENGTH AND SEISMOGENIC DEPTHS FOR THE BRITTLE-DUCTILE TRANSITION OF CONTINENTAL FAULT ZONE

作　　者：雷蕙如 周永胜[1] LEI Hui-ru;ZHOU Yong-sheng(State Key Laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration,Beijing 100029,China)

机构地区：[1]中国地震局地质研究所,地震动力学国家重点实验室,北京100029

出　　处：《地震地质》2023年第1期29-48,共20页Seismology and Geology

基　　金：中国地震局地质研究所基本科研业务专项(IGCEA1813)资助。

摘　　要：大陆断层脆塑性转化带的强度和滑动稳定性一直是断层力学中研究的重点。从20世纪末起,前人针对脆塑性转化带的摩擦和流变特性开展了大量实验和理论研究,探究脆塑性转化带的强度和变形机制随温度、压力、滑动速率等因素的变化规律。文中总结了描述断层脆塑性转化带强度和稳定性的半定量经验方程和定量本构方程,对比了各种模型的优缺点,发现通过数值拟合方法得到的经验模型高估了断层脆塑性转化带的强度,而基于微观物理机制的脆塑性转化带强度模型更符合自然条件下的断层摩擦行为。但现有的微观物理模型还需进一步考虑剪切带中纳米颗粒的动力学影响及不同类型的微观变形机制约束。The strength properties of fault rocks at shearing rates spanning the transition from crystal-plastic flow to frictional slip play a central role in determining the distribution of crustal stress,strain,and seismicity in a tectonically active region.Since the end of the 20^(th)century,many experimental and modelling works have been conducted to elucidate the variation of the strength profile and mechanism of brittle-ductile transition(BDT)with temperature,pressure,and sliding rate.We review the substantial progress made in understanding the physical mechanisms involved in lithospheric deformation and refining constitutive equations that describe these processes.The main conclusions obtained from this study are as follows:(1)The mechanical data and microstructure of friction and creep experiments indicated the transition from brittle to plastic deformation with the increasing crust depth,which not only controls the ultimate strength of the crustal profile but also limits the lower limit of the seismogenic zone.Moreover,based on the variation of rock characteristics,temperature,normal stress and sliding rate,the brittle-ductile transition zone distributes at different depths in the crust.The strength profile consisting of friction law and flow law is widely used to describe the strength and seismicity of the continental crust.However,this profile model is oversimplified in the BDT zone because this area involves a broad region of semi-brittle behavior in which cataclastic and ductile processes occur.At the same time,the model also lacks characterization of the transient dynamic properties of faults.Rate-and-state friction(RSF)law stipulates that the occurrence of slip instabilities(i.e.earthquake)can be linked with the velocity dependence of friction.Therefore,the RSF equations,when applied to the kilometer-scale of fault zones,models incorporation RSF equations can reproduce several important seismological observations,including earthquake nucleation and rupture,earthquake afterslip,and aftershock duration.However

关 键 词：脆塑性转化带 地壳强度 断层滑动稳定性 定量研究 

分 类 号：P313[天文地球—固体地球物理学] P315.2[天文地球—地球物理学]