Development of fast-operating servo-controlled loading frame for studying earthquake generating processes

本课题的主要任务是：(1)开发一种新的快速响应伺服控制加载系统，用于在控制不稳定断层运动的同时研究断层本构性质；(2)通过分析断层岩的断层内过程，并通过高温实验产生与深断裂带相同的断层内过程，建立一个真实的断层模型。(3)开展岩石流变学基础研究，提出岩石圈和板块边界流变模型。在本项目正式实施期间，设计建成了一台可在动载至500kN下进行200Hz循环试验的新型伺服控制试验机，并与其他资金建设的卧式压力机和炉相结合，可作为高温（1000‰）双轴试验机使用。该机是传统三轴试验机的扩展，具有良好的渗透率测量能力，为研究深部断层本构特性开辟了新的途径。其他结果如下：(1)在温度随断层正应力的增加而线性增加的情况下（如在地热梯度的情况下），研究了岩盐和岩石-方解石混合剪切带在极端剪切下从脆性变形到中间变形到完全塑性变形的完全转变。否定了以往的断层模型，提出了新的断层与板块边界模型。(2)流变模型揭示了岛弧岩石圈的独特特征，解释了日本岛屿的构造和地震活动。针对比较俯冲学揭示的板块间逆冲型地震的极端变化，提出了一种新的俯冲板块边界流变模型。(3) Harper-Dorn蠕变是基于现有的包括矿物在内的各种材料的实验数据提出的。如果是这样的话，幂律蠕变的预测将发生重大改变。(4)将Shimizu的非平衡热力学理论推广应用于晶内扩散蠕变。少

The main task of the present research project has been (1) to develope a new fast-response servo-controlled loading system for studying fault constitive properties while controlling unstable fault motion, (2) to establish a realistic fault model through the analyzes of intrafault processes in fault rocks and through high temperature experiments producing the same processes as recognized in deep fault zones, and (3) to perform basic researches on rock rheology and propose rheological models for the lithosphere and plate boundaries. A new servo-controlled testing machine capable of 200Hz cyclic testing under the dynamic loading to 500kN was designed and built during the official period of this project, and the machine can now be used as a high temperature (to 1,000ﾟC) biaxial machine combined with a horizontal press and a furnace that were built with other funds. The machine is extended now as a conventional triaxial testing machine with good capability of permeability measurements and w … More ill open ways for studying constitutive properties of deep faults. Other results are as follows.(1) Complete transition from brittle, through intermediate, to fully plastic deformation under extreme shear has been studied for halite and halite-calcite mixed shear zones at temperatures increasing linearly with an increase in the normal stress to the fault (as in the case of geothermal gradient). Previous fault models were all denied and a new fault and plate-boundary model was proposed.(2) Rheological model has revealed unique features of island arc lithosphere and explains tectonics and seismicity of Japanese islands. A new rheological model of subducting plate boundaries was proposed so account for the extream variation of interplate thrust-type earthquakes as revealed by comparative subductology.(3) Harper-Dorn creep was proposed based on existing experimental data on various materials including minerals. Predictions from power-law creep will be changed substantially if this is the case.(4) Shimizu's theory of non-equilibrium thermodynamics was extended and applied to intracrystalline diffusion creep. Less