Faulting process and strong ground motion predicted from crustal deformation

1)长垣-日府断裂周围的地壳形变根据日本地理调查局GPS地球观测网的观测记录，研究了长垣-日府断裂周围的地壳水平形变。将由三个GPS观测点组成的三角形作为有限元的三角形单元，利用有限元中的应变计算技术，估算了地壳形变的应变率。应变率的大小在空间上是不同的，但主应变率方向几乎垂直于断层走向。这一结果表明长町-日府断裂是逆冲断裂。2)长垣-日府断裂破裂的模拟。从理论上提出了一种利用由…得到的参数的经验公式来估算断层参数的方法更多的岩石破裂实验，并考虑了地壳中温度和初始应力的变化。利用该方法建立了长垣-日府断裂的有限元模型。通过将地壳形变作为规定的位移施加到有限元模型的侧边界上，对断层进行破裂模拟。模拟得到的地面加速度时程存在一定的数值误差。3)断层滑动停止后的粘滞相为了克服上述数值问题，在块体滑块模型的基础上发展了一种数值方法。这项技术允许模拟粘滞模式。为了验证所提出的数值方法的有效性，将数值结果与块滑块模型稳态简谐运动的精确解以及块滑块试件的振动实验结果进行了比较。该方法对精确解和实验结果进行了模拟。较少

1) Crustal deformation around the Nagamachi-Rifu faultsThe horizontal crustal deformation around the Nagamachi-Rifu faults was investigated from the records observed by GPS earth observation network of the Geographical Survey Institute. The strain rates of the crustal deformation were estimated by taking a triangular composed of three GPS observation points as a triangular element of finite element method and using the technique of strain calculation in finite element method. The magnitude of the strain rate varied spatially, but the major principal directions of the rates were almost perpendicular to the strike of the faults. This result indicates that the Nagamachi-Rifu faults are thrust faulting.2) Simulation of fault rupture of the Nagamachi-Rifu faultsA method for evaluating the fault parameters such as breakdown shear stress, breakdown stress drop, and critical slip displacement on fault surface was developed theoretically by using empirical equation of the parameters obtained fr … More om breakdown experiments of rocks and taking the variations of temperature and initial stress in crust into account. Using the method, the finite element model of the Nagamachi-rifu faults was build. We performed the rupture simulations of the faults by applying the crustal deformation to the lateral boundaries of the finite element model as prescribed displacement. The numerical errors were observed in the time history of acceleration on the ground obtained from the simulation. The errors seemed to be caused by the numerical problem that the joint elements adopted as fault model is incapable of simulating stick phase after cease of sliding.3) Stick phase after cease of fault slidingTo overcome the above numerical problem, a numerical technique was developed on the base of block-slider model. The technique permit to simulate the stickmode. In order to validate the proposed numerical technique, the numerical results were compared with the exact solutions of block-slidermodel for harmonic steady state motion and the results obtained by the vibration experiments of block-slider specimen. The proposed method simulated the exact solutions and the experimental results. Less