Analysis of dynamic behavior of interactive fault system and estimate of high frequency strong motion

交互断层系统动态行为分析及高频强运动估计

• 批准号: 06680423
• 负责人: YAMASHITA Teruo
• 金额: $ 1.28万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06680423/
• 关键词: fault; crack; strong motion; interactions; rupture; 断層帯; 地震波

The critical slip displacement D_c is defined as the amount of relative slip required for the shear stress to decrease to the residual stress level. It is indicated that there is a discrepancy between laboratory measurements of D_c and values obtained from modeling earthquakes. Our theoretical analysis has shown that the existence of a thick fault zone for natural earthquake is likely to contribute this discrepancy.We also theoretically studied the dynamic nucleation of an earthquake in a fault zone in which small preexisting cracks are densely distributed. Dynamic rupture nucleated in such a zone is significantly influenced by the crack interactions. In general, crack interactions cause two conflicting effects : One is to promote crack growth, and the other to decelerate it. These two are due to coplanar and non-coplanar crack interactions, respectively. Hence if non-coplanar interactions are predominant at the initial state, the crack growth rate is very slow at its onset as shown in our simulations. Observation of seismic quiescence before a large earthquake implies that the assumption that non-coplanar crack interactions prevail at initial state will be reasonable.

临界滑移位移D_c定义为剪应力降低到残余应力水平所需的相对滑移量。结果表明，实验室测量的D_c值与模拟地震所得值之间存在差异。我们的理论分析表明，天然地震的厚断层带的存在可能是造成这种差异的原因，我们还从理论上研究了在小的预存裂缝密集分布的断层带中地震的动态成核。裂纹相互作用对动态断裂的形核有重要影响。一般来说，裂纹相互作用会导致两种相互矛盾的效应：一种是促进裂纹扩展，另一种是减缓裂纹扩展，这两种效应分别是由于共面和非共面裂纹相互作用引起的。因此，如果非共面相互作用在初始状态下占主导地位，则裂纹扩展速率在其开始时非常缓慢，如我们的模拟所示。对大地震前地震平静的观测表明，在初始状态下非共面裂纹相互作用占优势的假设是合理的。

项目成果

山下輝夫: "Apparent critical slip displacement caused by the existence of a fault zone" Geophysical Journal International. 125. 459-472 (1996)

Teruo Yamashita：“断层带的存在引起的视临界滑动位移”国际地球物理杂志 125. 459-472 (1996)。

山下輝夫: "Apparent criticial slip displacement caused by the existence of a fault zone" Geophysical Journal International. 125. (1996)

Teruo Yamashita：“断层带的存在引起的视临界滑动位移”，《国际地球物理杂志》125。（1996）

Y.Umeda: "Possible mechanisms of dynamic nucleation and arresting of shallow earthquake faulting" Tectonophysics. (to appear). (1996)

Y.Umeda：“浅层地震断层的动态成核和阻止的可能机制”构造物理学。

Teruo Yamashita: "Earthquake rupture complexity" Pure and Applied Geophysics. 143. 89-116 (1994)

Teruo Yamashita：“地震破裂的复杂性”纯粹和应用地球物理学。

梅田康弘: "Dynamic nucleation and arresting of shallow earthquake faulting" Tectonophysics.

Yasuhiro Umeda：“浅层地震断层的动态成核和阻止”构造物理学。