Estimation of friction parameters on plate boundaries

板块边界摩擦参数的估计

基本信息

批准号：
17540394
负责人：
KATO Naoyuki
金额：
$ 1.98万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

项目摘要

(1) Numerical simulation about interaction between aseismic sliding and earthquakes. We performed numerical simulations of sliding behavior on plate interfaces using laboratory-derived rate- and state-dependent friction laws to understand the effects of aseismic sliding on earthquake occurrence. Considering recurrence rupture of a large asperity, where velocity-weakening friction was assumed, we modeled postseismic sliding propagating slowly outward in velocity-strengthening region around the asperity. From the simulations, we found the property of propagating postseismic sliding, such as the propagation speed, depends on friction parameters, and the propagating postseismic sliding may trigger rupture at small asperities, causing time dependent expansion of aftershock areas. The results indicate that the observations about space-time evolution of postseismic sliding from geodetic data and about time dependent aftershock areas may be useful for estimating friction parameters. Furthermor … More e, the simulations indicate that perturbation in sliding velocity due to rupture of a large asperity significantly affects the characteristics of rupture of small asperities because of time and rate dependence of frictional characteristics. This effect must be taken into consideration in estimating sliding velocity from recurrence pattern of small repeating earthquakes. (2) Analysis of geodetic and seismic data. The spatio-temporal evolution of aseismic sliding on the plate interface below the hypothetical source area of the Tokai earthquake was estimated from GPS data. We obtained the relations between shear stress and slip and between shear stress and slip rate, and velocity-weakening frictional property was estimated from the relations. This is consistent with a model for slow earthquakes on the basis of the rate- and state-dependent friction. The spatio-temporal evolution of aseismic sliding on the plate interface along the Japan trench, northeastern Japan, was estimated from the analysis of small repeating earthquakes. In order to estimate sliding velocities from the data of small repeating earthquakes, the relation between coseismic slip and magnitude is required. The empirical relation for small repeating earthquake is significantly different from that has been used for usual earthquakes, in which stress drop is constant. On the basis of fracture mechanics of an asperity, a theoretical explanation for the empirical scaling relation for the small repeating earthquakes was obtained. Less

（1）我们使用实验室衍生的和状态依赖性定律对板上的板上的板上的板上的滑动行为进行了数值模拟假设摩擦的较大浅层的复发性破裂，我们对模拟围绕模拟的后滑动滑动缓慢地强度缓慢的强度进行了建模令人震惊的是，导致余震的时间依赖性。大量的摩擦特征在估计小型重复地震的复发模式时，会影响摩擦特征的时间和速率依赖性的特征剪切应力和滑动之间的关系与剪切速率和滑移速率之间的关系与速率和状态依赖的摩擦的模型一致。从对所有重复的地震的分析中估算了沿日本trenca的界面。 CH应力下降是基于骨折的裂缝力学，重复地震较少