Geomorphological Study for Better Prediction of Large Earthquakes Generated by Active Faults

准确评价活动断层再活化引起大地震时的孕震行为的基本数据是活动断层的几何形状、凸起和破裂起始的位置、破裂传播的方向等。为了获得这些数据，我们编制了一个关于断层滑动分布的数据库，该数据库沿着日本的98个主要活动断层带，由地震研究所选择用于日本国家地震危险图委员会，地震研究促进总部。资料来源于2001年以前有关这些断层的文章和报道以及“日本活动断层数字地图”（Nakata和Imaizumi，2002年编辑），并编制成Excel文件，处理成GIS格式。该数据库包括断层位置、垂直滑动、水平滑动、滑动速率估算、断层相关特征及其年龄的测量方法等内容，是国内第一个此类数据库，但还远未达到实质性水平，特别是在滑动速率方面。 ...更多信息 吃数据。但我们认为，该数据库对活动断层上的粗糙体的粗略定位是有用的，以便更好地估计强地面运动。我们还对大比例尺航空照片进行了仔细的解释，以便更详细地绘制活动断层图，特别注意了微小的构造地貌，获得了有关活动断层范围的重要信息，利用激光成像技术获得了典型逆断层的综合特征（日本东北部仙谷断层）和走滑断层（日本中部的Adera断层），并测试了几种从详细的DEM图像中获取断层滑动的方法。我们分析了沿着断层（带）的滑动速率，以找到断层（带）的剖面。大滑动速率分布的特征，假定断面与地下断层面上的微凸体位置相吻合。基于几何判据，如活动断层痕迹的分支特征和沿断层痕迹的垂直滑动分布沿着的特征模式，作为预测未来地震的地表破裂起始位置和破裂长度的工具（Nakata和后藤（1998）），我们提出了未来大地震的动态断层模型。少

Basic data for accurate assessment of seismogenic behavior of active faults when re-activated causing large earthquakes, are geometry of active faults, location of asperities and rupture initiation, direction of rupture propagation, etc. In order to obtain these data, we compiled a database on fault slip distribution along the 98 major active fault zones in Japan selected for National Seismic Hazard Maps for Japan by The Earthquake Research Committee, the Headquarters for Earthquake Research Promotion. Data were collected from articles and reports on these faults before 2001 as well as 'Digital Active Fault Map of Japan' (Nakata and Imaizumi, edited 2002), and compiled as an Excel file, and processed into GIS format. The database contains location, vertical and horizontal slips and estimated slip rates together with method of measurement on fault related features and their ages.This database is the first product of its kind, but is still far from substantial level, especially on slip r … More ate data. However, we believe that this database is useful to roughly locate asperities on active faults for better estimation of strong ground motion.We also carried out careful interpretation of large-scale air-photographs for more detailed mapping of active faults, paying much attention to minute tectonic landform and obtained important information about extent of active faults, that is closely related to the magnitude of future earthquakes.Laser imagery technique is applied to obtain comprehensive features of typical reverse fault (Senya fault in NE Japan) and strike-slip fault (Adera fault in Central Japan), and tested several methods for obtaining fault slip from detailed DEM images.We analyzed slip rate along faults (zones) in order to find section(s) of large slip rate distribution, presuming that section(s) may be coincide with location of asperities on subsurface fault plane. Base on geometric criteria such as branching features of active fault traces and characteristic pattern of vertical-slip distribution along the fault traces as tools to predict location of surface rupture initiation and rupture length of future earthquakes (Nakata and Goto (1998)), we proposed dynamic fault model for future large earthquakes. Less