摘要
基于汶川地震断层距150 km内56个台站三分量加速度记录分析地震动重要持时的特征,并建立了持时与断层距的拟合关系。与已建立的持时公式比较,以往分析结果都大大低估了汶川地震动持时。近断层特征对地震动持时有显著影响。断层距小于30 km,上盘和下盘场点的持时明显低于平均水平;断层距大于30 km,地震动持时受到下盘效应的影响,持时较长。破裂方向性效应引起地震动持时在垂直断层方向与水平方向上的差异,同时断层破裂前方向场点的地震动持时较短,比破裂后方向场点的持时小近一倍。
56 stations within 150 km to causative fault surface are used as database to analyze the characteristics of the durations of ground motions during the Wenchuan earthquake. A simple attenuation relation in terms of rupture distance is proposed and compared with some available predictions. Previous equations of duration largely underes- timated the durations of ground motions for this earthquake. The near-fauh characteristics have impact upon the du- rations. Within rupture distance 30 km, the durations on hanging wall and footwall are lower than the attenuation re- lation. For the rupture distance larger than 30 km, the durations are strongly influenced by footwall effect. The differences of durations resulting from directivity effects between fault normal and fault parallel are found. Durations of ground motions close to rupture fault are significantly different between the forward and backward direction, and this difference reaches nearly 2 times on average.
出处
《地震工程与工程振动》
CSCD
北大核心
2013年第2期1-7,共7页
Earthquake Engineering and Engineering Dynamics
基金
国家自然科学基金项目(51078117
90815014)
地震行业基金项目(201208013)
关键词
持时
拟合关系
上盘效应
下盘效应
方向性效应
duration
fitting relation
hanging wall effect
footwall effect
directivity effects
