断层破裂方式对银川盆地强地面运动的影响  

Influence of seismic source rupture mode on strong ground motion in Yinchuan Basin

作　　者：张冬丽[1] 张伟[2] 徐锡伟[1] 柴炽章[3] 张献兵[2] 

机构地区：[1]中国地震局地质研究所国家活动断层研究中心,北京100029 [2]北京大学空间与地球科学学院,北京100871 [3]宁夏回族自治区地震局,宁夏银川750001

出　　处：《地震工程与工程振动》2009年第4期1-8,共8页Earthquake Engineering and Engineering Dynamics

基　　金：国家自然科学基金项目(40604005);中国地震局地质研究所中央级公益性科研院所基本科研业务专项(DF-IGCEA-0607-1-18);地震科学联合基金项目(A07027)

摘　　要：银川盆地是受断层控制的断陷性盆地,边缘和内部发育了多条断裂带,特别是其内部晚更新世—全新世活动的银川隐伏断层可能对银川市的建设规划和抗震设防影响较大。为了研究银川隐伏断层活动对银川盆地强地面运动特征的影响,本文以银川隐伏活动断层作为目标断层,模拟了断层发生Mw6.5特征地震时,在单侧破裂和双侧破裂两种方式下,银川盆地的强地面运动分布特征。分析结果表明在两种破裂方式下,盆地内强地面运动表现出不同形态的地震条带状分布特征和上盘效应;同时受到银川盆地边缘断裂"西陡东缓"构造特征的影响,地表强地震动分布和断层附近观测点的时程也呈现出独特的盆地边界反射作用。在单侧破裂和双侧破裂两种模式下,近场强地面运动集中区总体上呈现北强南弱的现象,银川市及附近的芦花台等地区是强地面运动分布的主要区域。Yinchuan is a graben-like downfaulted Cenozoic era basin with many fauhs inside basin or along west and east edges. As a late Pleistocene epoch-Holocene active fault, Yinchuan buried fault is one of the active faults which perhaps affect the urban planning and development and earthquake resistance of Yinchuan City seriously, In order to study the influence of Yinchuan buried fault on the strong ground motion in the basin, we simulated the near-field ground motion by means of two rupture modes, unilateral rupture mode and bilateral rupture mode, while the characteristic earthquake magnitude is Mw 6.5. In simulation results, the intensive stripped distribution and hanging wall effect of ground motion appeared with different shapes obviously along the fault trace in terms of two rupture modes. As the influence of Yinchuan Basin structure ＂steep in west edge and gentle in east edge＂, special basin edge effect can be found from some observation point time-histories and near-field ground motion distributions. The major character of strong ground motion is that along the active fault, the ground motion intensity in the north area of the basin is higher than that in south area. So the Yinchuan City and Luhuatai City became two intensive regions of strong ground motion.

关 键 词：银川隐伏断层 强地面运动 数值模拟 破裂方式 

分 类 号：P315.915[天文地球—地震学]