2016年青海门源6.4级地震强震记录特征分析

Analysis on Characteristics of Strong Earthquake Records of Qinghai Menyuan MS_6.4 Earthquake in 2016

采用2016年青海门源6.4级地震震中周边64个台的加速度峰值和其中10个台的强震波形数据对地震动的衰减、反应谱及垂直分量与水平分量的比值进行了分析。研究结果表明:门源地震动衰减规律基本符合青藏区的地震动衰减关系变化规律,震中距300 km以内,水平向与垂直向地震动衰减速度相近,震中距大于300 km时,水平向比垂直向地震动衰减速度缓慢;在200 km范围内,部分垂直向与南北向PGA比值偏大的台站基本上分布在托莱山断裂和冷龙岭断裂以北的地区。从加速度反应谱三分量的对比分析发现,土层场地与基岩场地相比呈现明显的场地放大效应;反应谱比的凹槽现象说明在工程抗震中应重视垂直向地震动的作用。

Using the acceleration peaks of 64 stations and the strong earthquake waveform data of 10 stations in the area around the epicenter of Qinghai Menyuan MS6.4 earthquake,we analyzed the attenuation of ground motion,the acceleration response spectrum and the ratio of vertical component and horizontal component.The research results showas follows: the ground motion attenuation lawof Menyuan earthquake basically accords with that in Tibetan area.When the epicenter distance is within 300 km,the attenuation speed of horizontal and vertical ground motions are close; when the epicenter distance is greater than 300 km,the attenuation speed of horizontal ground motion attenuation is slower than that of the vertical ground motion.When the epicenter distance is within 200 km,some stations with larger PGA ratio of UD / NS are basically distributed in the north area of Lenglongling Fault and Tuolaishan Fault.Compared analysis on the three- component of acceleration response spectrum,we find that compared with bedrock site,the soil layer site presents obvious site amplification effect.The groove phenomenon of response spectrum shows that the role of vertical ground motion should be paid attention to the engineering earthquake resistance.