| 2021年云南漾濞6.4级地震近场强震动特性分析 |
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| 引用本文： | 杨黎薇,崔建文,张天继,林国良.2021年云南漾濞6.4级地震近场强震动特性分析[J].世界地震工程,2021,0(4):081-90. |
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| 作者姓名： | 杨黎薇 崔建文 张天继 林国良 |
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| 作者单位： | 云南省地震局, 云南 昆明 650224 |
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| 摘 要： | 选用2021年云南漾濞6.4级地震强震动数据，经校正预处理后，对典型记录的幅值、反应谱和持时进行分析，得到此次地震的地震动特性。结果表明:（1）与我省烈度速报系统自动产出的仪器烈度分布以及实际震害情况相比，近场测点强震动数据所计算出的仪器烈度值与快速仪器烈度分布、现场实际情况基本吻合。（2）三个分量的PGA等值线形态分布大致相似，长轴均沿西北至东南向展开，逐渐衰减，且对于PGA，在近场震中距100 km以内，主震记录高于选用的衰减关系，一定程度上体现了此地震近场高频成分的卓越特性。（3）在震中附近100 km内，结合四个强震动测点距离震中的地理位置可知:随着震中距的增大，地震反应谱峰值周期也在逐渐增大，地震动的高频成分随着距离逐渐衰减。同时，破坏最为严重的区域主要集中在东南方向，其次为西南方向，东北方向基本不受震害影响。（4）此次地震呈中长持时特点，三个分向的持时随着震中距增大而逐渐增加，在震中距超过300 km处逐渐衰减，其中北南方向的持时衰减最快，竖直方向的持时衰减最慢。（5）研究主震地震动持时空间分布，持时受场地条件影响不大，地震破裂主要是沿西北到东南向的右旋走滑，长持时分布在破裂传播方向的东北侧，破裂传播的西北侧持时较短。同时，地震动持时受上盘效应的影响较弱， 在断层上盘和下盘的持时长度没有明显差别， 持时长度都接近拟合得到的平均值。在断层附近持时很小，平均在10s左右。
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| 关 键 词： | 漾濞地震 震中仪器烈度 强地面运动 幅值特性 反应谱特性 相对一致持时 持时空间分布 |
Analysis of near-field strong motion characteristics of the Yangbi M6.4 earthquake in Yunnan province in 2021 |
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| YANG Liwei,CUI Jianwen,ZHANG Tianji,LIN Guoliang.Analysis of near-field strong motion characteristics of the Yangbi M6.4 earthquake in Yunnan province in 2021[J].World Information On Earthquake Engineering,2021,0(4):081-90. |
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| Authors: | YANG Liwei CUI Jianwen ZHANG Tianji LIN Guoliang |
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| Affiliation: | Yunnan Earthquake Agency, Kunming 650224, China |
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| Abstract: | After correcting and preprocessing, the amplitude, response spectrum and duration of the typical Yangbi earthquake (M6.4) in 2021 are analyzed to obtain the seismic characteristics of this earthquake. The results show that:(1) Compared with the instrument intensity distribution automatically produced by the intensity quick report system of our province and the actual earthquake damage, the instrument intensity value calculated from the strong vibration data of near-field measurement points is basically consistent with the rapid instrument intensity distribution and the actual situation of the field. (2) The morphological distribution of PGA isoclines of the three components is roughly similar, and the long axes all spread along the northwest to southeast direction and gradually decay. For PGA, the main strong motion record of Yangbi is higher than the attenuation relationship selected when the Nearfield distance is less than 100km, which reflects the excellent characteristics of the Nearfield high frequency component to a certain extent. (3) Within 100km of the epicenter, combined with the geographical location of the four strong motion measurement points from the epicenter, it can be seen that with the increase of the epicenter distance, the peak period of the seismic response spectrum is also gradually increasing, and the high frequency components of the ground motion gradually decay with the distance. At the same time, the most serious damage area is mainly concentrated in the southeast, followed by the southwest, the northeast is basically not affected by the earthquake damage. (4) The duration of the earthquake is medium to long, and the duration of the three directions gradually increases with the increase of the epicenter distance, and gradually decreases when the epicenter distance exceeds 300km. The duration of the north-south direction decreases the fastest, and the duration of the vertical direction decreases the slowest. (5) The spatial distribution of lateral seismic duration of Yangbi is studied. The lateral seismic rupture is mainly dextral strike-slip along northwest to southeast, and the long lateral lateral rupture is distributed in the northeast side of the propagation direction of rupture, while the lateral lateral rupture is shorter in the northwest side of rupture propagation. At the same time, the influence of hanging wall effect on the duration of ground motion is weak, and there is no significant difference in the length of holding time between hanging wall and footwall of the fault, and the length of holding time is close to the mean value obtained by fitting. The holding time near the fault is very small, averaging about 10s. |
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| Keywords: | Yangbi earthquake seismic instrument intensity strong ground motion amplitude characteristic reaction spectrum characteristics relative unanimity time holding space distribution |
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