张斌^1,,
李小军^1,2,
林国良³,
荣棉水^1,,,
俞言祥²,
王玉石¹,
傅磊²
1. 北京工业大学城市建设学部, 北京 100124
2. 中国地震局地球物理研究所, 北京 100081
3. 云南省地震局, 昆明 650224

基金项目: 国家自然科学基金（51878625），国家自然科学基金地震科学联合基金（U1839202）和中央级公益性科研院所基本科研业务费专项（DQJB21Y42）联合资助


详细信息

作者简介: 张斌, 男, 1989年生, 助理研究员, 主要从事地震动衰减关系等方面研究.E-mail: vincent_zhang0322@163.com

通讯作者: 荣棉水, 男, 1982年生, 副研究员, 主要从事场地效应及强震动观测应用研究.E-mail: waltrong@126.com

中图分类号: P315

收稿日期:2021-06-28
修回日期:2021-08-06
上线日期:2021-10-10

Analysis of strong ground motion characteristics and directivity effect in the near-field for the May 21, 2021 M_S6.4 Yangbi earthquake

ZHANG Bin^1,,
LI XiaoJun^1,2,
LIN GuoLiang³,
RONG MianShui^1,,,
YU YanXiang²,
WANG YuShi¹,
FU Lei²
1. Faculty of Urban Construction, Beijing University of Technology, Beijing 100124, China
2. Institute of Geophysics, China Earthquake Administration, Beijing 100081, China
3. Yunnan Earthquake Agenoy, Kunming 650224, China


More Information

Corresponding author: RONG MianShui,E-mail:waltrong@126.com

MSC: P315

--> Received Date: 28 June 2021
Revised Date: 06 August 2021
Available Online: 10 October 2021


摘要
摘要:利用中国国家强震动观测台网（NSMONS）和云南地震预警台网获得的158组强震动记录，分析了漾濞M_S6.4地震观测的近场地震动幅值、反应谱值特征以及不同周期反应谱值的空间分布.将近场台站反应谱值与NGA-West2预测方程进行对比，结合现场震害调查结果验证此次地震近场地震动的方向性效应.研究结果表明，近场30 km内地震动峰值加速度（PGA）表现出南北向（NS）高于东西向（EW）的方向性差异，PGA最大相差达1.86倍；在水平向加速度反应谱值（SA）卓越周期附近的谱值普遍高于基本设计谱，漾濞台NS向卓越周期对应的SA是罕遇设计谱平台值的3.87倍；空间分布显示，断层破裂前方（震中东南方向）观测的水平向SA显著大于破裂后方，在短周期更为明显，随着周期的增大差异有所减小；破裂前方台站观测的短周期SA大于NGA-West2预测结果，而破裂后方台站观测的SA在整个周期范围内均小于NGA-West2预测结果，表现出显著的方向性效应；震害调查结果也表明近场区域的建筑物破坏呈现NS向破坏较EW向严重的方向性差异.
关键词: 漾濞地震/
近场地震动特征/
空间分布/
方向性效应

Abstract:Using the 158 sets of strong ground motion recordings obtained from the National Strong Motion Observation Network System (NSMONS) of China and the Local Earthquake Early Waring Network of Yunnan Province, we analyse the characteristics of observed near-field strong ground motion amplitude, acceleration response spectra and the spatial distribution of spectral accelerations at different periods for the M_S6.4 Yangbi earthquake. The spectral accelerations of the near-field stations were compared with the NGA-West2 prediction models, and the on-site earthquake damage investigation results were combined to verify the directivity effect of the near-field strong ground motion of the M_S6.4 Yangbi earthquake. The research results show that the peak ground acceleration (PGA) within 30 km in the near-field shows a difference in directionality from north-south (NS) to east-west (EW), and the maximum difference in PGA is 1.86 times; The spectral accelerations near the predominant period of the horizontal acceleration response spectra (SA) are generally higher than the basic design spectra. The SA corresponding to the predominant period in the NS direction of 53YBX station is 3.87 times the value of the rare design spectra platform; The spatial distribution contours show that the horizontal SAs observed in the rupture forward (south-east of epicenter) are significantly larger than that in the rupture backward, which is more obvious in a short period, and the difference gradually decreases with the increase of the period; The short-period SAs observed in the rupture forward is greater than the median predictions of four NGA-West2 prediction models, while the SAs observed in the rupture backward is smaller than the median predictions of four NGA-West2 prediction models throughout the period, showing a significant directivity effect; The earthquake damage investigation results also show that the damage of buildings in the near-field shows a more severe directivity difference in NS direction than EW direction.
Key words:Yangbi earthquake/
Near-field strong ground motion characteristics/
Spatial distribution/
Directivity effect



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