2020年1月19日伽师M_(S)6.4地震强地面运动特征分析

ANALYSIS OF STRONG GROUND MOTION CHARACTERISTICS OF JIASHI M_(S)6.4 EARTHQUAKE ON JANUARY 19,2020

2020年1月18—19日新疆喀什地区伽师县连续发生3次M_(S)≥5.0地震,其中19日21时发生伽师县M_(S)6.4地震。为更好地了解此次地震的强震动记录特征,分析了此次地震序列的强震动记录,从记录波形上看,位于近场区西克尔强震台获取较大峰值加速度,特别是垂直向有明显脉冲峰值,其水平向有明显脉冲地震动,脉冲周期约为2.78 s,速度脉冲峰值分别为38.1 cm·s^(-1)和36.4 cm·s^(-1),反应了断层破裂的方向性效应。用谱比法分析场地的放大效应,在2 s左右有一个基本的共振周期。通过与喀什地区伽师县设计反应谱对比,西克尔台站的水平向地震动的反应谱远高于喀什地区8度罕遇地震设计反应谱。

On January 18 and 19,2020,three earthquakes with M_(S)≥5.0 occurred in Payzawat County,Kashgar Prefecture,Xinjiang,including M_(S)6.4 earthquake in Payzawat County at 21:00 on January 19.In order to better understand the characteristics of the strong motion records of this earthquake,this article analyzed the strong motion records of this earthquake sequence.From the waveform of the records,the Sikker strong motion station located in the near field area obtained larger peak accelerations,especially with obvious pulse peaks in the vertical direction and obvious pulse ground motions in the horizontal direction.The pulse period was about 2.78 seconds,and the peak velocity pulses were 38.1 cm·s^(-1) and 36.4 cm·s^(-1) respectively,which reflected the directional effect of fault rupture.Using the spectral ratio method to analyze the amplification of the site,there is a basic resonance period around 2 seconds;By comparing with the design response spectrum of Payzawat County in Kashgar Prefecture,the response spectrum of horizontal ground motion of Xikel station is much higher than that of 8 degree rare earthquake in Kashgar Prefecture.