2017年3月27日云南漾濞5.1级地震强震动记录特征初步分析

The characteristics of strong motion records of Yunnan Yangbi M_s5.1 Earthquake on March 27,2017

对"国家强震动台网中心"在2017年3月27日云南大理州漾濞县5.1级地震中获取的15组强震记录进行整理、基线校正和滤波等常规处理,分析记录的幅值、持时以及频谱特征。结果表明,此次地震记录到的强震记录PGA普遍偏小,PGA范围1.3~14.9 cm/s^2,距离震中位置最近的乔后台(53EQH)记录到了最大PGA值,整体PGA值低于本文选取的基岩地震动衰减关系Yu13和BA08。计算了5%~75%和5%~95%两种重要持时,结果显示持时符合随震中距的增大而增大的规律。所有台站的加速度反应谱峰值偏低,都处在50 cm/s^2以下,4个PGA较大台站的加速度反应谱整体低于我国6度多遇地震的抗震设计反应谱,且H/V谱比分析的结果显示场地效应导致了53YBX和53EYS台站加速度反应谱在0.5~1.0 s周期范围内放大现象。

A total of 15 three-component acceleration data from the Ms 5.1 earthquake occurred on March 27, 2017 in Yangbi County, Yunnan Province, China recorded by China Strong Motion Net Center（ CSMNC ）were analyzed and processed, including the base lines correction and filtering, used for comparing the characteristics of the ampli- tude, duration and response spectra of the strong motion records. The results show that PGA of data are small on the whole records, ranging from 1.3 ~ 14.9cm/s2, generally lower than selected bedrock ground motion attenuation relation Yul3 and BA08, and the largest PGA 14.9 cm/s2 was recorded by the closest station, Qiaohou Station （53EQH）. 5% -75% and 5% ~ 95% significant duration were calculated and increased with the epicentral dis- tance. The acceleration response spectrums of all the stations are at a low level, under 50cm/s2, and the four lar- gest PGA response spectraare also smaller than seismic design response spectrum of 6 degree frequent earthquakes in China, and the results of the analysis of H/V spectral ratio show that site effect lead to the amplification of accel- eration response spectrum between the period of 0.5 and 1.0s at 53YBX and 53EYS station.