广西北流-广东化州MS 5.2级地震地震动峰值加速度特征

Characteristic of Peak Acceleration Ground Motion of the Beiliu-Huazhou MS 5.2 Earthquake in the Junction of Guangxi and Guangdong

利用2019年10月12日广西北流-广东化州MS 5.2级地震中周边50个台站获取的强震动数据,经过基线校正、数字滤波后获得EW、NS、UD三方向的峰值加速度值,对数据的分析后表明:0~30 km范围内,3个方向的峰值加速度衰减明显。而震中距大于30 km的峰值加速度中,大部分的峰值加速度大于东部强震区的峰值加速度衰减关系理论值,只有小部分垂向峰值加速度和个别的水平向峰值加速度小于东部强震区的衰减关系理论值。研究区3个方向的峰值加速度在震中西侧有多中心出现,且其连线成呈现近EW向。研究区断层对本次地震的峰值加速度衰减影响不明显。竖向峰值加速度与两个水平方向峰值加速度有超过1/3的比值大于0.65(35组/100组)。33组数据中只有3组数据的峰值加速度大于0.05g,具有工程设防意义。

Using the strong vibration data obtained from 50 stations around the Beiliu-Huazhou MS5.2 earthquake on October 12^th,2019,the peak acceleration values in the three directions of EW,NS and UD are obtained after baseline correction and digital filtering.The analysis of the data shows that the peak acceleration attenuation in the three directions is obvious within the range of 0-30 km.However,for the peak acceleration with the epicenter distance greater than 30 km,most of the peak acceleration is greater than the theoretical value of the peak acceleration attenuation relationship in the eastern strong earthquake region,while only a small part of the vertical peak acceleration and some horizontal peak accelerations are smaller than the theoretical value of the attenuation relationship in the eastern strong earthquake region.The peak acceleration attenuation in the three directions of the study area has the characteristic of nw-w.The fault in the study area has no obvious effect on the attenuation of peak acceleration.The ratio of the vertical peak acceleration to the two horizontal peak accelerations was more than 1/3 greater than 0.65(36 groups/100 groups).Of the 36 groups of data,only 3 groups of data have peak acceleration greater than 0.05g,which is of engineering fortification significance。