【摘要】 选取赣中西地区23个ML≥2.0地震的单台波形数据,基于遗传算法,分别采用ω-3和ω-2震源谱模型对每个地震每个水平向的振幅谱进行搜索,得到2组低频水平Ω0和拐角频率fc。目测发现大多数地震震源谱符合ω-3模型,除1个地震的fc接近6 Hz外,其余22个地震的fc均小于3.51 Hz,明显偏低。这23个地震除fc接近6 Hz的这个地震没有出现短周期面波外,其余22个地震短周期面波均比较发育。认为可能是这些地震震源浅造成P、S相干后形成了瑞利型短周期面波造成它们的拐角频率偏低。更多还原

【Abstract】 Based on the digital data of 23 earthquakes with ML≥2.0 in the central and western Jiangxi,we obtained 23 pairs of lower frequency level limit(Ω0)and corner frequencies(fc) by source spectrum models of ω-3 and ω-2,and the genetic algorithm.Comparing with the two source spectra of ω-3 and ω-2 for every earthquake,we find that most of these source spectra are consistant with the ω-3 attenuation model.Their values of fc are less than 3.51Hz.Correspondingly with obvious short-period surface wave.Only one earthquake shows no short-period surface wave with the value of fc of which is about 6 Hz.We believe that the lower corner frequencies are probably resulted from interferences of P wave and S wave radiated from shallow sources.更多还原