振幅衰减特性在地震与爆破识别中的应用

Amplitude attenuation and its application to earthquake and explosion discrimination

  • 摘要: 基于小震级地震与爆破事件,从快速识别要求出发,分析了P波初动振幅AI和P波最大振幅AP分别与S波最大振幅AS的幅值比判据及其对事件的识别能力.考虑到传播路径对地震与爆破各振幅的影响,选用合理的振幅随距离衰减公式,分别研究了P波、 S波各振幅随震中距的衰减特征,结果显示爆破振幅衰减比地震快; 在100 km处进行衰减校正后重新计算P波与S波幅值比,得到经过衰减校正后的幅值比AI/AS正确识别率从84%提高到98%,AP/AS正确识别率从92%提高到100%,表明经衰减校正后的幅值比判据可以更好地应用于小震级地震与爆破的识别中.

     

    Abstract: Based on the small magnitude earthquakes and explosions and quick identification requirements, this paper analyzed the identification ability of first motion amplitude AI and P maximum amplitude AP to S maximum amplitude AS ratios. Considering the impact of propagation paths on different seismic amplitude, this paper selected reasonable amplitude attenuation formula with distance, and invesigated attenuation characteristics of P, S amplitudes which indicates that amplitude of explosion attenuated faster than that of earthquake. We chosen 100 km as attenuation correction distance and recalculated the ratios of P amplitude to S amplitude after attenuation correction, then it is shown that the correct recognition rate of AI/AS improved from 84% to 98%, AP/AS improved from 92% to 100%. These results show that amplitude ratio criteria after attenuation correction could be better applied to small magnitude earthquakes and explosions recognition.

     

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