【摘要】 通过提出应用于广域次声传感器阵列的最小方差法信号源定位模型,分析了阵列信号相关系数特征和本地次声波实时大气传播特性,对阵列阵元数量、阵元组成结构引起的定位误差以及本地次声波的真实大气传播射线进行仿真,并利用中国境内布置的广域次声传感器网络监测到了2013年4月20日四川芦山(雅安)地震的瑞利波激发的本地次声波,验证了上述模型和仿真,结合中国地震台网的国内的地震监测台站数据,从信号走时、信号互相关系数、小波时频图、质点运动轨迹等方面进行了分析与对比,并使用广域最小方差法搜索的算法对次声波和地震波进行定位,结果显示:各次声站点接收到由地震瑞利波引起次声站附近地表震动产生并垂直地表向上传播的次声波,在地震瑞利波之后到达,而且相关系数都达到0.6~0.9,计算得到次声波源方位角为230°(以北京为原点),距离震中小于150km,而且本地次声波受大气传播影响较小,能够较容易的被广域次声阵列探测到,因此地震本地次声波监测能够作为地震监测、研究地面起伏运动与大气波动关系的有效手段.更多还原

【Abstract】 A kind of least-square-error localization algorithm applied on wide spread infrasound network is proposed in this article.Models of cross correlation between distant sensors and atmosphere infrasound propagation are analyzed.The localization error caused by quantity and distribution structure of network and ray tracing of local infrasound in real atmosphere are also calculated.Infrasound coupled by local seismic Rayleigh wave of Lushan(Yaan)earthquake on April 20 th,2013is detected by infrasound network and could prove the algorithm and analysis above.Comparing infrasound signals with seismic recording of IRIS global network,we find that they ware well correlated for the corresponding time period in signal travel time,signal correlation(0.6-0.9),particle motion trajectory analysis,etc..The zone of infrasound source calculated by the least-square-error localizing algorithm is not compact but its center(minimum value determined by least-square-error method)is less than 150 km distant from the epicenter.Due to the less absorption and refraction in atmosphere propagation,local infrasound is easily detected and recognized and could be a possible and feasible way to monitor earthquake and relationship between ground motion and pressure perturbation in atmosphere.更多还原