单台地震自动定位网格搜索法及其MATLAB试验

提出了一种利用单个地震台站三分向数字地震波形记录进行单台地震自动定位的网格搜索法。该方法以台站为中心,建立辐射状网格,按可变震中距步长和方位角步长进行搜索。对一个检测到的地震事件记录波形,对每个震中距,计算预测波形特征函数与记录波形特征函数的互相关函数值,选其最大值对应的震中距;对每个方位角,合成沿径向和沿横向的波形分量,并计算P波段的径向绝对积分值与横向绝对积分值之差,选其最大值对应的方位。对于选定的方位,如果合成的径向分量与记录垂直分量乘积在P波段的积分值为负,则取该方位角为震中相对于台站的方位角,否则该角要加上180°。在MATLAB环境中对该方法的基本步骤进行了试验,初步结果表明该方法是可行的。

Grid searching method with single seismic station for automatic earthquake location and a test on MATLAB

A grid searching method with single station for automatic earthquake location, which utilizes 3-component digital waveform records is proposed. The method creates a radial grid with the station as the grid center, and searching is made with varied steps in epicenter distance and azimuth. For the waveform records of a detected earthquake event, a cross-correlation value is calculated between a predicted waveform characteristic function and the characteristic function of the recorded waveform for each given tested epicenter distance, and the epicenter distance corresponding to the maximum cross-correlation value is selected; for each tested azimuth, a radial and a transverse component are calculated from the original N-S and E-W components, and a candidate azimuth is selected that corresponds to the maximum difference between the radial and transverse absolute integrations of the P segment. For the candidate azimuth, if the integration of a product between the calculated radial component and the recorded vertical component of the P segment is negative, then the candidate azimuth is selected as the searched results, otherwise 180 degrees are added to it. A test to the basic steps of the method is made on the MATLAB platform, and a preliminary result shows that the method is feasible.