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现有震源定位模型均基于均匀介质,为进一步提高震源定位精度,提出了二层水平介质中震源定位方法。采用惠更斯原理推导折射定律过程中的等时线概念,结合工程中广泛采用的折射点近似确定方法,得到将震源深度与水平坐标分离的走时方程。采用特定的台站分布方案,将走时方程简化为线性方程组。采用合理假设并取几何平均数的方法修正震源深度的计算结果。二层模型在多种定位条件下的计算精度均明显高于经典线性定位方法。对各种定位条件下二层模型的计算结果分析表明,在波速比和台站间距取不同值时,存在定位效果最优的取值范围,且二层模型尤其适用于埋深较大的深震源定位。台站与震源水平、竖直距离比较大时,定位精度变差,建议在地(矿)震易发区布置台站。另外,当震源与台站距分界面距离比过大或过小时较经典线性方法不具优势,建议与经典线性定位法结合使用。二层模型的进一步优化和向多层模型推广,将进一步完善地(矿)震震源精确定位方案。
The existing hypocenter positioning models are based on homogeneous media. To further improve the hypocenter positioning accuracy, a hypocenter localization method is proposed. The concept of isochrones in the process of deducing the law of refraction using the Huygens principle is introduced. Combined with the method of approximate determination of refraction points widely used in engineering, the travel time equation is obtained, which separates the focal depth from the horizontal coordinate. Using a specific station distribution scheme, the travel time equation is reduced to a linear system of equations. Reasonable assumption and take the geometric mean method to correct the source depth calculation results. The calculation accuracy of the two-layer model under a variety of positioning conditions are significantly higher than the classical linear positioning method. The calculation results of two-layer model under various positioning conditions show that there is an optimal range of positioning effect when the wave velocity ratio and the station spacing are different, and the two-layer model is especially suitable for deep depth Source positioning. When the distance between the station and the source is relatively large and the vertical distance is relatively large, the positioning accuracy will be deteriorated. Therefore, it is suggested that stations be arranged in areas prone to earthquakes (mines). In addition, when the source and the station from the interface distance ratio is too large or too small compared with the classical linear method is not advantageous, it is recommended combined with the classical linear positioning method. The further optimization of the second floor model and the promotion to the multi-layer model will further improve the precise positioning scheme of the (mine) epicenter.