江西永平爆破北西测线资料再解释

本文利用江西永平爆破北西测线深地震测深资料,综合分析了其走时、振幅及频率特性,得到江西东北部地壳结构。利用振幅特性来减少反演的非唯一性。关于振幅特性分析,第一步用经典射线理论分析这一地区的振幅响应趋势;第二步用波动理论方法严格计算临界点附近的振幅特性,进一步研究经典射线理论方法的应用可能。最后还利用隧道波理论分析了永平爆破资料,得出这一地区的地壳上部可能存在低速层;地壳深部可能存在高速薄层,厚度在1km以内,速度为7.40km/s左右;莫霍面顶部为一梯度层结构。结果表明,既使在较稳定的地台区,地壳内部的结构也可能是相当复杂的。

REINTERPRETATION OF THE DATA FROM THE NW SURVEY LINE OF YONGPING EXPLOSION

In this paper, the deep seismic sounding data from the NW survey line of Yongping explosion are used to analyse the travel time and the characteristics of the amplitude and frequency so that the crustal structure of the northeastern part of Jangsi Province is obtained. The characteristic analysis of the an amplitude is divided into two steps. First, we use the classical ray theory to analyse the response tendency of the amplitude to this region. Then using wave theory, we calculate the amplitude character near the critical point, and explore the further possibilities of using the classical ray method. Furthermore, in this paper we use the tunneling wave theory to analyse the data. We conclude that there possibly exist a low velocity zone in the upper crust along the survey line, thin high-velocity layers of a velocity of about 7.4 km/s, whose thickness is-within 1 km, in the deeper crust, and the structure of the gradient zone at the top of Moho boundary. The results also indicate that even in a more stable platform area, the structure of the crust interior can also be quite complicated.