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1984年8月,在大陆深钻计划(KTB)场地勘探的测网内、德国西南的黑林山地区(Black Forest)进行了深地震测深试验。这些场地勘探的方法包括地震折射和地震反射。本文主要讨论沿一条长240km测线上地震折射的解释结果,该测线大致沿黑林山南北向的地貌轴、向南延伸到瑞士的磨拉石盆地内。根据可利用的地震折射资料,得出地壳和地幔顶部的一个详细的速度-深度模型。每一炮记录上都能观测到一个清晰的、速度为5.9km/s、来自基底的折射震相,其后是来自一个低速带顶部里面的反射震相。这个低速带在黑林山北中部地区下方是非常明显的,它的特征是速度值从6.2km/s降至5.4km/s,其分布范围大约在8—14km之间。向南,速度下降逐渐变缓。在黑林山南区中部下方,上地壳的优势速度约为6km/s。低速带下边界处开始出现的下地壳,在记录剖面上呈现出一种很复杂的响应。由于在震中距大约30—70km处、走时1.5—3.5 s之间(折合速度6.0km/s)出现了一些长的混响,所以不可能进行经典的震相对比。根据宽角和近角反射资料的综合解释,认为下地壳的特征是一些高、低速层交替的薄层叠加。这些叠层区的平均速度为6.7km/s。在震中距大于60km的区域,最明显的是来自25—26km深的莫霍里面的反射。
In August 1984, a deep seismic sounding test was conducted at the Black Forest in southwestern Germany on the KTB site survey network. Methods for the exploration of these sites include seismic refraction and seismic reflection. This paper mainly discusses the interpretation of the seismic refraction along a 240km line, which extends along the north-south geomorphic axis of the Hailin Mountains and extends southward into the molasse basin of Switzerland. Based on the available seismic refraction data, a detailed velocity-depth model is derived from the top of the crust and mantle. A clear, refractile phase from the substrate at 5.9km / s can be observed on each shot, followed by the reflected phase from the top of a low velocity band. This low-velocity zone is evident below the central Black Forest northern region, and is characterized by a decrease in velocity from 6.2 km / s to 5.4 km / s with a distribution range of approximately 8-14 km. South, the rate of decline gradually slowed down. Below the central part of the southern Heili Mountain, the dominant velocity of the upper crust is about 6 km / s. The lower crust, which began to appear at the lower boundary of the low velocity zone, presents a complex response to the recorded profile. Since there are some long reverberations between 1.5-3.5 s in the epicenter at a distance of about 30-70 km and a travel speed of 6.0 km / s, it is not possible to perform classical seismic phase contrast. According to the comprehensive interpretation of wide-angle and near-angle reflection data, it is considered that the characteristics of the lower crust are the thin layers superimposed by alternating high and low velocity layers. The average velocity of these lamination areas is 6.7 km / s. In the epicenter more than 60 km away from the area, the most obvious is the reflection from the Moho inside 25-26 km deep.