Seismic reflection/refraction study beneath the Median to the Butsuzo Tectonic Lines

在喜井半岛和歌山西部，沿日本西南外带典型构造带——三巴川-秩父-岛曼托构造线，沿A、B两条线进行了地震反射折射研究。地震线总长度为21公里。主要规格如下：接收点（RP）间隔= 50 m， RP总数= 422，通道= 280，接收器= 9/1RP，源= 3个震源，发射点（SP）间隔= 200 m， RP总数= 422，扫描长度= 16.0秒，扫描次数= 30，扫描频率= 6 40 Hz，记录仪= G-DAPS 4，采样率= 4.0毫秒。，记录长度= 20.0秒。虽然地震线在日本常见的崎岖地形上运行，但地震数据集的质量非常好。初步的蛮力叠加剖面显示出两个主要的水平/次水平反射波，分别为2.5秒和4.5秒，其中2.5秒反射波可能对应于busuzo构造线的基底部分，该构造线将Chichibu带推覆在石曼托带的白垩系层上，而4.5秒反射波可能对应于Gobo-Hagi构造线的基底部分，该构造线将白垩系推覆在石曼托带的古近系层上。然而，由于共同的深度点沿着堆积线和周围不够集中，因此。地震剖面的质量不高。数据处理还需进一步改进。

The seismic reflection I refraction study was made along two lines A and B from the Sambagawa through the Chichibu to the Shimanto belts across the Butsuzo Tectonic Line in the western Wakayama, Kii peninsula, , where the typical structural zonation occurs in the Outer Zone of southwest Japan. The total length of the seismic lines is 21 km. The main specifications are as follows : Receiving point (RP) interval = 50 m, Total number of RP = 422, Channel = 280, Receivers = 9/1RP, Source = 3 Vibroseises, Shot point (SP) interval = 200 m, Total number of RP = 422, Sweep length = 16.0 sec., Number of sweep = 30, Sweep frequency = 6 40 Hz, Recorder = G-DAPS 4, Sampling rate = 4.0 msec., Recording length = 20.0 sec. Although the seismic lines run on rugged topography that is common in Japan, the seismic data set is excellent in quality. The preliminary brute stack sections exhibit two major horizontal / subhorizontal reflectors of TWT 2.5 and 4.5 sec. The 2.5 sec. reflector may correspond to the basal part of the Butsuzo Tectonic Line which thrusts the Chichibu belt over the Cretaceous beds in the Shimanto belt, whereas the 4.5 sec. to that of the Gobo-Hagi tectonic Line which which thrusts the Cretaceous over the Paleogene beds in the Shimanto belt. As the common depth points, however, concentrate insufficiently along and around the stacking lines, the. seismic profiles are not so high in quality. The further improvement of data processing is required.