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

地震反射I折射研究是沿着两条线A和B线进行的，从三叶川经七步到岛本带穿过Kii半岛西部和歌山的Butsuzo构造线，在那里日本西南部的外带出现了典型的构造分带。地震测线全长21公里。主要参数如下：接收点(RP)间隔=50m，RP总数=422，通道=280，接收器=9/1RP，震源=3次可控震源，炮点(SP)间隔=200m，RP总数=422，扫描长度=16.0秒，扫描次数=30，扫描频率=6 40 Hz，记录器=G-DAP 4，采样率=4.0毫秒，记录长度=20.0秒。虽然地震测线在日本常见的崎岖地形上运行，但地震数据集的质量很好。初步的粗暴叠加剖面显示了行波温度2.5秒和4.5秒的两个主要水平/次水平反射器。2.5秒。反射体可能对应于武藏构造线的底部，该构造线将赤部带推送到岛曼托带白垩纪地层之上，而4.5秒。以戈壁-哈吉构造线为基准，该构造线将白垩纪推覆在岛曼托带的古近系地层之上。然而，由于公共深度点沿叠加线和围绕叠加线不够集中，所以。地震剖面的质量没有那么高。数据处理还有待于进一步完善。

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.