Radial Vp on Core Samples of the KTB Main Hole HB1a

Ultrasonic wave propagation through core samples is studied in a water tank to insure good signal transmission between transducer, rock specimen and receiver and to avoid time - consuming mechanical preparations. A specifically designed instrumentation was used, which allows to measure the radial p-wave velocity in the plane normal to the core axis and, if the core sample is long enough, also the axial p- and s-wave velocities by common mid-point (CMP) refraction experiments, with water as the upper and the core as the lower layer. By rotating the cores, all measurements are performed for variable azimuths. Computer control of all mechanical and electronical operations, digital 10-bit data aquisition, signal stacking and interactive seismogram evaluation are essential features of the system.
Data are available from the few cores taken below 4000 m. The investigations were carried out on the longest core sample of each cored interval (16 specimens).

本研究于水槽中开展超声波在岩心样品内的传播特性实验，以保障换能器（transducer）、岩石试样与接收器之间具备良好的信号传输效果，同时规避耗时费力的机械样品制备流程。本研究采用定制研发的实验装置，可实现垂直于岩心轴的平面内径向纵波（P-wave）速度的测量；若岩心样品长度足够，还可通过共中心点（common mid-point, CMP）折射实验，以水作为上层介质、岩心作为下层介质，测得轴向纵波与横波（S-wave）速度。通过旋转岩心，可完成所有可变方位角下的测量工作。该系统的核心特性包括：全机械与电子操作的计算机控制、10位数字化数据采集（data acquisition）、信号叠加处理以及交互式地震记录（seismogram）分析与评估。

本次实验所用数据取自4000米以深的少量岩心样品，且针对每个取芯层位，仅选取其中最长的岩心样品开展测试（共计16个试样）。