Abstract
We invented a new method and equipment necessary for extensive sequence-oriented sampling of unconsolidated Quaternary sediments. This method is which enables us to collect deeper and wider soil sections, is an application of the basic idea of Geo-slicer by Nakata and Shimazaki (1997).
The basic structure of the equipment is simple and is composed of two parts, a sampling box generally made of a long iron sheet pile with flat U-shaped cross section and a shutter of iron plate which covers the open side of the sampling box. In the operation of sampling, a sampling box is driven vertically into ground at first, and a shutter being combined with the box containing samples, and then the both box and shutter are pulled out together from the ground. A vibro-hammer or a hydraulic-hammer common in construction sites is generally used to drive them into ground.
This method was tested at two sites. On the Kamishiro fault, an active fault trace in Hakuba-mura, Nagano Prefecture, on the Itoigawa-Shizuoka Tectonic Line, we successfully extracted two 11m long soil logs 0.35m wide and 12 cm thick. From the 5m deep river bed of the Kyu-Edo in the Tokyo metropolitan area, ten 0.3 m wide, 12 cm thick and 9m deep soil logs were obtained to form an extensive soil section.
Although this sampling method is still to be improved for perfect performance, we realize that this is the most practical sampling method to obtain extensive vertical soil sections of the unconsolidated Quaternary sediments. This method may be most effectively applied in active fault studies, tsunami deposits, tephrochronology, preliminary archeological works as well as many fields of environmental studies.
