Distinction of Chemical Composition in Groundwater by Difference Type of Landslides

Abstract

Many landslides have been carried out in surround area where are located on the north-western of Sasebo city. These are called Hokusho-type and are distributed in similar geological constitutents. But chemical compositions of groundwaters in these landslide areas differ distinctly among those. In present report, the chemical compositions of groundwaters of two landslides areas were investigated. The differences are estimated to depend on movement and materials of landslides. One of type of both landslides is collapse type and another is cohesive type. Colluvial deposits of former landslide area is active chemically weathered and alkalinity of the groundwater is high. The chemical compositions are Ca (HCO₃) ₂ and MgSO₄.
Colluvial deposits of latter landslide area has already weathered. The concentrations of chemical components are low and are the same to those of rain or stream water.
The relationship between the chemical composition of groundwater and the type of landslide was cleared by this study.