Weathering and alteration products of volcanic sediments related to landslides by 2016 Kumamoto Earthquake

Abstract

2016 Kumamoto earthquake caused numerous landslides in Aso area even on relatively gradual slopes. Flat surface of landslide bottom lays in altered volcanic ash strata. XRD analysis revealed that the main component of the altered volcanic ash is halloysite (10Å). Strong earthquake may fluidize swellable clay minerals in gradual slopes.