Three-dimensional critical slip surface identification and slope stability assessment of 11# lava lobe of Unzen volcano, Japan

Abstract

Althoug Unzen volcano has been declared to be in a state of relative dormancy, basing on the latcst researchthe latest formed 11# lava lobe now represents a potential slope failure mass. This paper concentrates on the stability of the 11# lava lobe and its possible critical sliding mass. Based on the proposed Geographic Information Systems (GIS) three-dimensional (3D) slope stability analysis models, a 3D locating approach has been used to identify the 3D critical sliding mass and to analyse the 3D stability of 11# lava dome. At the same time, the new 3D approach has shown the effectiveness in selecting the range of the Monte Carlo random variables and in locating the critical slip surface in different parts of the lava dome. The results are very valuable for judging the stability of the lava lobe and for planing the monitoring points.