Geotechnical Features of the Volcanic Rocks Related to the Arteara Rock Avalanche in Gran Canaria (Canary Islands, Spain)

Abstract

The Arteara rock avalanche is developed in the Fataga Group which is related to the first volcanic stage in the Gran Canaria Island (8.6–13.3 Ma). The materials of the avalanche are mainly phonolitic ignimbrites and lava flows. We have investigated the geotechnical quality of the five lithotypes distinguished in the area: (a) phonolitic lava, (b) phonolitic agglomerate breccia, (c) reddish non-welded ignimbrite, (d) welded fiamme-bearing ignimbrite, and (e) pumice tuff with lithics. The weak geotechnical properties of the reddish non-welded ignimbrite, the pumice tuff with lithics and the agglomerate breccia, and their location at the middle of the slope suggest that these lithotypes can be regarded as potential sliding surfaces of the avalanche. The geomechanical features of the volcanic rocks found in this study could be very useful for future studies concerning the modelling of the mechanism of failure and run out of the Arteara rock avalanche.