CT scan data and drained direct-shear laboratory experiments on marine tephra Y-7 at site GeoB14403, Gela Basin, Strait of Sicily

To gain information on the role of marine tephra Y-7 in the framework of slope stability and failure initiation, high resolution data on radiodensity and mesoporosity was extracted from a 20 cm CT scan of whole-round section GeoB14403 5P-2. Additionally, three drained direct-shear experiments were performed on samples of this section representing the sedimentary transition from overlying homogeneous background sedimentation of silty clay to the volcanoclastic layer.