4D monitoring of active sinkholes with a Terrestrial Laser Scanner (TLS): a case study in the evaporite karst of the Ebro Valley, NE Spain - Benito-Calvo, Alfonso; Gutiérrez, Francisco Javier; Martínez-Fernández, Adrián; Carbonel, Domingo; Karampaglidis, Theodoros; Desir, Gloria; Sevil, Jorge; Guerrero, Jesús; Fabregat González, Iván; García-Arnay, Ángel (2018)