Determination of glacier retreat at Nevado del Ruiz, Santa Isabel and Tolima volcanoes, Colombia through optical image and Din-SAR

We performed a quantification of glacier retreat of Nevado del Ruiz Volcano (VNR), Nevado de Santa Isabel Volcano (VNSI) and Nevado del Tolima Volcano (VNT), using satellite images Landsat 8 OLI TIRS and coherence images obtained by DinSAR technique of Radarsat II images. Spectral indexes and supervised image classification were calculated to differentiate the ice boundary. Between 2010 and 2015 the ice sheet of the volcanoes under study has reated 24%, 42% and 60% respectively. The coherence images show similar results as those obtained by optical images. The use of coherence images can be used for the delimitation of ice and rock in glacial areas. The ash on the ice sheet is a particular phenomenon on the VNR ice cap, which complicates the delimitation of the glacier surface for that volcano.