Analysis of lava flow paths using remote sensing and geomorphological techniques: the case of volcanic eruptions in Afar region of Ethiopia

The lava from volcanic eruptions rapidly moves on the Earth’s surface and affects both natural and man-made features. We aim to develop a workflow using remote sensing and geomorphologic techniques to numerically determine the optimal ground sample distance (GSD) of a digital elevation model (DEM) for delineating lava flow paths. For the experiment, satellite images and a DEM of the Afar region of Ethiopia were used. The satellite images of the affected areas were segmented using large-scale mean shift image segmentation to identify the lava objects. The main centerline of the lava object from the 2008 Advanced Spaceborne Thermal Emission and Reflection Radiometer image and the flow paths from the 2000 SRTM DEM were used to determine the optimal GSD for the 2008 volcanic eruption in the Afar region. The results indicated an optimal resolution of 35 m, with a root mean square error of minimum distances of 146.89 m. This result was further compared using the 2017 case, and 35 m GSD was a satisfactory GSD for one of the major lava polygons. The results also show that the application of free and open-source geospatial technologies will be beneficial to lava flow studies by organizations with limited funding.