Both automated and manual techniques were used to map
the three Westdahl lava flows of interest (1991–1992, 1964,
and pre-1964). The processing was done using the ERDAS
Imagine software. First, the region-growing technique (Haralick
& Shapiro, 1985) was applied to discriminate the
extent of the flows on the Landsat imagery. The regiongrowing
algorithm is an image segmentation technique. It
starts with a seed pixel, examines adjacent pixels, determines
the most similar one, and includes it in the region if it