2. Mapping lava flows using both SAR and optical
images
Based on an oblique aerial photograph, the 1991–1992
lava flow was estimated to be about 7 km long, up to 3 km
wide, and 5–10 m thick, with an area of about 5 km2 (T.
Neal, personal communication, 2002). These estimates have
since been refined using SAR imagery. Over gently sloping
terrain, the SAR backscattering signal is primarily controlled