Figure 10-19. These two panels illustrate inference of volcano topography and deflation maps generated from interferometric synthetic aperture radar data acquired over Mt. Etna, Sicily. Top: produced from a single pair of ERS-1 images showing topographic contours at ~100 meter spacing. Bottom: a combination of three passes reduced to give deflation of the volcano over a one year period near the end of the latest eruptive cycle. Etna deflated by ~14 cm peak over this period. (Photo: Stanford University and ESA)