More than 12, 900 square feet (1, 200 square meters) of Etna’s surface is covered with solid lava, and new eruptions change the volcano's height.

This slatted structure gives way to a solid timber volume as the stairs ascend beyond the height of the bookcase.

Several parameters, such as frost height, solid holdup, quantity of ice crystal and distribution of ice crystal at different level and so on can be gotten by analyzing this binary image.