Final answer:
Direct evidence to support the claim that Eyjafjallajokull is one of the smallest volcanoes in Iceland is not commonly available; the volcano is famous for its 2010 eruption. Its size compared to other Icelandic volcanoes would normally be determined by geological surveys and satellite imagery.
Step-by-step explanation:
When discussing Eyjafjallajokull volcano and its size relative to other volcanoes in Iceland, we consider several factors to determine its ranking in size. Unfortunately, there isn't widely available direct evidence that states Eyjafjallajokull is one of the smallest volcanoes in Iceland. Eyjafjallajokull is more famous for its 2010 eruption, which disrupted air travel across Europe, rather than its size. Volcanoes in Iceland vary in size, and comparisons are often made based on the volume of the magma chamber, the height of the volcano, and the area covered by the volcanic edifice and associated lava flows. Typically, data regarding the size and volume of the volcanic structures are collected through geological surveys and satellite imagery.