Gas and ash fall stunted grass growth and led to catastrophic starvation of livestock. Hekla, one of the most active volcanoes in the world, is located in the eastern tectonic zone of Iceland. This volcano has erupted on average twice per century since it became active 1104. Young lava flows are visible in the foreground. Massive fissure eruptions took place in the 10th century.
Conical volcanoes are relatively rare in Iceland.
They form when eruptions take place beneath a cover of glacier ice. Laki lava flows, southeastern Iceland. The rough lava flows are now covered by soft moss, but the terrain remains largely impassable today. Tertiary basalt forms the thick ledge over which the water falls at Fagifoss in southeastern Iceland. Utvikling av dyphav og kontinentalmarginer.